de.dhke.projects.cutil.collections.MultiMapUtil.java Source code

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Here is the source code for de.dhke.projects.cutil.collections.MultiMapUtil.java

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/**
 * (c) 2009-2014 Peter Wullinger
 *
 * $Id$
 *
 * Use, modification and restribution of this file are covered by the
 * terms of the Artistic License 2.0.
 *
 * You should have received a copy of the license terms in a file named
 * "LICENSE" together with this software package.
 *
 * Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT
 * HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR
 * A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE
 * EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO
 * COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT
 * OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 */
package de.dhke.projects.cutil.collections;

import de.dhke.projects.cutil.collections.map.EmptyMultiMap;
import java.util.Collection;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections15.MultiMap;
import org.apache.commons.collections15.SetUtils;

/**
 *
 * @author Peter Wullinger <java@dhke.de>
 */
public final class MultiMapUtil {

    private MultiMapUtil() {
    }

    public static <K, V> boolean deepEquals(MultiMap<K, V> m1, MultiMap<? extends K, ? extends V> m2) {
        for (Map.Entry<K, Collection<V>> entry1 : m1.entrySet()) {
            if (!m2.containsKey(entry1.getKey()))
                return false;
            else {
                final Collection<? extends V> values2 = m2.get(entry1.getKey());
                if ((!entry1.getValue().containsAll(values2)) || (!values2.containsAll(entry1.getValue())))
                    return false;
            }
        }
        return m1.keySet().containsAll(m2.keySet());
    }

    public static <K, V> int deepHashCode(Map.Entry<K, Collection<V>> entry) {
        return entry.getKey().hashCode() + SetUtils.hashCodeForSet(entry.getValue());
    }

    public static <K, V> int deepHashCode(MultiMap<K, V> m) {
        int hashCode = 65537;
        for (Map.Entry<K, Collection<V>> entry : m.entrySet()) {
            hashCode += 7 * deepHashCode(entry);
        }
        return hashCode;
    }

    public static <V> Collection<V> getTransitive(final MultiMap<V, V> multiMap, final V key,
            final Collection<V> targetSet) {
        Collection<V> keyValues = multiMap.get(key);
        if (keyValues != null) {
            for (V keyValue : keyValues) {
                if (!targetSet.contains(keyValue)) {
                    targetSet.add(keyValue);
                    targetSet.addAll(getTransitive(multiMap, keyValue, targetSet));
                }
            }
        }
        return targetSet;
    }

    public static <V> Collection<V> getTransitive(final MultiMap<V, V> multiMap, final V key) {
        final Set<V> values = new HashSet<>();
        getTransitive(multiMap, key, values);

        return values;
    }

    public static <K, V> MultiMap<K, V> emptyMultiMap() {
        return new EmptyMultiMap<>();
    }
}