org.semanticweb.elk.util.collections.MultimapQueueImpl Maven / Gradle / Ivy

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/**
 * 
 */
package org.semanticweb.elk.util.collections;
/*
 * #%L
 * ELK Utilities Collections
 * $Id:$
 * $HeadURL:$
 * %%
 * Copyright (C) 2011 - 2014 Department of Computer Science, University of Oxford
 * %%
 * 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.
 * #L%
 */

import java.util.AbstractMap;
import java.util.Collection;
import java.util.Map.Entry;
import java.util.Set;

/**
 * Simple {@link MultimapQueue} backed by a {@link Multimap}.
 * 
 * @author Pavel Klinov
 *
 * [email protected]
 * 
 * @param 
 *            the keys of the multimap
 * @param 
 *            the values of the multimap 
 */
public class MultimapQueueImpl implements MultimapQueue {

	private final Multimap multimap_;
	
	public MultimapQueueImpl(Multimap multimap) {
		multimap_ = multimap;
	}
	
	@Override
	public boolean contains(Key key, Value value) {
		return multimap_.contains(key, value);
	}

	@Override
	public boolean add(Key key, Value value) {
		return multimap_.add(key, value);
	}

	@Override
	public Collection get(Key key) {
		return multimap_.get(key);
	}

	@Override
	public boolean remove(Object key, Object value) {
		return multimap_.remove(key, value);
	}

	@Override
	public Collection remove(Object key) {
		return multimap_.remove(key);
	}

	@Override
	public boolean isEmpty() {
		return multimap_.isEmpty();
	}

	@Override
	public Set keySet() {
		return multimap_.keySet();
	}

	@Override
	public void clear() {
		multimap_.clear();
	}

	@Override
	public Entry> takeEntry() {
		if (isEmpty()) {
			return null;
		}
		
		Key firstKey = keySet().iterator().next();
		
		return new AbstractMap.SimpleImmutableEntry>(firstKey, remove(firstKey));
	}

}