48 lines
2.0 KiB
Java
48 lines
2.0 KiB
Java
/**
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* Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] Licensed under the Apache License,
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* Version 2.0 (the "License"); you may not use this file except in compliance with the License. You
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* may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
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* applicable law or agreed to in writing, software distributed under the License is distributed on
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* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
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* the License for the specific language governing permissions and limitations under the License
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*/
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/**
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* Copyright [2009-2010] [dennis zhuang(killme2008@gmail.com)] Licensed under the Apache License,
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* Version 2.0 (the "License"); you may not use this file except in compliance with the License. You
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* may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by
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* applicable law or agreed to in writing, software distributed under the License is distributed on
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* an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
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* the License for the specific language governing permissions and limitations under the License
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*/
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package com.google.code.yanf4j.util;
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import java.util.Collection;
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import java.util.Set;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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/**
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* A {@link ConcurrentHashMap}-backed {@link Set}.
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*
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* @author The Apache MINA Project (dev@mina.apache.org)
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* @version $Rev: 597692 $, $Date: 2007-11-23 08:56:32 -0700 (Fri, 23 Nov 2007) $
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*/
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public class ConcurrentHashSet<E> extends MapBackedSet<E> {
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private static final long serialVersionUID = 8518578988740277828L;
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public ConcurrentHashSet() {
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super(new ConcurrentHashMap<E, Boolean>());
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}
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public ConcurrentHashSet(Collection<E> c) {
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super(new ConcurrentHashMap<E, Boolean>(), c);
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}
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@Override
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public boolean add(E o) {
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Boolean answer = ((ConcurrentMap<E, Boolean>) map).putIfAbsent(o, Boolean.TRUE);
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return answer == null;
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}
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}
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