001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.juneau.internal;
018
019import java.util.*;
020
021import org.apache.juneau.*;
022import org.apache.juneau.collections.*;
023import org.apache.juneau.common.utils.*;
024
025/**
026 * Represents a wrapped {@link Map} where entries in the map can be removed without affecting the underlying map.
027 *
028 * <h5 class='section'>See Also:</h5><ul>
029
030 * </ul>
031 *
032 * @param <T> The class type of the wrapped bean.
033 * @serial exclude
034 */
035@SuppressWarnings("rawtypes")
036public class DelegateMap<T extends Map> extends JsonMap implements Delegate<T> {
037   private static final long serialVersionUID = 1L;
038
039   private transient ClassMeta<T> classMeta;
040
041   /**
042    * Constructor.
043    *
044    * @param m The metadata object that created this delegate object.
045    * @param session The current bean session.
046    */
047   @SuppressWarnings("unchecked")
048   public DelegateMap(T m, BeanSession session) {
049      this.classMeta = session.getClassMetaForObject(m);
050      m.forEach((k,v) -> put(Utils.s(k), v));
051   }
052
053   @Override /* Delegate */
054   public ClassMeta<T> getClassMeta() {
055      return classMeta;
056   }
057
058   /**
059    * Remove all but the specified keys from this map.
060    *
061    * <p>
062    * This does not affect the underlying map.
063    *
064    * @param keys The remaining keys in the map (in the specified order).
065    * @return This object.
066    */
067   public DelegateMap<T> filterKeys(List<String> keys) {
068      JsonMap m = new JsonMap();
069      keys.forEach(k -> {
070         if (containsKey(k))
071            m.put(k, get(k));
072      });
073      this.clear();
074      this.putAll(m);
075      return this;
076   }
077}