ScopedHashMap.java

/*
 * Copyright 2013, 2014 Deutsche Nationalbibliothek
 *
 * 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.culturegraph.mf.commons.types;

import java.util.HashMap;

/**
 * @author "Markus Michael Geipel"
 *
 * @param <K>
 * @param <V>
 */
public final class ScopedHashMap<K, V> extends HashMap<K, V> {

	private static final long serialVersionUID = -7184066609960144713L;
	private final ScopedHashMap<K, V> outerScope;

	public ScopedHashMap(final ScopedHashMap<K, V> outerScope) {
		super();
		this.outerScope = outerScope;
	}

	public ScopedHashMap() {
		super();
		outerScope = null;
	}

	@Override
	public boolean containsKey(final Object key) {
		if (super.containsKey(key)) {
			return true;
		}
		return outerScope != null && outerScope.containsKey(key);
	}

	@Override
	public boolean containsValue(final Object value) {
		if (super.containsValue(value)) {
			return true;
		}
		return outerScope != null && outerScope.containsValue(value);
	}

	@Override
	public V get(final Object key) {
		final V ret = super.get(key);
		if (null == ret && outerScope != null) {
			return outerScope.get(key);
		}
		return ret;
	}

	public ScopedHashMap<K, V> getOuterScope() {
		return outerScope;
	}

	@Override
	public String toString() {
		return super.toString() + (getOuterScope() == null ? "" : "\n" + getOuterScope().toString());
	}
}