third_party/protobuf/java/src/main/java/com/google/protobuf/GeneratedMessage.java

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
getParserForType
enableAlwaysUseFieldBuildersForTesting
internalGetFieldAccessorTable
getDescriptorForType
getAllFieldsMutable
isInitialized
getAllFields
hasField
getField
getRepeatedFieldCount
getRepeatedField
getUnknownFields
parseUnknownField
makeExtensionsImmutable
newBuilderForType
markDirty
SuppressWarnings
dispose
onBuilt
markClean
isClean
clone
clear
internalGetFieldAccessorTable
getDescriptorForType
getAllFields
getAllFieldsMutable
newBuilderForField
getFieldBuilder
hasField
getField
setField
clearField
getRepeatedFieldCount
getRepeatedField
setRepeatedField
addRepeatedField
setUnknownFields
mergeUnknownFields
isInitialized
getUnknownFields
parseUnknownField
markDirty
getParentForChildren
onChanged
hasExtension
getExtensionCount
getExtension
getExtension
verifyExtensionContainingType
hasExtension
getExtensionCount
SuppressWarnings
getExtension
SuppressWarnings
getExtension
extensionsAreInitialized
isInitialized
parseUnknownField
makeExtensionsImmutable
writeUntil
newExtensionWriter
newMessageSetExtensionWriter
extensionsSerializedSize
extensionsSerializedSizeAsMessageSet
getExtensionFields
getAllFields
hasField
getField
getRepeatedFieldCount
getRepeatedField
verifyContainingType
SuppressWarnings
clear
clone
ensureExtensionsIsMutable
verifyExtensionContainingType
hasExtension
getExtensionCount
getExtension
getExtension
setExtension
setExtension
addExtension
clearExtension
extensionsAreInitialized
buildExtensions
isInitialized
parseUnknownField
getAllFields
getField
getRepeatedFieldCount
getRepeatedField
hasField
setField
clearField
setRepeatedField
addRepeatedField
mergeExtensionFields
verifyContainingType
getDescriptor
newMessageScopedGeneratedExtension
newFileScopedGeneratedExtension
internalInit
getDescriptor
getMessageDefaultInstance
SuppressWarnings
fromReflectionType
singularFromReflectionType
SuppressWarnings
toReflectionType
singularToReflectionType
SuppressWarnings
getMethodOrDie
invokeOrDie
ensureFieldAccessorsInitialized
getField
get
get
set
getRepeated
getRepeated
setRepeated
addRepeated
has
has
getRepeatedCount
getRepeatedCount
clear
newBuilder
getBuilder
get
get
set
getRepeated
getRepeated
setRepeated
addRepeated
has
has
getRepeatedCount
getRepeatedCount
clear
newBuilder
getBuilder
get
get
set
getRepeated
getRepeated
setRepeated
addRepeated
has
has
getRepeatedCount
getRepeatedCount
clear
newBuilder
getBuilder
get
get
set
SuppressWarnings
get
SuppressWarnings
get
getRepeated
getRepeated
setRepeated
addRepeated
coerceType
set
newBuilder
getBuilder
coerceType
setRepeated
addRepeated
newBuilder
writeReplace
// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// http://code.google.com/p/protobuf/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package com.google.protobuf;

import com.google.protobuf.Descriptors.Descriptor;
import com.google.protobuf.Descriptors.EnumValueDescriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;

import java.io.IOException;
import java.io.ObjectStreamException;
import java.io.Serializable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

/**
 * All generated protocol message classes extend this class.  This class
 * implements most of the Message and Builder interfaces using Java reflection.
 * Users can ignore this class and pretend that generated messages implement
 * the Message interface directly.
 *
 * @author kenton@google.com Kenton Varda
 */
public abstract class GeneratedMessage extends AbstractMessage
    implements Serializable {
  private static final long serialVersionUID = 1L;

  /**
   * For testing. Allows a test to disable the optimization that avoids using
   * field builders for nested messages until they are requested. By disabling
   * this optimization, existing tests can be reused to test the field builders.
   */
  protected static boolean alwaysUseFieldBuilders = false;

  protected GeneratedMessage() {
  }

  protected GeneratedMessage(Builder<?> builder) {
  }

  public Parser<? extends Message> getParserForType() {
    throw new UnsupportedOperationException(
        "This is supposed to be overridden by subclasses.");
  }

 /**
  * For testing. Allows a test to disable the optimization that avoids using
  * field builders for nested messages until they are requested. By disabling
  * this optimization, existing tests can be reused to test the field builders.
  * See {@link RepeatedFieldBuilder} and {@link SingleFieldBuilder}.
  */
  static void enableAlwaysUseFieldBuildersForTesting() {
    alwaysUseFieldBuilders = true;
  }

  /**
   * Get the FieldAccessorTable for this type.  We can't have the message
   * class pass this in to the constructor because of bootstrapping trouble
   * with DescriptorProtos.
   */
  protected abstract FieldAccessorTable internalGetFieldAccessorTable();

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public Descriptor getDescriptorForType() {
    return internalGetFieldAccessorTable().descriptor;
  }

  /** Internal helper which returns a mutable map. */
  private Map<FieldDescriptor, Object> getAllFieldsMutable() {
    final TreeMap<FieldDescriptor, Object> result =
      new TreeMap<FieldDescriptor, Object>();
    final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
    for (final FieldDescriptor field : descriptor.getFields()) {
      if (field.isRepeated()) {
        final List<?> value = (List<?>) getField(field);
        if (!value.isEmpty()) {
          result.put(field, value);
        }
      } else {
        if (hasField(field)) {
          result.put(field, getField(field));
        }
      }
    }
    return result;
  }

  @Override
  public boolean isInitialized() {
    for (final FieldDescriptor field : getDescriptorForType().getFields()) {
      // Check that all required fields are present.
      if (field.isRequired()) {
        if (!hasField(field)) {
          return false;
        }
      }
      // Check that embedded messages are initialized.
      if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
        if (field.isRepeated()) {
          @SuppressWarnings("unchecked") final
          List<Message> messageList = (List<Message>) getField(field);
          for (final Message element : messageList) {
            if (!element.isInitialized()) {
              return false;
            }
          }
        } else {
          if (hasField(field) && !((Message) getField(field)).isInitialized()) {
            return false;
          }
        }
      }
    }

    return true;
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public Map<FieldDescriptor, Object> getAllFields() {
    return Collections.unmodifiableMap(getAllFieldsMutable());
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public boolean hasField(final FieldDescriptor field) {
    return internalGetFieldAccessorTable().getField(field).has(this);
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public Object getField(final FieldDescriptor field) {
    return internalGetFieldAccessorTable().getField(field).get(this);
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public int getRepeatedFieldCount(final FieldDescriptor field) {
    return internalGetFieldAccessorTable().getField(field)
      .getRepeatedCount(this);
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public Object getRepeatedField(final FieldDescriptor field, final int index) {
    return internalGetFieldAccessorTable().getField(field)
      .getRepeated(this, index);
  }

  //@Override (Java 1.6 override semantics, but we must support 1.5)
  public UnknownFieldSet getUnknownFields() {
    throw new UnsupportedOperationException(
        "This is supposed to be overridden by subclasses.");
  }

  /**
   * Called by subclasses to parse an unknown field.
   * @return {@code true} unless the tag is an end-group tag.
   */
  protected boolean parseUnknownField(
      CodedInputStream input,
      UnknownFieldSet.Builder unknownFields,
      ExtensionRegistryLite extensionRegistry,
      int tag) throws IOException {
    return unknownFields.mergeFieldFrom(tag, input);
  }

  /**
   * Used by parsing constructors in generated classes.
   */
  protected void makeExtensionsImmutable() {
    // Noop for messages without extensions.
  }

  protected abstract Message.Builder newBuilderForType(BuilderParent parent);

  /**
   * Interface for the parent of a Builder that allows the builder to
   * communicate invalidations back to the parent for use when using nested
   * builders.
   */
  protected interface BuilderParent {

    /**
     * A builder becomes dirty whenever a field is modified -- including fields
     * in nested builders -- and becomes clean when build() is called.  Thus,
     * when a builder becomes dirty, all its parents become dirty as well, and
     * when it becomes clean, all its children become clean.  The dirtiness
     * state is used to invalidate certain cached values.
     * <br>
     * To this end, a builder calls markAsDirty() on its parent whenever it
     * transitions from clean to dirty.  The parent must propagate this call to
     * its own parent, unless it was already dirty, in which case the
     * grandparent must necessarily already be dirty as well.  The parent can
     * only transition back to "clean" after calling build() on all children.
     */
    void markDirty();
  }

  @SuppressWarnings("unchecked")
  public abstract static class Builder <BuilderType extends Builder>
      extends AbstractMessage.Builder<BuilderType> {

    private BuilderParent builderParent;

    private BuilderParentImpl meAsParent;

    // Indicates that we've built a message and so we are now obligated
    // to dispatch dirty invalidations. See GeneratedMessage.BuilderListener.
    private boolean isClean;

    private UnknownFieldSet unknownFields =
        UnknownFieldSet.getDefaultInstance();

    protected Builder() {
      this(null);
    }

    protected Builder(BuilderParent builderParent) {
      this.builderParent = builderParent;
    }

    void dispose() {
      builderParent = null;
    }

    /**
     * Called by the subclass when a message is built.
     */
    protected void onBuilt() {
      if (builderParent != null) {
        markClean();
      }
    }

    /**
     * Called by the subclass or a builder to notify us that a message was
     * built and may be cached and therefore invalidations are needed.
     */
    protected void markClean() {
      this.isClean = true;
    }

    /**
     * Gets whether invalidations are needed
     *
     * @return whether invalidations are needed
     */
    protected boolean isClean() {
      return isClean;
    }

    // This is implemented here only to work around an apparent bug in the
    // Java compiler and/or build system.  See bug #1898463.  The mere presence
    // of this dummy clone() implementation makes it go away.
    @Override
    public BuilderType clone() {
      throw new UnsupportedOperationException(
          "This is supposed to be overridden by subclasses.");
    }

    /**
     * Called by the initialization and clear code paths to allow subclasses to
     * reset any of their builtin fields back to the initial values.
     */
    public BuilderType clear() {
      unknownFields = UnknownFieldSet.getDefaultInstance();
      onChanged();
      return (BuilderType) this;
    }

    /**
     * Get the FieldAccessorTable for this type.  We can't have the message
     * class pass this in to the constructor because of bootstrapping trouble
     * with DescriptorProtos.
     */
    protected abstract FieldAccessorTable internalGetFieldAccessorTable();

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public Descriptor getDescriptorForType() {
      return internalGetFieldAccessorTable().descriptor;
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public Map<FieldDescriptor, Object> getAllFields() {
      return Collections.unmodifiableMap(getAllFieldsMutable());
    }

    /** Internal helper which returns a mutable map. */
    private Map<FieldDescriptor, Object> getAllFieldsMutable() {
      final TreeMap<FieldDescriptor, Object> result =
        new TreeMap<FieldDescriptor, Object>();
      final Descriptor descriptor = internalGetFieldAccessorTable().descriptor;
      for (final FieldDescriptor field : descriptor.getFields()) {
        if (field.isRepeated()) {
          final List value = (List) getField(field);
          if (!value.isEmpty()) {
            result.put(field, value);
          }
        } else {
          if (hasField(field)) {
            result.put(field, getField(field));
          }
        }
      }
      return result;
    }

    public Message.Builder newBuilderForField(
        final FieldDescriptor field) {
      return internalGetFieldAccessorTable().getField(field).newBuilder();
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
      return internalGetFieldAccessorTable().getField(field).getBuilder(this);
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public boolean hasField(final FieldDescriptor field) {
      return internalGetFieldAccessorTable().getField(field).has(this);
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public Object getField(final FieldDescriptor field) {
      Object object = internalGetFieldAccessorTable().getField(field).get(this);
      if (field.isRepeated()) {
        // The underlying list object is still modifiable at this point.
        // Make sure not to expose the modifiable list to the caller.
        return Collections.unmodifiableList((List) object);
      } else {
        return object;
      }
    }

    public BuilderType setField(final FieldDescriptor field,
                                final Object value) {
      internalGetFieldAccessorTable().getField(field).set(this, value);
      return (BuilderType) this;
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public BuilderType clearField(final FieldDescriptor field) {
      internalGetFieldAccessorTable().getField(field).clear(this);
      return (BuilderType) this;
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public int getRepeatedFieldCount(final FieldDescriptor field) {
      return internalGetFieldAccessorTable().getField(field)
          .getRepeatedCount(this);
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public Object getRepeatedField(final FieldDescriptor field,
                                   final int index) {
      return internalGetFieldAccessorTable().getField(field)
          .getRepeated(this, index);
    }

    public BuilderType setRepeatedField(final FieldDescriptor field,
                                        final int index, final Object value) {
      internalGetFieldAccessorTable().getField(field)
        .setRepeated(this, index, value);
      return (BuilderType) this;
    }

    public BuilderType addRepeatedField(final FieldDescriptor field,
                                        final Object value) {
      internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
      return (BuilderType) this;
    }

    public final BuilderType setUnknownFields(
        final UnknownFieldSet unknownFields) {
      this.unknownFields = unknownFields;
      onChanged();
      return (BuilderType) this;
    }

    @Override
    public final BuilderType mergeUnknownFields(
        final UnknownFieldSet unknownFields) {
      this.unknownFields =
        UnknownFieldSet.newBuilder(this.unknownFields)
                       .mergeFrom(unknownFields)
                       .build();
      onChanged();
      return (BuilderType) this;
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public boolean isInitialized() {
      for (final FieldDescriptor field : getDescriptorForType().getFields()) {
        // Check that all required fields are present.
        if (field.isRequired()) {
          if (!hasField(field)) {
            return false;
          }
        }
        // Check that embedded messages are initialized.
        if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
          if (field.isRepeated()) {
            @SuppressWarnings("unchecked") final
            List<Message> messageList = (List<Message>) getField(field);
            for (final Message element : messageList) {
              if (!element.isInitialized()) {
                return false;
              }
            }
          } else {
            if (hasField(field) &&
                !((Message) getField(field)).isInitialized()) {
              return false;
            }
          }
        }
      }
      return true;
    }

    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final UnknownFieldSet getUnknownFields() {
      return unknownFields;
    }

    /**
     * Called by subclasses to parse an unknown field.
     * @return {@code true} unless the tag is an end-group tag.
     */
    protected boolean parseUnknownField(
        final CodedInputStream input,
        final UnknownFieldSet.Builder unknownFields,
        final ExtensionRegistryLite extensionRegistry,
        final int tag) throws IOException {
      return unknownFields.mergeFieldFrom(tag, input);
    }

    /**
     * Implementation of {@link BuilderParent} for giving to our children. This
     * small inner class makes it so we don't publicly expose the BuilderParent
     * methods.
     */
    private class BuilderParentImpl implements BuilderParent {

      //@Override (Java 1.6 override semantics, but we must support 1.5)
      public void markDirty() {
        onChanged();
      }
    }

    /**
     * Gets the {@link BuilderParent} for giving to our children.
     * @return The builder parent for our children.
     */
    protected BuilderParent getParentForChildren() {
      if (meAsParent == null) {
        meAsParent = new BuilderParentImpl();
      }
      return meAsParent;
    }

    /**
     * Called when a the builder or one of its nested children has changed
     * and any parent should be notified of its invalidation.
     */
    protected final void onChanged() {
      if (isClean && builderParent != null) {
        builderParent.markDirty();

        // Don't keep dispatching invalidations until build is called again.
        isClean = false;
      }
    }
  }

  // =================================================================
  // Extensions-related stuff

  public interface ExtendableMessageOrBuilder<
      MessageType extends ExtendableMessage> extends MessageOrBuilder {

    /** Check if a singular extension is present. */
    <Type> boolean hasExtension(
        GeneratedExtension<MessageType, Type> extension);

    /** Get the number of elements in a repeated extension. */
    <Type> int getExtensionCount(
        GeneratedExtension<MessageType, List<Type>> extension);

    /** Get the value of an extension. */
    <Type> Type getExtension(GeneratedExtension<MessageType, Type> extension);

    /** Get one element of a repeated extension. */
    <Type> Type getExtension(
        GeneratedExtension<MessageType, List<Type>> extension,
        int index);
  }

  /**
   * Generated message classes for message types that contain extension ranges
   * subclass this.
   *
   * <p>This class implements type-safe accessors for extensions.  They
   * implement all the same operations that you can do with normal fields --
   * e.g. "has", "get", and "getCount" -- but for extensions.  The extensions
   * are identified using instances of the class {@link GeneratedExtension};
   * the protocol compiler generates a static instance of this class for every
   * extension in its input.  Through the magic of generics, all is made
   * type-safe.
   *
   * <p>For example, imagine you have the {@code .proto} file:
   *
   * <pre>
   * option java_class = "MyProto";
   *
   * message Foo {
   *   extensions 1000 to max;
   * }
   *
   * extend Foo {
   *   optional int32 bar;
   * }
   * </pre>
   *
   * <p>Then you might write code like:
   *
   * <pre>
   * MyProto.Foo foo = getFoo();
   * int i = foo.getExtension(MyProto.bar);
   * </pre>
   *
   * <p>See also {@link ExtendableBuilder}.
   */
  public abstract static class ExtendableMessage<
        MessageType extends ExtendableMessage>
      extends GeneratedMessage
      implements ExtendableMessageOrBuilder<MessageType> {

    private final FieldSet<FieldDescriptor> extensions;

    protected ExtendableMessage() {
      this.extensions = FieldSet.newFieldSet();
    }

    protected ExtendableMessage(
        ExtendableBuilder<MessageType, ?> builder) {
      super(builder);
      this.extensions = builder.buildExtensions();
    }

    private void verifyExtensionContainingType(
        final GeneratedExtension<MessageType, ?> extension) {
      if (extension.getDescriptor().getContainingType() !=
          getDescriptorForType()) {
        // This can only happen if someone uses unchecked operations.
        throw new IllegalArgumentException(
          "Extension is for type \"" +
          extension.getDescriptor().getContainingType().getFullName() +
          "\" which does not match message type \"" +
          getDescriptorForType().getFullName() + "\".");
      }
    }

    /** Check if a singular extension is present. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> boolean hasExtension(
        final GeneratedExtension<MessageType, Type> extension) {
      verifyExtensionContainingType(extension);
      return extensions.hasField(extension.getDescriptor());
    }

    /** Get the number of elements in a repeated extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> int getExtensionCount(
        final GeneratedExtension<MessageType, List<Type>> extension) {
      verifyExtensionContainingType(extension);
      final FieldDescriptor descriptor = extension.getDescriptor();
      return extensions.getRepeatedFieldCount(descriptor);
    }

    /** Get the value of an extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    @SuppressWarnings("unchecked")
    public final <Type> Type getExtension(
        final GeneratedExtension<MessageType, Type> extension) {
      verifyExtensionContainingType(extension);
      FieldDescriptor descriptor = extension.getDescriptor();
      final Object value = extensions.getField(descriptor);
      if (value == null) {
        if (descriptor.isRepeated()) {
          return (Type) Collections.emptyList();
        } else if (descriptor.getJavaType() ==
                   FieldDescriptor.JavaType.MESSAGE) {
          return (Type) extension.getMessageDefaultInstance();
        } else {
          return (Type) extension.fromReflectionType(
              descriptor.getDefaultValue());
        }
      } else {
        return (Type) extension.fromReflectionType(value);
      }
    }

    /** Get one element of a repeated extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    @SuppressWarnings("unchecked")
    public final <Type> Type getExtension(
        final GeneratedExtension<MessageType, List<Type>> extension,
        final int index) {
      verifyExtensionContainingType(extension);
      FieldDescriptor descriptor = extension.getDescriptor();
      return (Type) extension.singularFromReflectionType(
          extensions.getRepeatedField(descriptor, index));
    }

    /** Called by subclasses to check if all extensions are initialized. */
    protected boolean extensionsAreInitialized() {
      return extensions.isInitialized();
    }

    @Override
    public boolean isInitialized() {
      return super.isInitialized() && extensionsAreInitialized();
    }

    @Override
    protected boolean parseUnknownField(
        CodedInputStream input,
        UnknownFieldSet.Builder unknownFields,
        ExtensionRegistryLite extensionRegistry,
        int tag) throws IOException {
      return AbstractMessage.Builder.mergeFieldFrom(
        input, unknownFields, extensionRegistry, getDescriptorForType(),
        null, extensions, tag);
    }

    /**
     * Used by parsing constructors in generated classes.
     */
    @Override
    protected void makeExtensionsImmutable() {
      extensions.makeImmutable();
    }

    /**
     * Used by subclasses to serialize extensions.  Extension ranges may be
     * interleaved with field numbers, but we must write them in canonical
     * (sorted by field number) order.  ExtensionWriter helps us write
     * individual ranges of extensions at once.
     */
    protected class ExtensionWriter {
      // Imagine how much simpler this code would be if Java iterators had
      // a way to get the next element without advancing the iterator.

      private final Iterator<Map.Entry<FieldDescriptor, Object>> iter =
        extensions.iterator();
      private Map.Entry<FieldDescriptor, Object> next;
      private final boolean messageSetWireFormat;

      private ExtensionWriter(final boolean messageSetWireFormat) {
        if (iter.hasNext()) {
          next = iter.next();
        }
        this.messageSetWireFormat = messageSetWireFormat;
      }

      public void writeUntil(final int end, final CodedOutputStream output)
                             throws IOException {
        while (next != null && next.getKey().getNumber() < end) {
          FieldDescriptor descriptor = next.getKey();
          if (messageSetWireFormat && descriptor.getLiteJavaType() ==
                  WireFormat.JavaType.MESSAGE &&
              !descriptor.isRepeated()) {
            if (next instanceof LazyField.LazyEntry<?>) {
              output.writeRawMessageSetExtension(descriptor.getNumber(),
                  ((LazyField.LazyEntry<?>) next).getField().toByteString());
            } else {
              output.writeMessageSetExtension(descriptor.getNumber(),
                                              (Message) next.getValue());
            }
          } else {
            // TODO(xiangl): Taken care of following code, it may cause
            // problem when we use LazyField for normal fields/extensions.
            // Due to the optional field can be duplicated at the end of
            // serialized bytes, which will make the serialized size change
            // after lazy field parsed. So when we use LazyField globally,
            // we need to change the following write method to write cached
            // bytes directly rather than write the parsed message.
            FieldSet.writeField(descriptor, next.getValue(), output);
          }
          if (iter.hasNext()) {
            next = iter.next();
          } else {
            next = null;
          }
        }
      }
    }

    protected ExtensionWriter newExtensionWriter() {
      return new ExtensionWriter(false);
    }
    protected ExtensionWriter newMessageSetExtensionWriter() {
      return new ExtensionWriter(true);
    }

    /** Called by subclasses to compute the size of extensions. */
    protected int extensionsSerializedSize() {
      return extensions.getSerializedSize();
    }
    protected int extensionsSerializedSizeAsMessageSet() {
      return extensions.getMessageSetSerializedSize();
    }

    // ---------------------------------------------------------------
    // Reflection

    protected Map<FieldDescriptor, Object> getExtensionFields() {
      return extensions.getAllFields();
    }

    @Override
    public Map<FieldDescriptor, Object> getAllFields() {
      final Map<FieldDescriptor, Object> result = super.getAllFieldsMutable();
      result.putAll(getExtensionFields());
      return Collections.unmodifiableMap(result);
    }

    @Override
    public boolean hasField(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.hasField(field);
      } else {
        return super.hasField(field);
      }
    }

    @Override
    public Object getField(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        final Object value = extensions.getField(field);
        if (value == null) {
          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
            // Lacking an ExtensionRegistry, we have no way to determine the
            // extension's real type, so we return a DynamicMessage.
            return DynamicMessage.getDefaultInstance(field.getMessageType());
          } else {
            return field.getDefaultValue();
          }
        } else {
          return value;
        }
      } else {
        return super.getField(field);
      }
    }

    @Override
    public int getRepeatedFieldCount(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.getRepeatedFieldCount(field);
      } else {
        return super.getRepeatedFieldCount(field);
      }
    }

    @Override
    public Object getRepeatedField(final FieldDescriptor field,
                                   final int index) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.getRepeatedField(field, index);
      } else {
        return super.getRepeatedField(field, index);
      }
    }

    private void verifyContainingType(final FieldDescriptor field) {
      if (field.getContainingType() != getDescriptorForType()) {
        throw new IllegalArgumentException(
          "FieldDescriptor does not match message type.");
      }
    }
  }

  /**
   * Generated message builders for message types that contain extension ranges
   * subclass this.
   *
   * <p>This class implements type-safe accessors for extensions.  They
   * implement all the same operations that you can do with normal fields --
   * e.g. "get", "set", and "add" -- but for extensions.  The extensions are
   * identified using instances of the class {@link GeneratedExtension}; the
   * protocol compiler generates a static instance of this class for every
   * extension in its input.  Through the magic of generics, all is made
   * type-safe.
   *
   * <p>For example, imagine you have the {@code .proto} file:
   *
   * <pre>
   * option java_class = "MyProto";
   *
   * message Foo {
   *   extensions 1000 to max;
   * }
   *
   * extend Foo {
   *   optional int32 bar;
   * }
   * </pre>
   *
   * <p>Then you might write code like:
   *
   * <pre>
   * MyProto.Foo foo =
   *   MyProto.Foo.newBuilder()
   *     .setExtension(MyProto.bar, 123)
   *     .build();
   * </pre>
   *
   * <p>See also {@link ExtendableMessage}.
   */
  @SuppressWarnings("unchecked")
  public abstract static class ExtendableBuilder<
        MessageType extends ExtendableMessage,
        BuilderType extends ExtendableBuilder>
      extends Builder<BuilderType>
      implements ExtendableMessageOrBuilder<MessageType> {

    private FieldSet<FieldDescriptor> extensions = FieldSet.emptySet();

    protected ExtendableBuilder() {}

    protected ExtendableBuilder(
        BuilderParent parent) {
      super(parent);
    }

    @Override
    public BuilderType clear() {
      extensions = FieldSet.emptySet();
      return super.clear();
    }

    // This is implemented here only to work around an apparent bug in the
    // Java compiler and/or build system.  See bug #1898463.  The mere presence
    // of this dummy clone() implementation makes it go away.
    @Override
    public BuilderType clone() {
      throw new UnsupportedOperationException(
          "This is supposed to be overridden by subclasses.");
    }

    private void ensureExtensionsIsMutable() {
      if (extensions.isImmutable()) {
        extensions = extensions.clone();
      }
    }

    private void verifyExtensionContainingType(
        final GeneratedExtension<MessageType, ?> extension) {
      if (extension.getDescriptor().getContainingType() !=
          getDescriptorForType()) {
        // This can only happen if someone uses unchecked operations.
        throw new IllegalArgumentException(
          "Extension is for type \"" +
          extension.getDescriptor().getContainingType().getFullName() +
          "\" which does not match message type \"" +
          getDescriptorForType().getFullName() + "\".");
      }
    }

    /** Check if a singular extension is present. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> boolean hasExtension(
        final GeneratedExtension<MessageType, Type> extension) {
      verifyExtensionContainingType(extension);
      return extensions.hasField(extension.getDescriptor());
    }

    /** Get the number of elements in a repeated extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> int getExtensionCount(
        final GeneratedExtension<MessageType, List<Type>> extension) {
      verifyExtensionContainingType(extension);
      final FieldDescriptor descriptor = extension.getDescriptor();
      return extensions.getRepeatedFieldCount(descriptor);
    }

    /** Get the value of an extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> Type getExtension(
        final GeneratedExtension<MessageType, Type> extension) {
      verifyExtensionContainingType(extension);
      FieldDescriptor descriptor = extension.getDescriptor();
      final Object value = extensions.getField(descriptor);
      if (value == null) {
        if (descriptor.isRepeated()) {
          return (Type) Collections.emptyList();
        } else if (descriptor.getJavaType() ==
                   FieldDescriptor.JavaType.MESSAGE) {
          return (Type) extension.getMessageDefaultInstance();
        } else {
          return (Type) extension.fromReflectionType(
              descriptor.getDefaultValue());
        }
      } else {
        return (Type) extension.fromReflectionType(value);
      }
    }

    /** Get one element of a repeated extension. */
    //@Override (Java 1.6 override semantics, but we must support 1.5)
    public final <Type> Type getExtension(
        final GeneratedExtension<MessageType, List<Type>> extension,
        final int index) {
      verifyExtensionContainingType(extension);
      FieldDescriptor descriptor = extension.getDescriptor();
      return (Type) extension.singularFromReflectionType(
          extensions.getRepeatedField(descriptor, index));
    }

    /** Set the value of an extension. */
    public final <Type> BuilderType setExtension(
        final GeneratedExtension<MessageType, Type> extension,
        final Type value) {
      verifyExtensionContainingType(extension);
      ensureExtensionsIsMutable();
      final FieldDescriptor descriptor = extension.getDescriptor();
      extensions.setField(descriptor, extension.toReflectionType(value));
      onChanged();
      return (BuilderType) this;
    }

    /** Set the value of one element of a repeated extension. */
    public final <Type> BuilderType setExtension(
        final GeneratedExtension<MessageType, List<Type>> extension,
        final int index, final Type value) {
      verifyExtensionContainingType(extension);
      ensureExtensionsIsMutable();
      final FieldDescriptor descriptor = extension.getDescriptor();
      extensions.setRepeatedField(
        descriptor, index,
        extension.singularToReflectionType(value));
      onChanged();
      return (BuilderType) this;
    }

    /** Append a value to a repeated extension. */
    public final <Type> BuilderType addExtension(
        final GeneratedExtension<MessageType, List<Type>> extension,
        final Type value) {
      verifyExtensionContainingType(extension);
      ensureExtensionsIsMutable();
      final FieldDescriptor descriptor = extension.getDescriptor();
      extensions.addRepeatedField(
          descriptor, extension.singularToReflectionType(value));
      onChanged();
      return (BuilderType) this;
    }

    /** Clear an extension. */
    public final <Type> BuilderType clearExtension(
        final GeneratedExtension<MessageType, ?> extension) {
      verifyExtensionContainingType(extension);
      ensureExtensionsIsMutable();
      extensions.clearField(extension.getDescriptor());
      onChanged();
      return (BuilderType) this;
    }

    /** Called by subclasses to check if all extensions are initialized. */
    protected boolean extensionsAreInitialized() {
      return extensions.isInitialized();
    }

    /**
     * Called by the build code path to create a copy of the extensions for
     * building the message.
     */
    private FieldSet<FieldDescriptor> buildExtensions() {
      extensions.makeImmutable();
      return extensions;
    }

    @Override
    public boolean isInitialized() {
      return super.isInitialized() && extensionsAreInitialized();
    }

    /**
     * Called by subclasses to parse an unknown field or an extension.
     * @return {@code true} unless the tag is an end-group tag.
     */
    @Override
    protected boolean parseUnknownField(
        final CodedInputStream input,
        final UnknownFieldSet.Builder unknownFields,
        final ExtensionRegistryLite extensionRegistry,
        final int tag) throws IOException {
      return AbstractMessage.Builder.mergeFieldFrom(
        input, unknownFields, extensionRegistry, getDescriptorForType(),
        this, null, tag);
    }

    // ---------------------------------------------------------------
    // Reflection

    @Override
    public Map<FieldDescriptor, Object> getAllFields() {
      final Map<FieldDescriptor, Object> result = super.getAllFieldsMutable();
      result.putAll(extensions.getAllFields());
      return Collections.unmodifiableMap(result);
    }

    @Override
    public Object getField(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        final Object value = extensions.getField(field);
        if (value == null) {
          if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
            // Lacking an ExtensionRegistry, we have no way to determine the
            // extension's real type, so we return a DynamicMessage.
            return DynamicMessage.getDefaultInstance(field.getMessageType());
          } else {
            return field.getDefaultValue();
          }
        } else {
          return value;
        }
      } else {
        return super.getField(field);
      }
    }

    @Override
    public int getRepeatedFieldCount(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.getRepeatedFieldCount(field);
      } else {
        return super.getRepeatedFieldCount(field);
      }
    }

    @Override
    public Object getRepeatedField(final FieldDescriptor field,
                                   final int index) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.getRepeatedField(field, index);
      } else {
        return super.getRepeatedField(field, index);
      }
    }

    @Override
    public boolean hasField(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        return extensions.hasField(field);
      } else {
        return super.hasField(field);
      }
    }

    @Override
    public BuilderType setField(final FieldDescriptor field,
                                final Object value) {
      if (field.isExtension()) {
        verifyContainingType(field);
        ensureExtensionsIsMutable();
        extensions.setField(field, value);
        onChanged();
        return (BuilderType) this;
      } else {
        return super.setField(field, value);
      }
    }

    @Override
    public BuilderType clearField(final FieldDescriptor field) {
      if (field.isExtension()) {
        verifyContainingType(field);
        ensureExtensionsIsMutable();
        extensions.clearField(field);
        onChanged();
        return (BuilderType) this;
      } else {
        return super.clearField(field);
      }
    }

    @Override
    public BuilderType setRepeatedField(final FieldDescriptor field,
                                        final int index, final Object value) {
      if (field.isExtension()) {
        verifyContainingType(field);
        ensureExtensionsIsMutable();
        extensions.setRepeatedField(field, index, value);
        onChanged();
        return (BuilderType) this;
      } else {
        return super.setRepeatedField(field, index, value);
      }
    }

    @Override
    public BuilderType addRepeatedField(final FieldDescriptor field,
                                        final Object value) {
      if (field.isExtension()) {
        verifyContainingType(field);
        ensureExtensionsIsMutable();
        extensions.addRepeatedField(field, value);
        onChanged();
        return (BuilderType) this;
      } else {
        return super.addRepeatedField(field, value);
      }
    }

    protected final void mergeExtensionFields(final ExtendableMessage other) {
      ensureExtensionsIsMutable();
      extensions.mergeFrom(other.extensions);
      onChanged();
    }

    private void verifyContainingType(final FieldDescriptor field) {
      if (field.getContainingType() != getDescriptorForType()) {
        throw new IllegalArgumentException(
          "FieldDescriptor does not match message type.");
      }
    }
  }

  // -----------------------------------------------------------------

  /**
   * Gets the descriptor for an extension. The implementation depends on whether
   * the extension is scoped in the top level of a file or scoped in a Message.
   */
  private static interface ExtensionDescriptorRetriever {
    FieldDescriptor getDescriptor();
  }

  /** For use by generated code only. */
  public static <ContainingType extends Message, Type>
      GeneratedExtension<ContainingType, Type>
      newMessageScopedGeneratedExtension(final Message scope,
                                         final int descriptorIndex,
                                         final Class singularType,
                                         final Message defaultInstance) {
    // For extensions scoped within a Message, we use the Message to resolve
    // the outer class's descriptor, from which the extension descriptor is
    // obtained.
    return new GeneratedExtension<ContainingType, Type>(
        new ExtensionDescriptorRetriever() {
          //@Override (Java 1.6 override semantics, but we must support 1.5)
          public FieldDescriptor getDescriptor() {
            return scope.getDescriptorForType().getExtensions()
                .get(descriptorIndex);
          }
        },
        singularType,
        defaultInstance);
  }

  /** For use by generated code only. */
  public static <ContainingType extends Message, Type>
     GeneratedExtension<ContainingType, Type>
     newFileScopedGeneratedExtension(final Class singularType,
                                     final Message defaultInstance) {
    // For extensions scoped within a file, we rely on the outer class's
    // static initializer to call internalInit() on the extension when the
    // descriptor is available.
    return new GeneratedExtension<ContainingType, Type>(
        null,  // ExtensionDescriptorRetriever is initialized in internalInit();
        singularType,
        defaultInstance);
  }

  /**
   * Type used to represent generated extensions.  The protocol compiler
   * generates a static singleton instance of this class for each extension.
   *
   * <p>For example, imagine you have the {@code .proto} file:
   *
   * <pre>
   * option java_class = "MyProto";
   *
   * message Foo {
   *   extensions 1000 to max;
   * }
   *
   * extend Foo {
   *   optional int32 bar;
   * }
   * </pre>
   *
   * <p>Then, {@code MyProto.Foo.bar} has type
   * {@code GeneratedExtension<MyProto.Foo, Integer>}.
   *
   * <p>In general, users should ignore the details of this type, and simply use
   * these static singletons as parameters to the extension accessors defined
   * in {@link ExtendableMessage} and {@link ExtendableBuilder}.
   */
  public static final class GeneratedExtension<
      ContainingType extends Message, Type> {
    // TODO(kenton):  Find ways to avoid using Java reflection within this
    //   class.  Also try to avoid suppressing unchecked warnings.

    // We can't always initialize the descriptor of a GeneratedExtension when
    // we first construct it due to initialization order difficulties (namely,
    // the descriptor may not have been constructed yet, since it is often
    // constructed by the initializer of a separate module).
    //
    // In the case of nested extensions, we initialize the
    // ExtensionDescriptorRetriever with an instance that uses the scoping
    // Message's default instance to retrieve the extension's descriptor.
    //
    // In the case of non-nested extensions, we initialize the
    // ExtensionDescriptorRetriever to null and rely on the outer class's static
    // initializer to call internalInit() after the descriptor has been parsed.
    private GeneratedExtension(ExtensionDescriptorRetriever descriptorRetriever,
                               Class singularType,
                               Message messageDefaultInstance) {
      if (Message.class.isAssignableFrom(singularType) &&
          !singularType.isInstance(messageDefaultInstance)) {
        throw new IllegalArgumentException(
            "Bad messageDefaultInstance for " + singularType.getName());
      }
      this.descriptorRetriever = descriptorRetriever;
      this.singularType = singularType;
      this.messageDefaultInstance = messageDefaultInstance;

      if (ProtocolMessageEnum.class.isAssignableFrom(singularType)) {
        this.enumValueOf = getMethodOrDie(singularType, "valueOf",
                                          EnumValueDescriptor.class);
        this.enumGetValueDescriptor =
            getMethodOrDie(singularType, "getValueDescriptor");
      } else {
        this.enumValueOf = null;
        this.enumGetValueDescriptor = null;
      }
    }

    /** For use by generated code only. */
    public void internalInit(final FieldDescriptor descriptor) {
      if (descriptorRetriever != null) {
        throw new IllegalStateException("Already initialized.");
      }
      descriptorRetriever = new ExtensionDescriptorRetriever() {
          //@Override (Java 1.6 override semantics, but we must support 1.5)
          public FieldDescriptor getDescriptor() {
            return descriptor;
          }
        };
    }

    private ExtensionDescriptorRetriever descriptorRetriever;
    private final Class singularType;
    private final Message messageDefaultInstance;
    private final Method enumValueOf;
    private final Method enumGetValueDescriptor;

    public FieldDescriptor getDescriptor() {
      if (descriptorRetriever == null) {
        throw new IllegalStateException(
            "getDescriptor() called before internalInit()");
      }
      return descriptorRetriever.getDescriptor();
    }

    /**
     * If the extension is an embedded message or group, returns the default
     * instance of the message.
     */
    public Message getMessageDefaultInstance() {
      return messageDefaultInstance;
    }

    /**
     * Convert from the type used by the reflection accessors to the type used
     * by native accessors.  E.g., for enums, the reflection accessors use
     * EnumValueDescriptors but the native accessors use the generated enum
     * type.
     */
    @SuppressWarnings("unchecked")
    private Object fromReflectionType(final Object value) {
      FieldDescriptor descriptor = getDescriptor();
      if (descriptor.isRepeated()) {
        if (descriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE ||
            descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
          // Must convert the whole list.
          final List result = new ArrayList();
          for (final Object element : (List) value) {
            result.add(singularFromReflectionType(element));
          }
          return result;
        } else {
          return value;
        }
      } else {
        return singularFromReflectionType(value);
      }
    }

    /**
     * Like {@link #fromReflectionType(Object)}, but if the type is a repeated
     * type, this converts a single element.
     */
    private Object singularFromReflectionType(final Object value) {
      FieldDescriptor descriptor = getDescriptor();
      switch (descriptor.getJavaType()) {
        case MESSAGE:
          if (singularType.isInstance(value)) {
            return value;
          } else {
            // It seems the copy of the embedded message stored inside the
            // extended message is not of the exact type the user was
            // expecting.  This can happen if a user defines a
            // GeneratedExtension manually and gives it a different type.
            // This should not happen in normal use.  But, to be nice, we'll
            // copy the message to whatever type the caller was expecting.
            return messageDefaultInstance.newBuilderForType()
                           .mergeFrom((Message) value).build();
          }
        case ENUM:
          return invokeOrDie(enumValueOf, null, (EnumValueDescriptor) value);
        default:
          return value;
      }
    }

    /**
     * Convert from the type used by the native accessors to the type used
     * by reflection accessors.  E.g., for enums, the reflection accessors use
     * EnumValueDescriptors but the native accessors use the generated enum
     * type.
     */
    @SuppressWarnings("unchecked")
    private Object toReflectionType(final Object value) {
      FieldDescriptor descriptor = getDescriptor();
      if (descriptor.isRepeated()) {
        if (descriptor.getJavaType() == FieldDescriptor.JavaType.ENUM) {
          // Must convert the whole list.
          final List result = new ArrayList();
          for (final Object element : (List) value) {
            result.add(singularToReflectionType(element));
          }
          return result;
        } else {
          return value;
        }
      } else {
        return singularToReflectionType(value);
      }
    }

    /**
     * Like {@link #toReflectionType(Object)}, but if the type is a repeated
     * type, this converts a single element.
     */
    private Object singularToReflectionType(final Object value) {
      FieldDescriptor descriptor = getDescriptor();
      switch (descriptor.getJavaType()) {
        case ENUM:
          return invokeOrDie(enumGetValueDescriptor, value);
        default:
          return value;
      }
    }
  }

  // =================================================================

  /** Calls Class.getMethod and throws a RuntimeException if it fails. */
  @SuppressWarnings("unchecked")
  private static Method getMethodOrDie(
      final Class clazz, final String name, final Class... params) {
    try {
      return clazz.getMethod(name, params);
    } catch (NoSuchMethodException e) {
      throw new RuntimeException(
        "Generated message class \"" + clazz.getName() +
        "\" missing method \"" + name + "\".", e);
    }
  }

  /** Calls invoke and throws a RuntimeException if it fails. */
  private static Object invokeOrDie(
      final Method method, final Object object, final Object... params) {
    try {
      return method.invoke(object, params);
    } catch (IllegalAccessException e) {
      throw new RuntimeException(
        "Couldn't use Java reflection to implement protocol message " +
        "reflection.", e);
    } catch (InvocationTargetException e) {
      final Throwable cause = e.getCause();
      if (cause instanceof RuntimeException) {
        throw (RuntimeException) cause;
      } else if (cause instanceof Error) {
        throw (Error) cause;
      } else {
        throw new RuntimeException(
          "Unexpected exception thrown by generated accessor method.", cause);
      }
    }
  }

  /**
   * Users should ignore this class.  This class provides the implementation
   * with access to the fields of a message object using Java reflection.
   */
  public static final class FieldAccessorTable {

    /**
     * Construct a FieldAccessorTable for a particular message class.  Only
     * one FieldAccessorTable should ever be constructed per class.
     *
     * @param descriptor     The type's descriptor.
     * @param camelCaseNames The camelcase names of all fields in the message.
     *                       These are used to derive the accessor method names.
     * @param messageClass   The message type.
     * @param builderClass   The builder type.
     */
    public FieldAccessorTable(
        final Descriptor descriptor,
        final String[] camelCaseNames,
        final Class<? extends GeneratedMessage> messageClass,
        final Class<? extends Builder> builderClass) {
      this(descriptor, camelCaseNames);
      ensureFieldAccessorsInitialized(messageClass, builderClass);
    }

    /**
     * Construct a FieldAccessorTable for a particular message class without
     * initializing FieldAccessors.
     */
    public FieldAccessorTable(
        final Descriptor descriptor,
        final String[] camelCaseNames) {
      this.descriptor = descriptor;
      this.camelCaseNames = camelCaseNames;
      fields = new FieldAccessor[descriptor.getFields().size()];
      initialized = false;
    }

    /**
     * Ensures the field accessors are initialized. This method is thread-safe.
     *
     * @param messageClass   The message type.
     * @param builderClass   The builder type.
     * @return this
     */
    public FieldAccessorTable ensureFieldAccessorsInitialized(
        Class<? extends GeneratedMessage> messageClass,
        Class<? extends Builder> builderClass) {
      if (initialized) { return this; }
      synchronized (this) {
        if (initialized) { return this; }
        for (int i = 0; i < fields.length; i++) {
          FieldDescriptor field = descriptor.getFields().get(i);
          if (field.isRepeated()) {
            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
              fields[i] = new RepeatedMessageFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
              fields[i] = new RepeatedEnumFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            } else {
              fields[i] = new RepeatedFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            }
          } else {
            if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
              fields[i] = new SingularMessageFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            } else if (field.getJavaType() == FieldDescriptor.JavaType.ENUM) {
              fields[i] = new SingularEnumFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            } else {
              fields[i] = new SingularFieldAccessor(
                  field, camelCaseNames[i], messageClass, builderClass);
            }
          }
        }
        initialized = true;
        camelCaseNames = null;
        return this;
      }
    }

    private final Descriptor descriptor;
    private final FieldAccessor[] fields;
    private String[] camelCaseNames;
    private volatile boolean initialized;

    /** Get the FieldAccessor for a particular field. */
    private FieldAccessor getField(final FieldDescriptor field) {
      if (field.getContainingType() != descriptor) {
        throw new IllegalArgumentException(
          "FieldDescriptor does not match message type.");
      } else if (field.isExtension()) {
        // If this type had extensions, it would subclass ExtendableMessage,
        // which overrides the reflection interface to handle extensions.
        throw new IllegalArgumentException(
          "This type does not have extensions.");
      }
      return fields[field.getIndex()];
    }

    /**
     * Abstract interface that provides access to a single field.  This is
     * implemented differently depending on the field type and cardinality.
     */
    private interface FieldAccessor {
      Object get(GeneratedMessage message);
      Object get(GeneratedMessage.Builder builder);
      void set(Builder builder, Object value);
      Object getRepeated(GeneratedMessage message, int index);
      Object getRepeated(GeneratedMessage.Builder builder, int index);
      void setRepeated(Builder builder,
                       int index, Object value);
      void addRepeated(Builder builder, Object value);
      boolean has(GeneratedMessage message);
      boolean has(GeneratedMessage.Builder builder);
      int getRepeatedCount(GeneratedMessage message);
      int getRepeatedCount(GeneratedMessage.Builder builder);
      void clear(Builder builder);
      Message.Builder newBuilder();
      Message.Builder getBuilder(GeneratedMessage.Builder builder);
    }

    // ---------------------------------------------------------------

    private static class SingularFieldAccessor implements FieldAccessor {
      SingularFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        getMethod = getMethodOrDie(messageClass, "get" + camelCaseName);
        getMethodBuilder = getMethodOrDie(builderClass, "get" + camelCaseName);
        type = getMethod.getReturnType();
        setMethod = getMethodOrDie(builderClass, "set" + camelCaseName, type);
        hasMethod =
            getMethodOrDie(messageClass, "has" + camelCaseName);
        hasMethodBuilder =
            getMethodOrDie(builderClass, "has" + camelCaseName);
        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
      }

      // Note:  We use Java reflection to call public methods rather than
      //   access private fields directly as this avoids runtime security
      //   checks.
      protected final Class<?> type;
      protected final Method getMethod;
      protected final Method getMethodBuilder;
      protected final Method setMethod;
      protected final Method hasMethod;
      protected final Method hasMethodBuilder;
      protected final Method clearMethod;

      public Object get(final GeneratedMessage message) {
        return invokeOrDie(getMethod, message);
      }
      public Object get(GeneratedMessage.Builder builder) {
        return invokeOrDie(getMethodBuilder, builder);
      }
      public void set(final Builder builder, final Object value) {
        invokeOrDie(setMethod, builder, value);
      }
      public Object getRepeated(final GeneratedMessage message,
                                final int index) {
        throw new UnsupportedOperationException(
          "getRepeatedField() called on a singular field.");
      }
      public Object getRepeated(GeneratedMessage.Builder builder, int index) {
        throw new UnsupportedOperationException(
          "getRepeatedField() called on a singular field.");
      }
      public void setRepeated(final Builder builder,
                              final int index, final Object value) {
        throw new UnsupportedOperationException(
          "setRepeatedField() called on a singular field.");
      }
      public void addRepeated(final Builder builder, final Object value) {
        throw new UnsupportedOperationException(
          "addRepeatedField() called on a singular field.");
      }
      public boolean has(final GeneratedMessage message) {
        return (Boolean) invokeOrDie(hasMethod, message);
      }
      public boolean has(GeneratedMessage.Builder builder) {
        return (Boolean) invokeOrDie(hasMethodBuilder, builder);
      }
      public int getRepeatedCount(final GeneratedMessage message) {
        throw new UnsupportedOperationException(
          "getRepeatedFieldSize() called on a singular field.");
      }
      public int getRepeatedCount(GeneratedMessage.Builder builder) {
        throw new UnsupportedOperationException(
          "getRepeatedFieldSize() called on a singular field.");
      }
      public void clear(final Builder builder) {
        invokeOrDie(clearMethod, builder);
      }
      public Message.Builder newBuilder() {
        throw new UnsupportedOperationException(
          "newBuilderForField() called on a non-Message type.");
      }
      public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
        throw new UnsupportedOperationException(
          "getFieldBuilder() called on a non-Message type.");
      }
    }

    private static class RepeatedFieldAccessor implements FieldAccessor {
      protected final Class type;
      protected final Method getMethod;
      protected final Method getMethodBuilder;
      protected final Method getRepeatedMethod;
      protected final Method getRepeatedMethodBuilder;
      protected final Method setRepeatedMethod;
      protected final Method addRepeatedMethod;
      protected final Method getCountMethod;
      protected final Method getCountMethodBuilder;
      protected final Method clearMethod;

      RepeatedFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        getMethod = getMethodOrDie(messageClass,
                                   "get" + camelCaseName + "List");
        getMethodBuilder = getMethodOrDie(builderClass,
                                   "get" + camelCaseName + "List");
        getRepeatedMethod =
            getMethodOrDie(messageClass, "get" + camelCaseName, Integer.TYPE);
        getRepeatedMethodBuilder =
            getMethodOrDie(builderClass, "get" + camelCaseName, Integer.TYPE);
        type = getRepeatedMethod.getReturnType();
        setRepeatedMethod =
            getMethodOrDie(builderClass, "set" + camelCaseName,
                           Integer.TYPE, type);
        addRepeatedMethod =
            getMethodOrDie(builderClass, "add" + camelCaseName, type);
        getCountMethod =
            getMethodOrDie(messageClass, "get" + camelCaseName + "Count");
        getCountMethodBuilder =
            getMethodOrDie(builderClass, "get" + camelCaseName + "Count");

        clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
      }

      public Object get(final GeneratedMessage message) {
        return invokeOrDie(getMethod, message);
      }
      public Object get(GeneratedMessage.Builder builder) {
        return invokeOrDie(getMethodBuilder, builder);
      }
      public void set(final Builder builder, final Object value) {
        // Add all the elements individually.  This serves two purposes:
        // 1) Verifies that each element has the correct type.
        // 2) Insures that the caller cannot modify the list later on and
        //    have the modifications be reflected in the message.
        clear(builder);
        for (final Object element : (List<?>) value) {
          addRepeated(builder, element);
        }
      }
      public Object getRepeated(final GeneratedMessage message,
                                final int index) {
        return invokeOrDie(getRepeatedMethod, message, index);
      }
      public Object getRepeated(GeneratedMessage.Builder builder, int index) {
        return invokeOrDie(getRepeatedMethodBuilder, builder, index);
      }
      public void setRepeated(final Builder builder,
                              final int index, final Object value) {
        invokeOrDie(setRepeatedMethod, builder, index, value);
      }
      public void addRepeated(final Builder builder, final Object value) {
        invokeOrDie(addRepeatedMethod, builder, value);
      }
      public boolean has(final GeneratedMessage message) {
        throw new UnsupportedOperationException(
          "hasField() called on a repeated field.");
      }
      public boolean has(GeneratedMessage.Builder builder) {
        throw new UnsupportedOperationException(
          "hasField() called on a repeated field.");
      }
      public int getRepeatedCount(final GeneratedMessage message) {
        return (Integer) invokeOrDie(getCountMethod, message);
      }
      public int getRepeatedCount(GeneratedMessage.Builder builder) {
        return (Integer) invokeOrDie(getCountMethodBuilder, builder);
      }
      public void clear(final Builder builder) {
        invokeOrDie(clearMethod, builder);
      }
      public Message.Builder newBuilder() {
        throw new UnsupportedOperationException(
          "newBuilderForField() called on a non-Message type.");
      }
      public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
        throw new UnsupportedOperationException(
          "getFieldBuilder() called on a non-Message type.");
      }
    }

    // ---------------------------------------------------------------

    private static final class SingularEnumFieldAccessor
        extends SingularFieldAccessor {
      SingularEnumFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        super(descriptor, camelCaseName, messageClass, builderClass);

        valueOfMethod = getMethodOrDie(type, "valueOf",
                                       EnumValueDescriptor.class);
        getValueDescriptorMethod =
          getMethodOrDie(type, "getValueDescriptor");
      }

      private Method valueOfMethod;
      private Method getValueDescriptorMethod;

      @Override
      public Object get(final GeneratedMessage message) {
        return invokeOrDie(getValueDescriptorMethod, super.get(message));
      }

      @Override
      public Object get(final GeneratedMessage.Builder builder) {
        return invokeOrDie(getValueDescriptorMethod, super.get(builder));
      }

      @Override
      public void set(final Builder builder, final Object value) {
        super.set(builder, invokeOrDie(valueOfMethod, null, value));
      }
    }

    private static final class RepeatedEnumFieldAccessor
        extends RepeatedFieldAccessor {
      RepeatedEnumFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        super(descriptor, camelCaseName, messageClass, builderClass);

        valueOfMethod = getMethodOrDie(type, "valueOf",
                                       EnumValueDescriptor.class);
        getValueDescriptorMethod =
          getMethodOrDie(type, "getValueDescriptor");
      }

      private final Method valueOfMethod;
      private final Method getValueDescriptorMethod;

      @Override
      @SuppressWarnings("unchecked")
      public Object get(final GeneratedMessage message) {
        final List newList = new ArrayList();
        for (final Object element : (List) super.get(message)) {
          newList.add(invokeOrDie(getValueDescriptorMethod, element));
        }
        return Collections.unmodifiableList(newList);
      }

      @Override
      @SuppressWarnings("unchecked")
      public Object get(final GeneratedMessage.Builder builder) {
        final List newList = new ArrayList();
        for (final Object element : (List) super.get(builder)) {
          newList.add(invokeOrDie(getValueDescriptorMethod, element));
        }
        return Collections.unmodifiableList(newList);
      }

      @Override
      public Object getRepeated(final GeneratedMessage message,
                                final int index) {
        return invokeOrDie(getValueDescriptorMethod,
          super.getRepeated(message, index));
      }
      @Override
      public Object getRepeated(final GeneratedMessage.Builder builder,
                                final int index) {
        return invokeOrDie(getValueDescriptorMethod,
          super.getRepeated(builder, index));
      }
      @Override
      public void setRepeated(final Builder builder,
                              final int index, final Object value) {
        super.setRepeated(builder, index, invokeOrDie(valueOfMethod, null,
                          value));
      }
      @Override
      public void addRepeated(final Builder builder, final Object value) {
        super.addRepeated(builder, invokeOrDie(valueOfMethod, null, value));
      }
    }

    // ---------------------------------------------------------------

    private static final class SingularMessageFieldAccessor
        extends SingularFieldAccessor {
      SingularMessageFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        super(descriptor, camelCaseName, messageClass, builderClass);

        newBuilderMethod = getMethodOrDie(type, "newBuilder");
        getBuilderMethodBuilder =
            getMethodOrDie(builderClass, "get" + camelCaseName + "Builder");
      }

      private final Method newBuilderMethod;
      private final Method getBuilderMethodBuilder;

      private Object coerceType(final Object value) {
        if (type.isInstance(value)) {
          return value;
        } else {
          // The value is not the exact right message type.  However, if it
          // is an alternative implementation of the same type -- e.g. a
          // DynamicMessage -- we should accept it.  In this case we can make
          // a copy of the message.
          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
                  .mergeFrom((Message) value).buildPartial();
        }
      }

      @Override
      public void set(final Builder builder, final Object value) {
        super.set(builder, coerceType(value));
      }
      @Override
      public Message.Builder newBuilder() {
        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
      }
      @Override
      public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
        return (Message.Builder) invokeOrDie(getBuilderMethodBuilder, builder);
      }
    }

    private static final class RepeatedMessageFieldAccessor
        extends RepeatedFieldAccessor {
      RepeatedMessageFieldAccessor(
          final FieldDescriptor descriptor, final String camelCaseName,
          final Class<? extends GeneratedMessage> messageClass,
          final Class<? extends Builder> builderClass) {
        super(descriptor, camelCaseName, messageClass, builderClass);

        newBuilderMethod = getMethodOrDie(type, "newBuilder");
      }

      private final Method newBuilderMethod;

      private Object coerceType(final Object value) {
        if (type.isInstance(value)) {
          return value;
        } else {
          // The value is not the exact right message type.  However, if it
          // is an alternative implementation of the same type -- e.g. a
          // DynamicMessage -- we should accept it.  In this case we can make
          // a copy of the message.
          return ((Message.Builder) invokeOrDie(newBuilderMethod, null))
                  .mergeFrom((Message) value).build();
        }
      }

      @Override
      public void setRepeated(final Builder builder,
                              final int index, final Object value) {
        super.setRepeated(builder, index, coerceType(value));
      }
      @Override
      public void addRepeated(final Builder builder, final Object value) {
        super.addRepeated(builder, coerceType(value));
      }
      @Override
      public Message.Builder newBuilder() {
        return (Message.Builder) invokeOrDie(newBuilderMethod, null);
      }
    }
  }

  /**
   * Replaces this object in the output stream with a serialized form.
   * Part of Java's serialization magic.  Generated sub-classes must override
   * this method by calling {@code return super.writeReplace();}
   * @return a SerializedForm of this message
   */
  protected Object writeReplace() throws ObjectStreamException {
    return new GeneratedMessageLite.SerializedForm(this);
  }
}
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root/third_party/protobuf/java/src/main/java/com/google/protobuf/GeneratedMessage.java

DEFINITIONS
