/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.commons.collections4.multimap;
import java.util.Iterator;
import java.util.Map;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.collections4.FluentIterable;
import org.apache.commons.collections4.MultiValuedMap;
import org.apache.commons.collections4.Transformer;
/**
* Decorates another <code>MultiValuedMap</code> to transform objects that are added.
* <p>
* This class affects the MultiValuedMap put methods. Thus objects must be
* removed or searched for using their transformed form. For example, if the
* transformation converts Strings to Integers, you must use the Integer form to
* remove objects.
* <p>
* <strong>Note that TransformedMultiValuedMap is not synchronized and is not thread-safe.</strong>
*
* @since 4.1
* @version $Id$
*/
public class TransformedMultiValuedMap<K, V> extends AbstractMultiValuedMapDecorator<K, V> {
/** Serialization Version */
private static final long serialVersionUID = 20150612L;
/** The key transformer */
private final Transformer<? super K, ? extends K> keyTransformer;
/** The value transformer */
private final Transformer<? super V, ? extends V> valueTransformer;
/**
* Factory method to create a transforming MultiValuedMap.
* <p>
* If there are any elements already in the map being decorated, they are
* NOT transformed. Contrast this with
* {@link #transformedMap(MultiValuedMap, Transformer, Transformer)}.
*
* @param <K> the key type
* @param <V> the value type
* @param map the MultiValuedMap to decorate, may not be null
* @param keyTransformer the transformer to use for key conversion, null means no conversion
* @param valueTransformer the transformer to use for value conversion, null means no conversion
* @return a new transformed MultiValuedMap
* @throws NullPointerException if map is null
*/
public static <K, V> TransformedMultiValuedMap<K, V> transformingMap(final MultiValuedMap<K, V> map,
final Transformer<? super K, ? extends K> keyTransformer,
final Transformer<? super V, ? extends V> valueTransformer) {
return new TransformedMultiValuedMap<K, V>(map, keyTransformer, valueTransformer);
}
/**
* Factory method to create a transforming MultiValuedMap that will
* transform existing contents of the specified map.
* <p>
* If there are any elements already in the map being decorated, they will
* be transformed by this method. Contrast this with
* {@link #transformingMap(MultiValuedMap, Transformer, Transformer)}.
*
* @param <K> the key type
* @param <V> the value type
* @param map the MultiValuedMap to decorate, may not be null
* @param keyTransformer the transformer to use for key conversion, null means no conversion
* @param valueTransformer the transformer to use for value conversion, null means no conversion
* @return a new transformed MultiValuedMap
* @throws NullPointerException if map is null
*/
public static <K, V> TransformedMultiValuedMap<K, V> transformedMap(final MultiValuedMap<K, V> map,
final Transformer<? super K, ? extends K> keyTransformer,
final Transformer<? super V, ? extends V> valueTransformer) {
final TransformedMultiValuedMap<K, V> decorated =
new TransformedMultiValuedMap<K, V>(map, keyTransformer, valueTransformer);
if (!map.isEmpty()) {
final MultiValuedMap<K, V> mapCopy = new ArrayListValuedHashMap<K, V>(map);
decorated.clear();
decorated.putAll(mapCopy);
}
return decorated;
}
// -----------------------------------------------------------------------
/**
* Constructor that wraps (not copies).
* <p>
* If there are any elements already in the collection being decorated, they
* are NOT transformed.
*
* @param map the MultiValuedMap to decorate, may not be null
* @param keyTransformer the transformer to use for key conversion, null means no conversion
* @param valueTransformer the transformer to use for value conversion, null means no conversion
* @throws NullPointerException if map is null
*/
protected TransformedMultiValuedMap(final MultiValuedMap<K, V> map,
final Transformer<? super K, ? extends K> keyTransformer,
final Transformer<? super V, ? extends V> valueTransformer) {
super(map);
this.keyTransformer = keyTransformer;
this.valueTransformer = valueTransformer;
}
/**
* Transforms a key.
* <p>
* The transformer itself may throw an exception if necessary.
*
* @param object the object to transform
* @return the transformed object
*/
protected K transformKey(final K object) {
if (keyTransformer == null) {
return object;
}
return keyTransformer.transform(object);
}
/**
* Transforms a value.
* <p>
* The transformer itself may throw an exception if necessary.
*
* @param object the object to transform
* @return the transformed object
*/
protected V transformValue(final V object) {
if (valueTransformer == null) {
return object;
}
return valueTransformer.transform(object);
}
@Override
public boolean put(final K key, final V value) {
return decorated().put(transformKey(key), transformValue(value));
}
@Override
public boolean putAll(final K key, final Iterable<? extends V> values) {
if (values == null) {
throw new NullPointerException("Values must not be null.");
}
final Iterable<V> transformedValues = FluentIterable.of(values).transform(valueTransformer);
final Iterator<? extends V> it = transformedValues.iterator();
return it.hasNext() && CollectionUtils.addAll(decorated().get(transformKey(key)), it);
}
@Override
public boolean putAll(final Map<? extends K, ? extends V> map) {
if (map == null) {
throw new NullPointerException("Map must not be null.");
}
boolean changed = false;
for (Map.Entry<? extends K, ? extends V> entry : map.entrySet()) {
changed |= put(entry.getKey(), entry.getValue());
}
return changed;
}
@Override
public boolean putAll(final MultiValuedMap<? extends K, ? extends V> map) {
if (map == null) {
throw new NullPointerException("Map must not be null.");
}
boolean changed = false;
for (Map.Entry<? extends K, ? extends V> entry : map.entries()) {
changed |= put(entry.getKey(), entry.getValue());
}
return changed;
}
}