| /* |
| * 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.functor.adapter; |
| |
| import java.io.Serializable; |
| |
| import org.apache.commons.functor.UnaryFunction; |
| import org.apache.commons.functor.UnaryPredicate; |
| |
| /** |
| * Adapts a <code>Boolean</code>-valued |
| * {@link UnaryFunction UnaryFunction} |
| * to the {@link UnaryPredicate UnaryPredicate} |
| * interface. |
| * <p/> |
| * Note that although this class implements |
| * {@link Serializable}, a given instance will |
| * only be truly <code>Serializable</code> if the |
| * underlying function is. Attempts to serialize |
| * an instance whose delegate is not |
| * <code>Serializable</code> will result in an exception. |
| * |
| * @param <A> the argument type. |
| * @version $Revision$ $Date$ |
| * @author Rodney Waldhoff |
| */ |
| public final class UnaryFunctionUnaryPredicate<A> implements UnaryPredicate<A>, Serializable { |
| /** |
| * serialVersionUID declaration. |
| */ |
| private static final long serialVersionUID = -9211927278252224707L; |
| /** The {@link UnaryFunction UnaryFunction} I'm wrapping. */ |
| private final UnaryFunction<? super A, Boolean> function; |
| |
| /** |
| * Create an {@link UnaryPredicate UnaryPredicate} wrapping |
| * the given {@link UnaryFunction UnaryFunction}. |
| * @param function the {@link UnaryFunction UnaryFunction} to wrap |
| */ |
| public UnaryFunctionUnaryPredicate(UnaryFunction<? super A, Boolean> function) { |
| if (function == null) { |
| throw new IllegalArgumentException("UnaryFunction argument was null"); |
| } |
| this.function = function; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * Returns the <code>boolean</code> value of the non-<code>null</code> |
| * <code>Boolean</code> returned by the {@link UnaryFunction#evaluate evaluate} |
| * method of my underlying function. |
| */ |
| public boolean test(A obj) { |
| return function.evaluate(obj).booleanValue(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object that) { |
| return that == this |
| || (that instanceof UnaryFunctionUnaryPredicate<?> && equals((UnaryFunctionUnaryPredicate<?>) that)); |
| } |
| |
| /** |
| * Learn whether another UnaryFunctionUnaryPredicate is equal to this. |
| * @param that UnaryFunctionUnaryPredicate to test |
| * @return boolean |
| */ |
| public boolean equals(UnaryFunctionUnaryPredicate<?> that) { |
| return null != that && (null == function ? null == that.function : function.equals(that.function)); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int hashCode() { |
| int hash = "UnaryFunctionUnaryPredicate".hashCode(); |
| if (null != function) { |
| hash ^= function.hashCode(); |
| } |
| return hash; |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public String toString() { |
| return "UnaryFunctionUnaryPredicate<" + function + ">"; |
| } |
| |
| /** |
| * Adapt the given, possibly-<code>null</code>, |
| * {@link UnaryFunction UnaryFunction} to the |
| * {@link UnaryPredicate UnaryPredicate} interface. |
| * When the given <code>UnaryFunction</code> is <code>null</code>, |
| * returns <code>null</code>. |
| * |
| * @param <A> the argument type. |
| * @param function the possibly-<code>null</code> |
| * {@link UnaryFunction UnaryFunction} to adapt |
| * @return a {@link UnaryPredicate UnaryPredicate} wrapping the given |
| * {@link UnaryFunction UnaryFunction}, or <code>null</code> |
| * if the given <code>UnaryFunction</code> is <code>null</code> |
| */ |
| public static <A> UnaryFunctionUnaryPredicate<A> adapt(UnaryFunction<? super A, Boolean> function) { |
| return null == function ? null : new UnaryFunctionUnaryPredicate<A>(function); |
| } |
| |
| } |