001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      https://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.bag;
018
019import java.util.Set;
020
021import org.apache.commons.collections4.Bag;
022import org.apache.commons.collections4.Transformer;
023import org.apache.commons.collections4.collection.TransformedCollection;
024import org.apache.commons.collections4.multiset.TransformedMultiSet;
025import org.apache.commons.collections4.set.TransformedSet;
026
027/**
028 * Decorates another {@link Bag} to transform objects that are added.
029 * <p>
030 * The add methods are affected by this class.
031 * Thus objects must be removed or searched for using their transformed form.
032 * For example, if the transformation converts Strings to Integers, you must
033 * use the Integer form to remove objects.
034 * </p>
035 * <p>
036 * This class is Serializable from Commons Collections 3.1.
037 * </p>
038 *
039 * @param <E> The type of elements in this bag
040 * @since 3.0
041 * @deprecated Since 4.6.0, use {@link TransformedMultiSet} instead.
042 */
043@Deprecated
044public class TransformedBag<E> extends TransformedCollection<E> implements Bag<E> {
045
046    /** Serialization version */
047    private static final long serialVersionUID = 5421170911299074185L;
048
049    /**
050     * Factory method to create a transforming bag that will transform
051     * existing contents of the specified bag.
052     * <p>
053     * If there are any elements already in the bag being decorated, they
054     * will be transformed by this method.
055     * Contrast this with {@link #transformingBag(Bag, Transformer)}.
056     *
057     * @param <E> The type of the elements in the bag
058     * @param bag  The bag to decorate, must not be null
059     * @param transformer  The transformer to use for conversion, must not be null
060     * @return A new transformed Bag
061     * @throws NullPointerException if bag or transformer is null
062     * @since 4.0
063     */
064    public static <E> Bag<E> transformedBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
065        final TransformedBag<E> decorated = new TransformedBag<>(bag, transformer);
066        if (!bag.isEmpty()) {
067            @SuppressWarnings("unchecked") // Bag is of type E
068            final E[] values = (E[]) bag.toArray(); // NOPMD - false positive for generics
069            bag.clear();
070            for (final E value : values) {
071                decorated.decorated().add(transformer.apply(value));
072            }
073        }
074        return decorated;
075    }
076
077    /**
078     * Factory method to create a transforming bag.
079     * <p>
080     * If there are any elements already in the bag being decorated, they
081     * are NOT transformed. Contrast this with {@link #transformedBag(Bag, Transformer)}.
082     *
083     * @param <E> The type of the elements in the bag
084     * @param bag  The bag to decorate, must not be null
085     * @param transformer  The transformer to use for conversion, must not be null
086     * @return A new transformed Bag
087     * @throws NullPointerException if bag or transformer is null
088     * @since 4.0
089     */
090    public static <E> Bag<E> transformingBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
091        return new TransformedBag<>(bag, transformer);
092    }
093
094    /**
095     * Constructor that wraps (not copies).
096     * <p>
097     * If there are any elements already in the bag being decorated, they
098     * are NOT transformed.
099     *
100     * @param bag  The bag to decorate, must not be null
101     * @param transformer  The transformer to use for conversion, must not be null
102     * @throws NullPointerException if bag or transformer is null
103     */
104    protected TransformedBag(final Bag<E> bag, final Transformer<? super E, ? extends E> transformer) {
105        super(bag, transformer);
106    }
107
108    @Override
109    public boolean add(final E object, final int nCopies) {
110        return getBag().add(transform(object), nCopies);
111    }
112
113    @Override
114    public boolean equals(final Object object) {
115        return object == this || decorated().equals(object);
116    }
117
118    /**
119     * Gets the decorated bag.
120     *
121     * @return The decorated bag
122     */
123    protected Bag<E> getBag() {
124        return (Bag<E>) decorated();
125    }
126
127    @Override
128    public int getCount(final Object object) {
129        return getBag().getCount(object);
130    }
131
132    @Override
133    public int hashCode() {
134        return decorated().hashCode();
135    }
136
137    @Override
138    public boolean remove(final Object object, final int nCopies) {
139        return getBag().remove(object, nCopies);
140    }
141
142    @Override
143    public Set<E> uniqueSet() {
144        final Set<E> set = getBag().uniqueSet();
145        return TransformedSet.<E>transformingSet(set, transformer);
146    }
147
148}