/* |
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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.functors; |
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import java.io.Serializable; |
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import org.apache.commons.collections4.Predicate; |
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import org.apache.commons.collections4.Transformer; |
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/** |
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* Predicate implementation that transforms the given object before invoking |
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* another <code>Predicate</code>. |
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* |
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* @since 3.1 |
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*/ |
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public final class TransformedPredicate<T> implements PredicateDecorator<T>, Serializable { |
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/** Serial version UID */ |
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private static final long serialVersionUID = -5596090919668315834L; |
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/** The transformer to call */ |
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private final Transformer<? super T, ? extends T> iTransformer; |
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/** The predicate to call */ |
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private final Predicate<? super T> iPredicate; |
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/** |
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* Factory to create the predicate. |
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* |
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* @param <T> the type that the predicate queries |
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* @param transformer the transformer to call |
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* @param predicate the predicate to call with the result of the transform |
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* @return the predicate |
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* @throws NullPointerException if the transformer or the predicate is null |
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*/ |
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public static <T> Predicate<T> transformedPredicate(final Transformer<? super T, ? extends T> transformer, |
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final Predicate<? super T> predicate) { |
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if (transformer == null) { |
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throw new NullPointerException("The transformer to call must not be null"); |
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} |
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if (predicate == null) { |
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throw new NullPointerException("The predicate to call must not be null"); |
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} |
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return new TransformedPredicate<>(transformer, predicate); |
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} |
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/** |
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* Constructor that performs no validation. |
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* Use <code>transformedPredicate</code> if you want that. |
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* |
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* @param transformer the transformer to use |
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* @param predicate the predicate to decorate |
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*/ |
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public TransformedPredicate(final Transformer<? super T, ? extends T> transformer, |
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final Predicate<? super T> predicate) { |
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iTransformer = transformer; |
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iPredicate = predicate; |
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} |
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/** |
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* Evaluates the predicate returning the result of the decorated predicate |
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* once the input has been transformed |
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* |
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* @param object the input object which will be transformed |
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* @return true if decorated predicate returns true |
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*/ |
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@Override |
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public boolean evaluate(final T object) { |
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final T result = iTransformer.transform(object); |
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return iPredicate.evaluate(result); |
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} |
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/** |
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* Gets the predicate being decorated. |
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* |
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* @return the predicate as the only element in an array |
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* @since 3.1 |
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*/ |
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@Override |
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@SuppressWarnings("unchecked") |
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public Predicate<? super T>[] getPredicates() { |
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return new Predicate[] {iPredicate}; |
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} |
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/** |
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* Gets the transformer in use. |
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* |
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* @return the transformer |
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*/ |
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public Transformer<? super T, ? extends T> getTransformer() { |
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return iTransformer; |
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} |
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} |