| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| BoundFunction |
|
| 2.7142857142857144;2.714 |
| 1 | /* | |
| 2 | * Licensed to the Apache Software Foundation (ASF) under one or more | |
| 3 | * contributor license agreements. See the NOTICE file distributed with | |
| 4 | * this work for additional information regarding copyright ownership. | |
| 5 | * The ASF licenses this file to You under the Apache License, Version 2.0 | |
| 6 | * (the "License"); you may not use this file except in compliance with | |
| 7 | * the License. You may obtain a copy of the License at | |
| 8 | * | |
| 9 | * http://www.apache.org/licenses/LICENSE-2.0 | |
| 10 | * | |
| 11 | * Unless required by applicable law or agreed to in writing, software | |
| 12 | * distributed under the License is distributed on an "AS IS" BASIS, | |
| 13 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 14 | * See the License for the specific language governing permissions and | |
| 15 | * limitations under the License. | |
| 16 | */ | |
| 17 | package org.apache.commons.functor.adapter; | |
| 18 | ||
| 19 | import java.io.Serializable; | |
| 20 | ||
| 21 | import org.apache.commons.functor.Function; | |
| 22 | import org.apache.commons.functor.UnaryFunction; | |
| 23 | ||
| 24 | /** | |
| 25 | * Adapts a | |
| 26 | * {@link UnaryFunction UnaryFunction} | |
| 27 | * to the | |
| 28 | * {@link Function Function} interface | |
| 29 | * using a constant unary argument. | |
| 30 | * <p/> | |
| 31 | * Note that although this class implements | |
| 32 | * {@link Serializable}, a given instance will | |
| 33 | * only be truly <code>Serializable</code> if the | |
| 34 | * underlying objects are. Attempts to serialize | |
| 35 | * an instance whose delegates are not | |
| 36 | * <code>Serializable</code> will result in an exception. | |
| 37 | * | |
| 38 | * @param <T> the returned value type. | |
| 39 | * @version $Revision: 1157604 $ $Date: 2011-08-14 21:29:42 +0200 (Sun, 14 Aug 2011) $ | |
| 40 | * @author Rodney Waldhoff | |
| 41 | */ | |
| 42 | public final class BoundFunction<T> implements Function<T>, Serializable { | |
| 43 | /** | |
| 44 | * serialVersionUID declaration. | |
| 45 | */ | |
| 46 | private static final long serialVersionUID = 8873081237760986490L; | |
| 47 | /** The {@link UnaryFunction UnaryFunction} I'm wrapping. */ | |
| 48 | private final UnaryFunction<Object, ? extends T> function; | |
| 49 | /** The argument to pass to {@code function}. */ | |
| 50 | private final Object arg; | |
| 51 | ||
| 52 | /** | |
| 53 | * Create a new BoundFunction instance. | |
| 54 | * @param <A> the argument value type | |
| 55 | * @param function the function to adapt | |
| 56 | * @param arg the constant argument to use | |
| 57 | */ | |
| 58 | @SuppressWarnings("unchecked") | |
| 59 | 24 | public <A> BoundFunction(UnaryFunction<? super A, ? extends T> function, A arg) { |
| 60 | 24 | if (function == null) { |
| 61 | 0 | throw new IllegalArgumentException("UnaryFunction argument was null"); |
| 62 | } | |
| 63 | 24 | this.function = (UnaryFunction<Object, ? extends T>) function; |
| 64 | 24 | this.arg = arg; |
| 65 | 24 | } |
| 66 | ||
| 67 | /** | |
| 68 | * {@inheritDoc} | |
| 69 | */ | |
| 70 | public T evaluate() { | |
| 71 | 2 | return function.evaluate(arg); |
| 72 | } | |
| 73 | ||
| 74 | /** | |
| 75 | * {@inheritDoc} | |
| 76 | */ | |
| 77 | public boolean equals(Object that) { | |
| 78 | 30 | return that == this || (that instanceof BoundFunction<?> && equals((BoundFunction<?>) that)); |
| 79 | } | |
| 80 | ||
| 81 | /** | |
| 82 | * Learn whether another BoundFunction is equal to this. | |
| 83 | * @param that BoundFunction to test | |
| 84 | * @return boolean | |
| 85 | */ | |
| 86 | public boolean equals(BoundFunction<?> that) { | |
| 87 | 22 | if (that == null) { |
| 88 | 0 | return false; |
| 89 | } | |
| 90 | 22 | if (!(that.function.equals(this.function))) { |
| 91 | 4 | return false; |
| 92 | } | |
| 93 | 18 | return that.arg == this.arg || that.arg != null && that.arg.equals(this.arg); |
| 94 | } | |
| 95 | ||
| 96 | /** | |
| 97 | * {@inheritDoc} | |
| 98 | */ | |
| 99 | public int hashCode() { | |
| 100 | 32 | int result = "BoundFunction".hashCode(); |
| 101 | 32 | result <<= 2; |
| 102 | 32 | result |= function.hashCode(); |
| 103 | 32 | result <<= 2; |
| 104 | 32 | return arg == null ? result : result | arg.hashCode(); |
| 105 | } | |
| 106 | ||
| 107 | /** | |
| 108 | * {@inheritDoc} | |
| 109 | */ | |
| 110 | public String toString() { | |
| 111 | 24 | return "BoundFunction<" + function.toString() + "(" + arg + ")>"; |
| 112 | } | |
| 113 | ||
| 114 | /** | |
| 115 | * Adapt the given, possibly-<code>null</code>, | |
| 116 | * {@link UnaryFunction UnaryFunction} to the | |
| 117 | * {@link Function Function} interface by binding | |
| 118 | * the specified <code>Object</code> as a constant | |
| 119 | * argument. | |
| 120 | * When the given <code>UnaryFunction</code> is <code>null</code>, | |
| 121 | * returns <code>null</code>. | |
| 122 | * @param <A> input type | |
| 123 | * @param <T> result type | |
| 124 | * @param function the possibly-<code>null</code> | |
| 125 | * {@link UnaryFunction UnaryFunction} to adapt | |
| 126 | * @param arg the object to bind as a constant argument | |
| 127 | * @return a <code>BoundFunction</code> wrapping the given | |
| 128 | * {@link UnaryFunction UnaryFunction}, or <code>null</code> | |
| 129 | * if the given <code>UnaryFunction</code> is <code>null</code> | |
| 130 | */ | |
| 131 | public static <A, T> BoundFunction<T> bind(UnaryFunction<? super A, ? extends T> function, A arg) { | |
| 132 | 6 | return null == function ? null : new BoundFunction<T>(function, arg); |
| 133 | } | |
| 134 | ||
| 135 | } |