WingMergeableElement.java

/*
 * WingMergeableElement.java
 *
 * Version: $Revision: 3705 $
 *
 * Date: $Date: 2009-04-11 17:02:24 +0000 (Sat, 11 Apr 2009) $
 *
 * Copyright (c) 2002-2005, Hewlett-Packard Company and Massachusetts
 * Institute of Technology.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Hewlett-Packard Company nor the name of the
 * Massachusetts Institute of Technology nor the names of their
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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 */

package org.dspace.app.xmlui.wing.element;

import org.dspace.app.xmlui.wing.WingException;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
 * This is an interface to represent all WingElements that can be merged.
 * 
 * @author Scott Phillips
 */

public interface WingMergeableElement extends WingElement
{

    /**
     * Determine if the given SAX startElement event is equivalent to this
     * WingElement.
     * 
     * @param namespace
     *            The element's name space
     * @param localName
     *            The local, unqualified, name for this element
     * @param qName
     *            The qualified name for this element
     * @param attributes
     *            The element's attributes
     * @return True if this WingElement is equivalent to the given SAX Event.
     */
    public boolean mergeEqual(String namespace, String localName, String qName,
            Attributes attributes) throws SAXException, WingException;

    /**
     * Merge the given SAX startElement event into this element's child. If this
     * SAX event matches a child element of this element then it should be
     * removed from the internal book keep of this element and returned.
     * typically this is accomplished by looping through all children elements
     * and returned the first one that returns true for the mergeEqual method.
     * 
     * @param namespace
     *            The element's name space
     * @param localName
     *            The local, unqualified, name for this element *
     * @param qName
     *            The qualified name for this element
     * @param attributes
     *            The element's attributes
     * @return The child element
     */
    public WingMergeableElement mergeChild(String namespace, String localName,
            String qName, Attributes attributes) throws SAXException,
            WingException;

    /**
     * Inform this element that it is being merged with an existing element.
     * Practically this means that when this method is being transformed to SAX it
     * should assume that the element's SAX events have all ready been sent. In
     * this case the element would only need to transform to SAX the children of
     * this element.
     * 
     * Further more if the element needs to add any attributes to the SAX
     * startElement event it may modify the attributes object passed to make
     * changes.
     * 
     * @return The attributes for this merged element
     */
    public Attributes merge(Attributes attributes) throws SAXException,
            WingException;
}