WaveletName.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.waveprotocol.wave.model.id;

import org.waveprotocol.wave.model.util.Preconditions;

import java.io.Serializable;

/**
 * A globally-unique wavelet identifier.
 *
 * A wavelet name is a tuple of a wave identifier and a wavelet identifier.
 *
 * @author anorth@google.com (Alex North)
 */
public class WaveletName implements Comparable<WaveletName>, Serializable {

  /**
   * The implementation of this class is subject to change, so {@code java.io}
   * serialization should only be used for short-term storage.
   */
  private static final long serialVersionUID = 0;

  public final WaveId waveId;
  public final WaveletId waveletId;

  /** Constructs a wavelet name for a wave id and wavelet id. */
  public static WaveletName of(WaveId waveId, WaveletId waveletId) {
    return new WaveletName(waveId, waveletId);
  }

  /** Constructs a wavelet name for wave and wavelet id components. */
  public static WaveletName of(String waveDomain, String waveId, String waveletDomain,
      String waveletId) {
    return new WaveletName(WaveId.of(waveDomain, waveId), WaveletId.of(waveletDomain, waveletId));
  }

  /** Private constructor to allow future instance optimisation. */
  private WaveletName(WaveId waveId, WaveletId waveletId) {
    if (waveId == null || waveletId == null) {
      Preconditions.nullPointer("Cannot create WaveletName with null value in [waveId:"
          + waveId + "] [waveletId:" + waveletId + "]");
    }
    this.waveId = waveId;
    this.waveletId = waveletId;
  }

  @Override
  public String toString() {
    return "[WaveletName " + ModernIdSerialiser.INSTANCE.serialiseWaveId(waveId)
        + "/" + ModernIdSerialiser.INSTANCE.serialiseWaveletId(waveletId) + "]";
  }

  @Override
  public boolean equals(Object other) {
    if (other instanceof WaveletName) {
      WaveletName o = (WaveletName) other;
      return waveId.equals(o.waveId) && waveletId.equals(o.waveletId);
    }
    return false;
  }

  @Override
  public int hashCode() {
    return waveId.hashCode() * 37 + waveletId.hashCode();
  }

  @Override
  public int compareTo(WaveletName o) {
    return waveId.equals(o.waveId) ? waveletId.compareTo(o.waveletId)
                                   : waveId.compareTo(o.waveId);
  }
}