    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 */
    029public class ChainedClosure<E> implements Closure<E>, Serializable {
    030
    031    /** Serial version UID */
    032    private static final long serialVersionUID = -3520677225766901240L;
    033
    034    /** The closures to call in turn */
    035    private final Closure<? super E>[] iClosures;
    036
    037    /**
    038     * Factory method that performs validation and copies the parameter array.
    039     *
    040     * @param <E> the type that the closure acts on
    041     * @param closures  the closures to chain, copied, no nulls
    042     * @return the <code>chained</code> closure
    043     * @throws NullPointerException if the closures array is null
    044     * @throws NullPointerException if any closure in the array is null
    045     */
    046    public static <E> Closure<E> chainedClosure(final Closure<? super E>... closures) {
    047        FunctorUtils.validate(closures);
    048        if (closures.length == 0) {
    049            return NOPClosure.<E>nopClosure();
    050        }
    051        return new ChainedClosure<>(closures);
    052    }
    053
    054    /**
    055     * Create a new Closure that calls each closure in turn, passing the
    056     * result into the next closure. The ordering is that of the iterator()
    057     * method on the collection.
    058     *
    059     * @param <E> the type that the closure acts on
    060     * @param closures  a collection of closures to chain
    061     * @return the <code>chained</code> closure
    062     * @throws NullPointerException if the closures collection is null
    063     * @throws NullPointerException if any closure in the collection is null
    064     */
    065    @SuppressWarnings("unchecked")
    066    public static <E> Closure<E> chainedClosure(final Collection<? extends Closure<? super E>> closures) {
    067        if (closures == null) {
    068            throw new NullPointerException("Closure collection must not be null");
    069        }
    070        if (closures.size() == 0) {
    071            return NOPClosure.<E>nopClosure();
    072        }
    073        // convert to array like this to guarantee iterator() ordering
    074        final Closure<? super E>[] cmds = new Closure[closures.size()];
    075        int i = 0;
    076        for (final Closure<? super E> closure : closures) {
    077            cmds[i++] = closure;
    078        }
    079        FunctorUtils.validate(cmds);
    080        return new ChainedClosure<>(false, cmds);
    081    }
    082
    083    /**
    084     * Hidden constructor for the use by the static factory methods.
    085     *
    086     * @param clone  if {@code true} the input argument will be cloned
    087     * @param closures  the closures to chain, no nulls
    088     */
    089    private ChainedClosure(final boolean clone, final Closure<? super E>... closures) {
    090        super();
    091        iClosures = clone ? FunctorUtils.copy(closures) : closures;
    092    }
    093
    094    /**
    095     * Constructor that performs no validation.
    096     * Use <code>chainedClosure</code> if you want that.
    097     *
    098     * @param closures  the closures to chain, copied, no nulls
    099     */
    100    public ChainedClosure(final Closure<? super E>... closures) {
    101        this(true, closures);
    102    }
    103
    104    /**
    105     * Execute a list of closures.
    106     *
    107     * @param input  the input object passed to each closure
    108     */
    109    @Override
    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}