001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.collections4.functors;
018
019import java.io.Serializable;
020import java.util.Objects;
021
022import org.apache.commons.collections4.Closure;
023import org.apache.commons.collections4.Predicate;
024
025/**
026 * Closure implementation acts as an if statement calling one or other closure
027 * based on a predicate.
028 *
029 * @since 3.0
030 */
031public class IfClosure<E> implements Closure<E>, Serializable {
032
033    /** Serial version UID */
034    private static final long serialVersionUID = 3518477308466486130L;
035
036    /**
037     * Factory method that performs validation.
038     * <p>
039     * This factory creates a closure that performs no action when
040     * the predicate is false.
041     *
042     * @param <E> the type that the closure acts on
043     * @param predicate  predicate to switch on
044     * @param trueClosure  closure used if true
045     * @return the {@code if} closure
046     * @throws NullPointerException if either argument is null
047     * @since 3.2
048     */
049    public static <E> Closure<E> ifClosure(final Predicate<? super E> predicate, final Closure<? super E> trueClosure) {
050        return IfClosure.<E>ifClosure(predicate, trueClosure, NOPClosure.<E>nopClosure());
051    }
052    /**
053     * Factory method that performs validation.
054     *
055     * @param <E> the type that the closure acts on
056     * @param predicate  predicate to switch on
057     * @param trueClosure  closure used if true
058     * @param falseClosure  closure used if false
059     * @return the {@code if} closure
060     * @throws NullPointerException if any argument is null
061     */
062    public static <E> Closure<E> ifClosure(final Predicate<? super E> predicate,
063                                           final Closure<? super E> trueClosure,
064                                           final Closure<? super E> falseClosure) {
065        return new IfClosure<>(Objects.requireNonNull(predicate, "predicate"),
066                Objects.requireNonNull(trueClosure, "trueClosure"),
067                Objects.requireNonNull(falseClosure, "falseClosure"));
068    }
069    /** The test */
070    private final Predicate<? super E> iPredicate;
071
072    /** The closure to use if true */
073    private final Closure<? super E> iTrueClosure;
074
075    /** The closure to use if false */
076    private final Closure<? super E> iFalseClosure;
077
078    /**
079     * Constructor that performs no validation.
080     * Use {@code ifClosure} if you want that.
081     * <p>
082     * This constructor creates a closure that performs no action when
083     * the predicate is false.
084     *
085     * @param predicate  predicate to switch on, not null
086     * @param trueClosure  closure used if true, not null
087     * @since 3.2
088     */
089    public IfClosure(final Predicate<? super E> predicate, final Closure<? super E> trueClosure) {
090        this(predicate, trueClosure, NOPClosure.nopClosure());
091    }
092
093    /**
094     * Constructor that performs no validation.
095     * Use {@code ifClosure} if you want that.
096     *
097     * @param predicate  predicate to switch on, not null
098     * @param trueClosure  closure used if true, not null
099     * @param falseClosure  closure used if false, not null
100     */
101    public IfClosure(final Predicate<? super E> predicate, final Closure<? super E> trueClosure,
102                     final Closure<? super E> falseClosure) {
103        iPredicate = predicate;
104        iTrueClosure = trueClosure;
105        iFalseClosure = falseClosure;
106    }
107
108    /**
109     * Executes the true or false closure according to the result of the predicate.
110     *
111     * @param input  the input object
112     */
113    @Override
114    public void execute(final E input) {
115        if (iPredicate.evaluate(input)) {
116            iTrueClosure.execute(input);
117        } else {
118            iFalseClosure.execute(input);
119        }
120    }
121
122    /**
123     * Gets the closure called when false.
124     *
125     * @return the closure
126     * @since 3.1
127     */
128    public Closure<? super E> getFalseClosure() {
129        return iFalseClosure;
130    }
131
132    /**
133     * Gets the predicate.
134     *
135     * @return the predicate
136     * @since 3.1
137     */
138    public Predicate<? super E> getPredicate() {
139        return iPredicate;
140    }
141
142    /**
143     * Gets the closure called when true.
144     *
145     * @return the closure
146     * @since 3.1
147     */
148    public Closure<? super E> getTrueClosure() {
149        return iTrueClosure;
150    }
151
152}