src/java/org/apache/commons/jelly/MapTagSupport.java

/*
 * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//jelly/src/java/org/apache/commons/jelly/MapTagSupport.java,v 1.5 2002/10/30 19:16:26 jstrachan Exp $
 * $Revision: 1.5 $
 * $Date: 2002/10/30 19:16:26 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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 OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 * 
 * $Id: MapTagSupport.java,v 1.5 2002/10/30 19:16:26 jstrachan Exp $
 */

package org.apache.commons.jelly;

import java.util.HashMap;

import java.util.Map;

/** 
 * <p><code>MapTag</code> is a DynaTag implementation which uses a Map
 * to store its attribute values in. Derived tags can then process this
 * Map, change values, add or remove attributes or perform some other form
 * of processsing pretty easily.
 * </p>
 *
 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
 * @version $Revision: 1.5 $
 */

public abstract class MapTagSupport extends DynaTagSupport {

    private Map map;

    /** Sets an attribute value of this tag before the tag is invoked
     */
    public void setAttribute(String name, Object value) {
        getAttributes().put(name, value);
    }

    /** 
     * Helper method which allows derived tags to access the attributes
     * associated with this tag
     */
    protected Map getAttributes() {
        if (map == null) {
            map = createAttributes();
        }
        return map;
    }
    /**
     * A Factory Method which allows derived tags to overload the Map
     * implementation used by this tag
     */

    protected Map createAttributes() {
        return new HashMap();
    }

}