org.solovyev.common.collections.multimap.ObjectsChangedMapUpdater.java Source code

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Here is the source code for org.solovyev.common.collections.multimap.ObjectsChangedMapUpdater.java

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/*
 * Copyright 2013 serso aka se.solovyev
 *
 * 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.solovyev.common.collections.multimap;

import com.google.common.collect.Iterables;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.Collection;
import java.util.List;
import java.util.Map;

public class ObjectsChangedMapUpdater<K, V> implements ThreadSafeMultimap.MapUpdater<K, V> {

    @Nonnull
    private final Collection<V> changedObjects;

    public ObjectsChangedMapUpdater(@Nonnull V changedObject) {
        this.changedObjects = Arrays.asList(changedObject);
    }

    public ObjectsChangedMapUpdater(@Nonnull Collection<V> changedObjects) {
        this.changedObjects = changedObjects;
    }

    @Nullable
    @Override
    public Map<K, List<V>> update(@Nonnull Map<K, List<V>> map) {
        if (containsChangedObjects(map)) {
            Map<K, List<V>> result = ThreadSafeMultimap.copy(map);

            for (List<V> objects : result.values()) {
                for (int i = 0; i < objects.size(); i++) {
                    final V object = objects.get(i);
                    for (V changedObject : changedObjects) {
                        if (object.equals(changedObject)) {
                            objects.set(i, changedObject);
                        }
                    }
                }
            }

            return result;
        } else {
            return null;
        }

    }

    private boolean containsChangedObjects(@Nonnull Map<K, List<V>> map) {
        if (changedObjects.size() > 1) {
            return true;
        } else if (changedObjects.size() == 1) {
            final V changedObject = Iterables.getFirst(changedObjects, null);
            for (List<V> objects : map.values()) {
                if (objects.contains(changedObject)) {
                    return true;
                }
            }

            return false;
        } else {
            return false;
        }
    }
}