| /* |
| * Copyright 2003,2004 The Apache Software Foundation. |
| * |
| * Licensed 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. |
| * |
| * @version $Revision$ $Date$ |
| * @author Rodney Waldhoff |
| */ |
| public final class UnaryFunctionUnaryPredicate implements UnaryPredicate, Serializable { |
| /** |
| * Create an {@link UnaryPredicate UnaryPredicate} wrapping |
| * the given {@link UnaryFunction UnaryFunction}. |
| * @param function the {@link UnaryFunction UnaryFunction} to wrap |
| */ |
| public UnaryFunctionUnaryPredicate(UnaryFunction function) { |
| this.function = function; |
| } |
| |
| /** |
| * 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. |
| * |
| * @throws NullPointerException if my underlying function returns <code>null</code> |
| * @throws ClassCastException if my underlying function returns a non-<code>Boolean</code> |
| */ |
| public boolean test(Object obj) { |
| return ((Boolean)(function.evaluate(obj))).booleanValue(); |
| } |
| |
| public boolean equals(Object that) { |
| if(that instanceof UnaryFunctionUnaryPredicate) { |
| return equals((UnaryFunctionUnaryPredicate)that); |
| } else { |
| return false; |
| } |
| } |
| |
| public boolean equals(UnaryFunctionUnaryPredicate that) { |
| return that == this || (null != that && (null == function ? null == that.function : function.equals(that.function))); |
| } |
| |
| public int hashCode() { |
| int hash = "UnaryFunctionUnaryPredicate".hashCode(); |
| if(null != function) { |
| hash ^= function.hashCode(); |
| } |
| return hash; |
| } |
| |
| 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 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 UnaryFunctionUnaryPredicate adapt(UnaryFunction function) { |
| return null == function ? null : new UnaryFunctionUnaryPredicate(function); |
| } |
| |
| /** The {@link UnaryFunction UnaryFunction} I'm wrapping. */ |
| private UnaryFunction function = null; |
| } |