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.Collection;
021
022import org.apache.commons.collections4.Closure;
023
024/**
025 * Closure implementation that chains the specified closures together.
026 *
027 * @since 3.0
028 * @version $Id: ChainedClosure.html 972421 2015-11-14 20:00:04Z tn $
029 */
030public class ChainedClosure<E> implements Closure<E>, Serializable {
031
032    /** Serial version UID */
033    private static final long serialVersionUID = -3520677225766901240L;
034
035    /** The closures to call in turn */
036    private final Closure<? super E>[] iClosures;
037
038    /**
039     * Factory method that performs validation and copies the parameter array.
040     *
041     * @param <E> the type that the closure acts on
042     * @param closures  the closures to chain, copied, no nulls
043     * @return the <code>chained</code> closure
044     * @throws IllegalArgumentException if the closures array is null
045     * @throws IllegalArgumentException if any closure in the array is null
046     */
047    public static <E> Closure<E> chainedClosure(final Closure<? super E>... closures) {
048        FunctorUtils.validate(closures);
049        if (closures.length == 0) {
050            return NOPClosure.<E>nopClosure();
051        }
052        return new ChainedClosure<E>(closures);
053    }
054
055    /**
056     * Create a new Closure that calls each closure in turn, passing the
057     * result into the next closure. The ordering is that of the iterator()
058     * method on the collection.
059     *
060     * @param <E> the type that the closure acts on
061     * @param closures  a collection of closures to chain
062     * @return the <code>chained</code> closure
063     * @throws IllegalArgumentException if the closures collection is null
064     * @throws IllegalArgumentException if any closure in the collection is null
065     */
066    @SuppressWarnings("unchecked")
067    public static <E> Closure<E> chainedClosure(final Collection<Closure<E>> closures) {
068        if (closures == null) {
069            throw new IllegalArgumentException("Closure collection must not be null");
070        }
071        if (closures.size() == 0) {
072            return NOPClosure.<E>nopClosure();
073        }
074        // convert to array like this to guarantee iterator() ordering
075        final Closure<? super E>[] cmds = new Closure[closures.size()];
076        int i = 0;
077        for (final Closure<? super E> closure : closures) {
078            cmds[i++] = closure;
079        }
080        FunctorUtils.validate(cmds);
081        return new ChainedClosure<E>(false, cmds);
082    }
083
084    /**
085     * Hidden constructor for the use by the static factory methods.
086     *
087     * @param clone  if {@code true} the input argument will be cloned
088     * @param closures  the closures to chain, no nulls
089     */
090    private ChainedClosure(final boolean clone, final Closure<? super E>... closures) {
091        super();
092        iClosures = clone ? FunctorUtils.copy(closures) : closures;
093    }
094
095    /**
096     * Constructor that performs no validation.
097     * Use <code>chainedClosure</code> if you want that.
098     *
099     * @param closures  the closures to chain, copied, no nulls
100     */
101    public ChainedClosure(final Closure<? super E>... closures) {
102        this(true, closures);
103    }
104
105    /**
106     * Execute a list of closures.
107     *
108     * @param input  the input object passed to each closure
109     */
110    public void execute(final E input) {
111        for (final Closure<? super E> iClosure : iClosures) {
112            iClosure.execute(input);
113        }
114    }
115
116    /**
117     * Gets the closures.
118     *
119     * @return a copy of the closures
120     * @since 3.1
121     */
122    public Closure<? super E>[] getClosures() {
123        return FunctorUtils.<E>copy(iClosures);
124    }
125
126}