/** * Copyright 2009 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.util; import java.util.Set; /** * @author danilatos@google.com (Daniel Danilatos) */ public class ChainedHashSet<T> extends ChainedData<Set<T>, Set<T>> { public static final ChainedHashSet<Object> EMPTY_ROOT = new ChainedHashSet<Object>(); @SuppressWarnings("unchecked") public static <T> ChainedHashSet<T> emptyRoot() { return (ChainedHashSet<T>) EMPTY_ROOT; } /** * Root */ public ChainedHashSet() { super(CollectionUtils.<T>hashSetDomain()); } /** * Chained */ public ChainedHashSet(ChainedHashSet<T> parent) { super(parent); } /** Create a child set */ public ChainedHashSet<T> createExtension() { return new ChainedHashSet<T>(this); } }