/* * Copyright 2012-2015 org.opencloudb. * * 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.opencloudb.config.util; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map.Entry; import java.util.Set; /** * @author mycat */ public class OrderRetainingMap<K, V> extends HashMap<K, V> { private static final long serialVersionUID = 1L; private Set<K> keyOrder = new ArraySet<K>(); private List<V> valueOrder = new ArrayList<V>(); @Override public V put(K key, V value) { keyOrder.add(key); valueOrder.add(value); return super.put(key, value); } @Override public Collection<V> values() { return Collections.unmodifiableList(valueOrder); } @Override public Set<K> keySet() { return Collections.unmodifiableSet(keyOrder); } @Override public Set<Entry<K, V>> entrySet() { throw new UnsupportedOperationException(); } /** * @author mycat */ private static class ArraySet<T> extends ArrayList<T> implements Set<T> { private static final long serialVersionUID = 1L; } }