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/*
* 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.set;
import java.util.Set;
import org.apache.commons.collections4.Transformer;
import org.apache.commons.collections4.collection.TransformedCollection;
/**
* Decorates another Set to transform objects that are added.
*
* The add methods are affected by this class.
* 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.
*
* This class is Serializable from Commons Collections 3.1.
*
* @param the type of the elements in this set
* @since 3.0
*/
public class TransformedSet extends TransformedCollection implements Set {
/** Serialization version */
private static final long serialVersionUID = 306127383500410386L;
/**
* Factory method to create a transforming set.
*
* If there are any elements already in the set being decorated, they
* are NOT transformed.
* Contrast this with {@link #transformedSet(Set, Transformer)}.
*
* @param the element type
* @param set the set to decorate, must not be null
* @param transformer the transformer to use for conversion, must not be null
* @return a new transformed set
* @throws NullPointerException if set or transformer is null
* @since 4.0
*/
public static TransformedSet transformingSet(final Set set,
final Transformer transformer) {
return new TransformedSet<>(set, transformer);
}
/**
* Factory method to create a transforming set that will transform
* existing contents of the specified set.
*
* If there are any elements already in the set being decorated, they
* will be transformed by this method.
* Contrast this with {@link #transformingSet(Set, Transformer)}.
*
* @param the element type
* @param set the set to decorate, must not be null
* @param transformer the transformer to use for conversion, must not be null
* @return a new transformed set
* @throws NullPointerException if set or transformer is null
* @since 4.0
*/
public static Set transformedSet(final Set set, final Transformer transformer) {
final TransformedSet decorated = new TransformedSet<>(set, transformer);
if (set.size() > 0) {
@SuppressWarnings("unchecked") // set is type E
final E[] values = (E[]) set.toArray(); // NOPMD - false positive for generics
set.clear();
for (final E value : values) {
decorated.decorated().add(transformer.transform(value));
}
}
return decorated;
}
//-----------------------------------------------------------------------
/**
* Constructor that wraps (not copies).
*
* If there are any elements already in the set being decorated, they
* are NOT transformed.
*
* @param set the set to decorate, must not be null
* @param transformer the transformer to use for conversion, must not be null
* @throws NullPointerException if set or transformer is null
*/
protected TransformedSet(final Set set, final Transformer transformer) {
super(set, transformer);
}
@Override
public boolean equals(final Object object) {
return object == this || decorated().equals(object);
}
@Override
public int hashCode() {
return decorated().hashCode();
}
}