IdFilters.java

/**
 * Copyright 2010 Google Inc.
 *
 * 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 org.waveprotocol.wave.model.id;

import java.util.Collections;

/**
 * This class contains a few static IdFilter instances and methods.
 *
 */
public class IdFilters {

  /** An id filter that accepts all ids. */
  public static final IdFilter ALL_IDS = IdFilter.of(
      Collections.<WaveletId>emptySet(), Collections.singleton(""));

  /** An IdFilter that accepts no ids. */
  public static final IdFilter NO_IDS = IdFilter.of(
      Collections.<WaveletId>emptySet(), Collections.<String>emptySet());

  /** An id filter that accepts only conversation wavelets. */
  public static final IdFilter CONVERSATION_WAVELET_IDS = IdFilter.ofPrefixes(
      IdUtil.CONVERSATION_WAVELET_PREFIX);

  protected IdFilters() {
    // hidden constructor
  }
}