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/*******************************************************************************
 * Copyright (C) PicoContainer Organization. All rights reserved.
 * ---------------------------------------------------------------------------
 * The software in this package is published under the terms of the BSD style
 * license a copy of which has been included with this distribution in the
 * LICENSE.txt file. 
 ******************************************************************************/
package org.picocontainer.script.groovy.nodes;

import java.util.Map;

import org.picocontainer.PicoContainer;
import org.picocontainer.script.ScriptedPicoContainerMarkupException;
import org.picocontainer.classname.ClassLoadingPicoContainer;

/**
 * Sometimes it is worthwhile to split apart node building into functions. For
 * example, you might want to group adding the domain object repositories (DAOs)
 * into a single function to make your composition script easier to maintain.
 * 
 * Unfortunately, normally this is not allowed under normal builder rules. If
 * you wish to separate code you must revert to standard picocontainer calling
 * systax.
 * 
 * 
 * This node corrects that deficiency.
 * 
 * 
 * With it you can perform: 
 * pico = builder.container(parent:parent) {
 *   component(....)
 *   //...
 * }
 * <br/>
 * //
 * 
 * Now add more to pico.
 * 
 * builder.append(container: pico) {
 *   component(....)
 *   //...
 * }
 * 
 * 
 * 
 * @author Michael Rimov
 */
@SuppressWarnings("serial")
public class AppendContainerNode extends AbstractBuilderNode {
    /**
     * Node name.
     */
    public static final String NODE_NAME = "append";

    /**
     * Supported Attribute (Required): 'container.' Reference to the container
     * we are going to append to.
     */
    public static final String CONTAINER = "container";

    /**
     * Constructs an append container node.
     */
    public AppendContainerNode() {
        super(NODE_NAME);
    }

    /**
     * Returns the container passed in as the "container" attribute.
     * 
     * @param current the current Object, unused.
     * @param attributes the Map of attributes, which must have the container
     *            attribute defined.
     * @return Object the passed in node builder.
     * @throws ScriptedPicoContainerMarkupException if the container attribute
     *             is not supplied.
     * @throws ClassCastException if the container node specified is not a
     *             ScriptedPicoContainer or PicoContainer
     */
    public Object createNewNode(final Object current, final Map attributes)
            throws ScriptedPicoContainerMarkupException, ClassCastException {
        if (!isAttribute(attributes, CONTAINER)) {
            throw new ScriptedPicoContainerMarkupException(NODE_NAME + " must have a container attribute");
        }

        Object attributeValue = attributes.get(CONTAINER);
        if (!(attributeValue instanceof ClassLoadingPicoContainer) && !(attributeValue instanceof PicoContainer)) {
            throw new ClassCastException(attributeValue.toString()
                    + " must be a derivative of ScriptedPicoContainer or PicoContainer.  Got: "
                    + attributeValue.getClass().getName() + " instead.");
        }
        return attributeValue;
    }

}