CollectionUtils.java

/*******************************************************************************
 * Copyright (c) 2012-2015 Codenvy, S.A.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.ide.util;

import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * @author Vitaly Parfonov
 */
public class CollectionUtils {


    /**
     * Look up giving map for giving value collect pick all suitable keys
     * @param map
     * @param value
     * @return ste of keys mapped to the giving value
     */
    public static <T, E> Set<T> getKeysByValue(Map<T, E> map, E value) {
        Set<T> keys = new HashSet<T>();
        for (Map.Entry<T, E> entry : map.entrySet()) {
            if (value.equals(entry.getValue())) {
                keys.add(entry.getKey());
            }
        }
        return keys;
    }


    /**
     *
     * @param map
     * @param value
     * @return
     */
    public static <T, E> T getKeyByValue(Map<T, E> map, E value) {
        for (Map.Entry<T, E> entry : map.entrySet()) {
            if (value.equals(entry.getValue())) {
                return entry.getKey();
            }
        }
        return null;
    }
}