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/*
 * 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.collections4.functors;

import java.io.Serializable;
import java.util.Map;

import org.apache.commons.collections4.Closure;
import org.apache.commons.collections4.Predicate;

/**
 * Closure implementation calls the closure whose predicate returns true,
 * like a switch statement.
 *
 * @since 3.0
 * @version $Id: SwitchClosure.java 1686855 2015-06-22 13:00:27Z tn $
 */
public class SwitchClosure implements Closure, Serializable {

    /** Serial version UID */
    private static final long serialVersionUID = 3518477308466486130L;

    /** The tests to consider */
    private final Predicate[] iPredicates;
    /** The matching closures to call */
    private final Closure[] iClosures;
    /** The default closure to call if no tests match */
    private final Closure iDefault;

    /**
     * Factory method that performs validation and copies the parameter arrays.
     *
     * @param  the type that the closure acts on
     * @param predicates  array of predicates, cloned, no nulls
     * @param closures  matching array of closures, cloned, no nulls
     * @param defaultClosure  the closure to use if no match, null means nop
     * @return the chained closure
     * @throws NullPointerException if array is null
     * @throws NullPointerException if any element in the array is null
     * @throws IllegalArgumentException if the array lengths of predicates and closures do not match
     */
    @SuppressWarnings("unchecked")
    public static  Closure switchClosure(final Predicate[] predicates,
                                               final Closure[] closures,
                                               final Closure defaultClosure) {
        FunctorUtils.validate(predicates);
        FunctorUtils.validate(closures);
        if (predicates.length != closures.length) {
            throw new IllegalArgumentException("The predicate and closure arrays must be the same size");
        }
        if (predicates.length == 0) {
            return (Closure) (defaultClosure == null ? NOPClosure.nopClosure(): defaultClosure);
        }
        return new SwitchClosure(predicates, closures, defaultClosure);
    }

    /**
     * Create a new Closure that calls one of the closures depending
     * on the predicates.
     * 

* The Map consists of Predicate keys and Closure values. A closure * is called if its matching predicate returns true. Each predicate is evaluated * until one returns true. If no predicates evaluate to true, the default * closure is called. The default closure is set in the map with a * null key. The ordering is that of the iterator() method on the entryset * collection of the map. * * @param the type that the closure acts on * @param predicatesAndClosures a map of predicates to closures * @return the switch closure * @throws NullPointerException if the map is null * @throws NullPointerException if any closure in the map is null * @throws ClassCastException if the map elements are of the wrong type */ @SuppressWarnings("unchecked") public static Closure switchClosure(final Map, Closure> predicatesAndClosures) { if (predicatesAndClosures == null) { throw new NullPointerException("The predicate and closure map must not be null"); } // convert to array like this to guarantee iterator() ordering final Closure defaultClosure = predicatesAndClosures.remove(null); final int size = predicatesAndClosures.size(); if (size == 0) { return (Closure) (defaultClosure == null ? NOPClosure.nopClosure() : defaultClosure); } final Closure[] closures = new Closure[size]; final Predicate[] preds = new Predicate[size]; int i = 0; for (final Map.Entry, Closure> entry : predicatesAndClosures.entrySet()) { preds[i] = entry.getKey(); closures[i] = entry.getValue(); i++; } return new SwitchClosure(false, preds, closures, defaultClosure); } /** * Hidden constructor for the use by the static factory methods. * * @param clone if {@code true} the input arguments will be cloned * @param predicates array of predicates, no nulls * @param closures matching array of closures, no nulls * @param defaultClosure the closure to use if no match, null means nop */ @SuppressWarnings("unchecked") private SwitchClosure(final boolean clone, final Predicate[] predicates, final Closure[] closures, final Closure defaultClosure) { super(); iPredicates = clone ? FunctorUtils.copy(predicates) : predicates; iClosures = clone ? FunctorUtils.copy(closures) : closures; iDefault = (Closure) (defaultClosure == null ? NOPClosure.nopClosure() : defaultClosure); } /** * Constructor that performs no validation. * Use switchClosure if you want that. * * @param predicates array of predicates, cloned, no nulls * @param closures matching array of closures, cloned, no nulls * @param defaultClosure the closure to use if no match, null means nop */ public SwitchClosure(final Predicate[] predicates, final Closure[] closures, final Closure defaultClosure) { this(true, predicates, closures, defaultClosure); } /** * Executes the closure whose matching predicate returns true * * @param input the input object */ public void execute(final E input) { for (int i = 0; i < iPredicates.length; i++) { if (iPredicates[i].evaluate(input) == true) { iClosures[i].execute(input); return; } } iDefault.execute(input); } /** * Gets the predicates. * * @return a copy of the predicates * @since 3.1 */ public Predicate[] getPredicates() { return FunctorUtils.copy(iPredicates); } /** * Gets the closures. * * @return a copy of the closures * @since 3.1 */ public Closure[] getClosures() { return FunctorUtils.copy(iClosures); } /** * Gets the default closure. * * @return the default closure * @since 3.1 */ public Closure getDefaultClosure() { return iDefault; } }





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