src/main/java/com/google/devtools/build/lib/vfs/PathFragmentSerializationProxy.java

// Copyright 2014 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.vfs;

import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectOutput;


/**
 * A helper proxy for serializing immutable {@link PathFragment} objects.
 */
public final class PathFragmentSerializationProxy implements Externalizable {
  private String pathFragmentString;

  public PathFragmentSerializationProxy(String pathFragmentString) {
    this.pathFragmentString = pathFragmentString;
  }

  // For deserialization machinery.
  public PathFragmentSerializationProxy() {
  }

  @Override
  public void writeExternal(ObjectOutput out) throws IOException {
    // Manual serialization gives us about a 30% reduction in size.
    out.writeUTF(pathFragmentString);
  }

  @Override
  public void readExternal(java.io.ObjectInput in) throws IOException {
    this.pathFragmentString = in.readUTF();
  }

  private Object readResolve() {
    return new PathFragment(pathFragmentString);
  }
}