001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.internal;
014
015import java.util.*;
016
017import org.apache.juneau.*;
018
019/**
020 * Represents a wrapped {@link Map} where entries in the map can be removed without affecting the underlying map.
021 *
022 * @param <T> The class type of the wrapped bean.
023 */
024public class DelegateMap<T> extends ObjectMap implements Delegate<T> {
025   private static final long serialVersionUID = 1L;
026
027   private transient ClassMeta<T> classMeta;
028
029   /**
030    * Constructor.
031    *
032    * @param classMeta The metadata object that created this delegate object.
033    */
034   public DelegateMap(ClassMeta<T> classMeta) {
035      this.classMeta = classMeta;
036   }
037
038   @Override /* Delegate */
039   public ClassMeta<T> getClassMeta() {
040      return classMeta;
041   }
042
043   /**
044    * Remove all but the specified keys from this map.
045    *
046    * <p>
047    * This does not affect the underlying map.
048    *
049    * @param keys The remaining keys in the map (in the specified order).
050    */
051   public void filterKeys(List<String> keys) {
052      ObjectMap m2 = new ObjectMap();
053      for (String k : keys)
054         m2.put(k, get(k));
055      this.clear();
056      this.putAll(m2);
057   }
058}