// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
// * to you 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                                                                             *
// *                                                                                                                         *
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// * specific language governing permissions and limitations under the License.                                              *
// ***************************************************************************************************************************
package org.apache.juneau.internal;

import static org.apache.juneau.internal.StringUtils.*;

import java.util.*;

import org.apache.juneau.*;
import org.apache.juneau.collections.*;

/**
 * Represents a wrapped {@link Map} where entries in the map can be removed without affecting the underlying map.
 *
 * <ul class='seealso'>
 * 	<li class='extlink'>{@source}
 * </ul>
 *
 * @param <T> The class type of the wrapped bean.
 * @serial exclude
 */
@SuppressWarnings("rawtypes")
public class DelegateMap<T extends Map> extends JsonMap implements Delegate<T> {
	private static final long serialVersionUID = 1L;

	private transient ClassMeta<T> classMeta;

	/**
	 * Constructor.
	 *
	 * @param m The metadata object that created this delegate object.
	 * @param session The current bean session.
	 */
	@SuppressWarnings("unchecked")
	public DelegateMap(T m, BeanSession session) {
		this.classMeta = session.getClassMetaForObject(m);
		m.forEach((k,v) -> put(stringify(k), v));
	}

	@Override /* Delegate */
	public ClassMeta<T> getClassMeta() {
		return classMeta;
	}

	/**
	 * Remove all but the specified keys from this map.
	 *
	 * <p>
	 * This does not affect the underlying map.
	 *
	 * @param keys The remaining keys in the map (in the specified order).
	 * @return This object.
	 */
	public DelegateMap<T> filterKeys(List<String> keys) {
		JsonMap m = new JsonMap();
		keys.forEach(k -> {
			if (containsKey(k))
				m.put(k, get(k));
		});
		this.clear();
		this.putAll(m);
		return this;
	}
}
