src/main/org/apache/tools/ant/util/ContainerMapper.java

/*
 *  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
 *
 *      https://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.tools.ant.util;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

import org.apache.tools.ant.types.Mapper;

/**
 * A <code>FileNameMapper</code> that contains
 * other <code>FileNameMapper</code>s.
 * @see FileNameMapper
 */
public abstract class ContainerMapper implements FileNameMapper {

    private List<FileNameMapper> mappers = new ArrayList<>();

    /**
     * Add a <code>Mapper</code>.
     * @param mapper the <code>Mapper</code> to add.
     */
    public void addConfiguredMapper(Mapper mapper) {
        add(mapper.getImplementation());
    }

    /**
     * An add configured version of the add method.
     * This class used to contain an add method and an
     * addConfiguredMapper method. Dur to ordering,
     * the add method was always called first. This
     * addConfigured method has been added to allow
     * chaining to work correctly.
     * @param fileNameMapper a <code>FileNameMapper</code>.
     */
    public void addConfigured(FileNameMapper fileNameMapper) {
        add(fileNameMapper);
    }

    /**
     * Add a <code>FileNameMapper</code>.
     * @param fileNameMapper a <code>FileNameMapper</code>.
     * @throws IllegalArgumentException if attempting to add this
     *         <code>ContainerMapper</code> to itself, or if the specified
     *         <code>FileNameMapper</code> is itself a <code>ContainerMapper</code>
     *         that contains this <code>ContainerMapper</code>.
     */
    public synchronized void add(FileNameMapper fileNameMapper) {
        if (this == fileNameMapper
            || (fileNameMapper instanceof ContainerMapper
            && ((ContainerMapper) fileNameMapper).contains(this))) {
            throw new IllegalArgumentException(
                "Circular mapper containment condition detected");
        }
        mappers.add(fileNameMapper);
    }

    /**
     * Return <code>true</code> if this <code>ContainerMapper</code> or any of
     * its sub-elements contains the specified <code>FileNameMapper</code>.
     * @param fileNameMapper   the <code>FileNameMapper</code> to search for.
     * @return <code>boolean</code>.
     */
    protected synchronized boolean contains(FileNameMapper fileNameMapper) {
        for (FileNameMapper m : mappers) {
            if (m == fileNameMapper) {
                return true;
            }
            if (m instanceof ContainerMapper
                && ((ContainerMapper) m).contains(fileNameMapper)) {
                return true;
            }
        }
        return false;
    }

    /**
     * Get the <code>List</code> of <code>FileNameMapper</code>s.
     * @return <code>List</code>.
     */
    public synchronized List<FileNameMapper> getMappers() {
        return Collections.unmodifiableList(mappers);
    }

    /**
     * Empty implementation.
     * @param ignore ignored.
     */
    @Override
    public void setFrom(String ignore) {
        //Empty
    }

    /**
     * Empty implementation.
     * @param ignore ignored.
     */
    @Override
    public void setTo(String ignore) {
        //Empty
    }

}