content: // Protocol Buffers - Google's data interchange format
  // Copyright 2008 Google Inc.  All rights reserved.
  // https://developers.google.com/protocol-buffers/
  //
  // 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.
  
  // TODO(kenton):  Use generics?  E.g. Builder<BuilderType extends Builder>, then
  //   mergeFrom*() could return BuilderType for better type-safety.
  
  package com.google.protobuf;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.util.Map;
  
  /**
   * Abstract interface implemented by Protocol Message objects.
   *
   * <p>See also {@link MessageLite}, which defines most of the methods that typical users care about.
   * {@link Message} adds to it methods that are not available in the "lite" runtime. The biggest
   * added features are introspection and reflection -- i.e., getting descriptors for the message type
   * and accessing the field values dynamically.
   *
   * @author kenton@google.com Kenton Varda
   */
  public interface Message extends MessageLite, MessageOrBuilder {
  
    // (From MessageLite, re-declared here only for return type covariance.)
    @Override
    Parser<? extends Message> getParserForType();
  
  
    // -----------------------------------------------------------------
    // Comparison and hashing
  
    /**
     * Compares the specified object with this message for equality. Returns {@code true} if the given
     * object is a message of the same type (as defined by {@code getDescriptorForType()}) and has
     * identical values for all of its fields. Subclasses must implement this; inheriting {@code
     * Object.equals()} is incorrect.
     *
     * @param other object to be compared for equality with this message
     * @return {@code true} if the specified object is equal to this message
     */
    @Override
    boolean equals(Object other);
  
    /**
     * Returns the hash code value for this message. The hash code of a message should mix the
     * message's type (object identity of the descriptor) with its contents (known and unknown field
     * values). Subclasses must implement this; inheriting {@code Object.hashCode()} is incorrect.
     *
     * @return the hash code value for this message
     * @see Map#hashCode()
     */
    @Override
    int hashCode();
  
    // -----------------------------------------------------------------
    // Convenience methods.
  
    /**
     * Converts the message to a string in protocol buffer text format. This is just a trivial wrapper
     * around {@link TextFormat#printToString(MessageOrBuilder)}.
     */
    @Override
    String toString();
  
    // =================================================================
    // Builders
  
    // (From MessageLite, re-declared here only for return type covariance.)
    @Override
    Builder newBuilderForType();
  
    @Override
    Builder toBuilder();
  
    /** Abstract interface implemented by Protocol Message builders. */
    interface Builder extends MessageLite.Builder, MessageOrBuilder {
      // (From MessageLite.Builder, re-declared here only for return type
      // covariance.)
      @Override
      Builder clear();
  
      /**
       * Merge {@code other} into the message being built. {@code other} must have the exact same type
       * as {@code this} (i.e. {@code getDescriptorForType() == other.getDescriptorForType()}).
       *
       * <p>Merging occurs as follows. For each field:<br>
       * * For singular primitive fields, if the field is set in {@code other}, then {@code other}'s
       * value overwrites the value in this message.<br>
       * * For singular message fields, if the field is set in {@code other}, it is merged into the
       * corresponding sub-message of this message using the same merging rules.<br>
       * * For repeated fields, the elements in {@code other} are concatenated with the elements in
       * this message.<br>
       * * For oneof groups, if the other message has one of the fields set, the group of this message
       * is cleared and replaced by the field of the other message, so that the oneof constraint is
       * preserved.
       *
       * <p>This is equivalent to the {@code Message::MergeFrom} method in C++.
       */
      Builder mergeFrom(Message other);
  
      // (From MessageLite.Builder, re-declared here only for return type
      // covariance.)
      @Override
      Message build();
  
      @Override
      Message buildPartial();
  
      @Override
      Builder clone();
  
      @Override
      Builder mergeFrom(CodedInputStream input) throws IOException;
  
      @Override
      Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
          throws IOException;
  
      /** Get the message's type's descriptor. See {@link Message#getDescriptorForType()}. */
      @Override
      Descriptors.Descriptor getDescriptorForType();
  
      /**
       * Create a builder for messages of the appropriate type for the given field. The
       * builder is NOT nested in the current builder. However, messages built with the
       * builder can then be passed to the {@link #setField(Descriptors.FieldDescriptor, Object)},
       * {@link #setRepeatedField(Descriptors.FieldDescriptor, int, Object)}, or
       * {@link #addRepeatedField(Descriptors.FieldDescriptor, Object)}
       * method of the current builder.
       *
       * <p>To obtain a builder nested in the current builder, use
       * {@link #getFieldBuilder(Descriptors.FieldDescriptor)} instead.
       */
      Builder newBuilderForField(Descriptors.FieldDescriptor field);
  
      /**
       * Get a nested builder instance for the given field.
       *
       * <p>Normally, we hold a reference to the immutable message object for the message type field.
       * Some implementations(the generated message builders), however, can also hold a reference to
       * the builder object (a nested builder) for the field.
       *
       * <p>If the field is already backed up by a nested builder, the nested builder will be
       * returned. Otherwise, a new field builder will be created and returned. The original message
       * field (if exist) will be merged into the field builder, which will then be nested into its
       * parent builder.
       *
       * <p>NOTE: implementations that do not support nested builders will throw <code>
       * UnsupportedOperationException</code>.
       */
      Builder getFieldBuilder(Descriptors.FieldDescriptor field);
  
      /**
       * Get a nested builder instance for the given repeated field instance.
       *
       * <p>Normally, we hold a reference to the immutable message object for the message type field.
       * Some implementations(the generated message builders), however, can also hold a reference to
       * the builder object (a nested builder) for the field.
       *
       * <p>If the field is already backed up by a nested builder, the nested builder will be
       * returned. Otherwise, a new field builder will be created and returned. The original message
       * field (if exist) will be merged into the field builder, which will then be nested into its
       * parent builder.
       *
       * <p>NOTE: implementations that do not support nested builders will throw <code>
       * UnsupportedOperationException</code>.
       */
      Builder getRepeatedFieldBuilder(Descriptors.FieldDescriptor field, int index);
  
      /**
       * Sets a field to the given value. The value must be of the correct type for this field, i.e.
       * the same type that {@link Message#getField(Descriptors.FieldDescriptor)} would return.
       */
      Builder setField(Descriptors.FieldDescriptor field, Object value);
  
      /**
       * Clears the field. This is exactly equivalent to calling the generated "clear" accessor method
       * corresponding to the field.
       */
      Builder clearField(Descriptors.FieldDescriptor field);
  
      /**
       * Clears the oneof. This is exactly equivalent to calling the generated "clear" accessor method
       * corresponding to the oneof.
       */
      Builder clearOneof(Descriptors.OneofDescriptor oneof);
  
      /**
       * Sets an element of a repeated field to the given value. The value must be of the correct type
       * for this field, i.e. the same type that {@link
       * Message#getRepeatedField(Descriptors.FieldDescriptor,int)} would return.
       *
       * @throws IllegalArgumentException The field is not a repeated field, or {@code
       *     field.getContainingType() != getDescriptorForType()}.
       */
      Builder setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value);
  
      /**
       * Like {@code setRepeatedField}, but appends the value as a new element.
       *
       * @throws IllegalArgumentException The field is not a repeated field, or {@code
       *     field.getContainingType() != getDescriptorForType()}.
       */
      Builder addRepeatedField(Descriptors.FieldDescriptor field, Object value);
  
      /** Set the {@link UnknownFieldSet} for this message. */
      Builder setUnknownFields(UnknownFieldSet unknownFields);
  
      /** Merge some unknown fields into the {@link UnknownFieldSet} for this message. */
      Builder mergeUnknownFields(UnknownFieldSet unknownFields);
  
      // ---------------------------------------------------------------
      // Convenience methods.
  
      // (From MessageLite.Builder, re-declared here only for return type
      // covariance.)
      @Override
      Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
          throws InvalidProtocolBufferException;
  
      @Override
      Builder mergeFrom(InputStream input) throws IOException;
  
      @Override
      Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
          throws IOException;
  
      @Override
      boolean mergeDelimitedFrom(InputStream input) throws IOException;
  
      @Override
      boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
          throws IOException;
    }
  }
  