| /* |
| * 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 org.apache.commons.functor.BinaryFunction; |
| import org.apache.commons.functor.Function; |
| import org.apache.commons.lang3.Validate; |
| |
| /** |
| * Adapts a BinaryFunction as a Function by sending the same argument to both sides of the BinaryFunction. |
| * It sounds nonsensical, but using Composite functions, can be made to do something useful. |
| * @param <A> the argument type. |
| * @param <T> the returned value type. |
| * @version $Revision: 1345136 $ $Date: 2012-06-01 09:47:06 -0300 (Fri, 01 Jun 2012) $ |
| */ |
| public final class BinaryFunctionFunction<A, T> implements Function<A, T> { |
| /** |
| * The adapted function. |
| */ |
| private final BinaryFunction<? super A, ? super A, ? extends T> function; |
| |
| /** |
| * Create a new BinaryFunctionFunction. |
| * @param function to adapt |
| */ |
| public BinaryFunctionFunction(BinaryFunction<? super A, ? super A, ? extends T> function) { |
| this.function = Validate.notNull(function, "BinaryFunction argument was null"); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| public T evaluate(A obj) { |
| return function.evaluate(obj, obj); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public boolean equals(Object obj) { |
| return obj == this || obj instanceof BinaryFunctionFunction<?, ?> |
| && equals((BinaryFunctionFunction<?, ?>) obj); |
| } |
| |
| /** |
| * Learn whether another BinaryFunctionFunction is equal to <code>this</code>. |
| * @param that BinaryFunctionFunction to check |
| * @return whether equal |
| */ |
| public boolean equals(BinaryFunctionFunction<?, ?> that) { |
| return that != null && that.function.equals(this.function); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public int hashCode() { |
| return ("BinaryFunctionFunction".hashCode() << 2) | function.hashCode(); |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public String toString() { |
| return "BinaryFunctionFunction<" + function + ">"; |
| } |
| |
| /** |
| * Adapt a BinaryFunction as a Function. |
| * @param <A> input type |
| * @param <T> result type |
| * @param function to adapt |
| * @return Function<A, T> |
| */ |
| public static <A, T> Function<A, T> adapt(BinaryFunction<? super A, ? super A, ? extends T> function) { |
| return null == function ? null : new BinaryFunctionFunction<A, T>(function); |
| } |
| |
| } |