    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}