/*
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999-2002 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/>.
 * 
 */
package org.apache.commons.jelly.tags.core;

import java.io.IOException;
import java.io.Writer;
import java.util.List;

import org.apache.commons.jelly.JellyContext;
import org.apache.commons.jelly.JellyException;
import org.apache.commons.jelly.MissingAttributeException;
import org.apache.commons.jelly.Script;
import org.apache.commons.jelly.Tag;
import org.apache.commons.jelly.TagSupport;
import org.apache.commons.jelly.XMLOutput;
import org.apache.commons.jelly.expression.Expression;
import org.apache.commons.jelly.impl.ScriptBlock;

/** A tag which conditionally breaks out of the parent 
  *
  * @author <a href="mailto:vinayc@apache.org">Vinay Chandran</a>
  * @version $Revision: 1.0 $
  */
public class BreakTag extends TagSupport {

    /** The expression to evaluate. */
    private Expression ifExpr;

    public BreakTag() {
    }

    // Tag interface
    //------------------------------------------------------------------------- 
    public void doTag(XMLOutput output) throws Exception {
		Tag parentTag= getParent();
        
		if (ifExpr != null) {
            if (ifExpr.evaluateAsBoolean(getContext())) {
				//get hold of the parent tag 
				Script parentBody=parentTag.getBody();
				//clear the list of contained scripts within the parent
				if (parentBody instanceof ScriptBlock)
				{
					List containedScripts=((ScriptBlock)parentBody).getScriptList();
					synchronized(containedScripts)
					{
						containedScripts.clear();
					}
				}
            }
			else
			{
				invokeBody(output);				
			}
        }
        else {
            throw new MissingAttributeException( "if" );
        }

    }
    
    // Properties
    //-------------------------------------------------------------------------                
    /** Sets the Jelly expression to evaluate. If this returns true, we break out
     *   of the parent.
     * @param expr the Jelly expression to evaluate
     */
    public void setIf(Expression expr) {
        this.ifExpr = expr;
    }
}