/* |
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* Licensed to the Apache Software Foundation (ASF) under one or more |
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* contributor license agreements. See the NOTICE file distributed with |
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* this work for additional information regarding copyright ownership. |
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* The ASF licenses this file to You under the Apache License, Version 2.0 |
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* (the "License"); you may not use this file except in compliance with |
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* the License. You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package org.apache.commons.collections4.multimap; |
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import java.util.Iterator; |
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import java.util.Map; |
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import org.apache.commons.collections4.CollectionUtils; |
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import org.apache.commons.collections4.FluentIterable; |
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import org.apache.commons.collections4.MultiValuedMap; |
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import org.apache.commons.collections4.Transformer; |
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/** |
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* Decorates another <code>MultiValuedMap</code> to transform objects that are added. |
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* <p> |
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* This class affects the MultiValuedMap put methods. Thus objects must be |
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* removed or searched for using their transformed form. For example, if the |
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* transformation converts Strings to Integers, you must use the Integer form to |
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* remove objects. |
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* </p> |
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* <p> |
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* <strong>Note that TransformedMultiValuedMap is not synchronized and is not thread-safe.</strong> |
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* </p> |
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* |
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* @param <K> the type of the keys in this map |
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* @param <V> the type of the values in this map |
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* @since 4.1 |
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*/ |
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public class TransformedMultiValuedMap<K, V> extends AbstractMultiValuedMapDecorator<K, V> { |
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/** Serialization Version */ |
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private static final long serialVersionUID = 20150612L; |
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/** The key transformer */ |
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private final Transformer<? super K, ? extends K> keyTransformer; |
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/** The value transformer */ |
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private final Transformer<? super V, ? extends V> valueTransformer; |
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/** |
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* Factory method to create a transforming MultiValuedMap. |
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* <p> |
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* If there are any elements already in the map being decorated, they are |
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* NOT transformed. Contrast this with |
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* {@link #transformedMap(MultiValuedMap, Transformer, Transformer)}. |
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* |
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* @param <K> the key type |
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* @param <V> the value type |
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* @param map the MultiValuedMap to decorate, may not be null |
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* @param keyTransformer the transformer to use for key conversion, null means no conversion |
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* @param valueTransformer the transformer to use for value conversion, null means no conversion |
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* @return a new transformed MultiValuedMap |
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* @throws NullPointerException if map is null |
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*/ |
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public static <K, V> TransformedMultiValuedMap<K, V> transformingMap(final MultiValuedMap<K, V> map, |
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final Transformer<? super K, ? extends K> keyTransformer, |
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final Transformer<? super V, ? extends V> valueTransformer) { |
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return new TransformedMultiValuedMap<>(map, keyTransformer, valueTransformer); |
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} |
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/** |
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* Factory method to create a transforming MultiValuedMap that will |
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* transform existing contents of the specified map. |
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* <p> |
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* If there are any elements already in the map being decorated, they will |
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* be transformed by this method. Contrast this with |
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* {@link #transformingMap(MultiValuedMap, Transformer, Transformer)}. |
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* |
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* @param <K> the key type |
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* @param <V> the value type |
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* @param map the MultiValuedMap to decorate, may not be null |
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* @param keyTransformer the transformer to use for key conversion, null means no conversion |
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* @param valueTransformer the transformer to use for value conversion, null means no conversion |
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* @return a new transformed MultiValuedMap |
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* @throws NullPointerException if map is null |
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*/ |
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public static <K, V> TransformedMultiValuedMap<K, V> transformedMap(final MultiValuedMap<K, V> map, |
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final Transformer<? super K, ? extends K> keyTransformer, |
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final Transformer<? super V, ? extends V> valueTransformer) { |
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final TransformedMultiValuedMap<K, V> decorated = |
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new TransformedMultiValuedMap<>(map, keyTransformer, valueTransformer); |
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if (!map.isEmpty()) { |
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final MultiValuedMap<K, V> mapCopy = new ArrayListValuedHashMap<>(map); |
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decorated.clear(); |
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decorated.putAll(mapCopy); |
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} |
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return decorated; |
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} |
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// ----------------------------------------------------------------------- |
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/** |
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* Constructor that wraps (not copies). |
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* <p> |
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* If there are any elements already in the collection being decorated, they |
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* are NOT transformed. |
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* |
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* @param map the MultiValuedMap to decorate, may not be null |
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* @param keyTransformer the transformer to use for key conversion, null means no conversion |
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* @param valueTransformer the transformer to use for value conversion, null means no conversion |
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* @throws NullPointerException if map is null |
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*/ |
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protected TransformedMultiValuedMap(final MultiValuedMap<K, V> map, |
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final Transformer<? super K, ? extends K> keyTransformer, |
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final Transformer<? super V, ? extends V> valueTransformer) { |
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super(map); |
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this.keyTransformer = keyTransformer; |
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this.valueTransformer = valueTransformer; |
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} |
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/** |
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* Transforms a key. |
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* <p> |
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* The transformer itself may throw an exception if necessary. |
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* |
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* @param object the object to transform |
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* @return the transformed object |
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*/ |
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protected K transformKey(final K object) { |
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if (keyTransformer == null) { |
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return object; |
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} |
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return keyTransformer.transform(object); |
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} |
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/** |
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* Transforms a value. |
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* <p> |
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* The transformer itself may throw an exception if necessary. |
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* |
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* @param object the object to transform |
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* @return the transformed object |
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*/ |
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protected V transformValue(final V object) { |
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if (valueTransformer == null) { |
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return object; |
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} |
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return valueTransformer.transform(object); |
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} |
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@Override |
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public boolean put(final K key, final V value) { |
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return decorated().put(transformKey(key), transformValue(value)); |
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} |
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@Override |
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public boolean putAll(final K key, final Iterable<? extends V> values) { |
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if (values == null) { |
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throw new NullPointerException("Values must not be null."); |
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} |
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final Iterable<V> transformedValues = FluentIterable.of(values).transform(valueTransformer); |
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final Iterator<? extends V> it = transformedValues.iterator(); |
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return it.hasNext() && CollectionUtils.addAll(decorated().get(transformKey(key)), it); |
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} |
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@Override |
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public boolean putAll(final Map<? extends K, ? extends V> map) { |
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if (map == null) { |
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throw new NullPointerException("Map must not be null."); |
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} |
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boolean changed = false; |
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for (final Map.Entry<? extends K, ? extends V> entry : map.entrySet()) { |
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changed |= put(entry.getKey(), entry.getValue()); |
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} |
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return changed; |
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} |
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@Override |
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public boolean putAll(final MultiValuedMap<? extends K, ? extends V> map) { |
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if (map == null) { |
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throw new NullPointerException("Map must not be null."); |
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} |
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boolean changed = false; |
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for (final Map.Entry<? extends K, ? extends V> entry : map.entries()) { |
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changed |= put(entry.getKey(), entry.getValue()); |
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} |
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return changed; |
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} |
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} |