/* $Id: PathCallParamRule.java,v 1.8 2004/05/10 06:52:50 skitching Exp $
 *
 * Copyright 2003-2004 The Apache Software Foundation.
 * 
 * Licensed 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
 * 
 *      http://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.commons.digester;


import org.xml.sax.Attributes;

/**
 * <p>Rule implementation that saves a parameter containing the 
 * <code>Digester</code> matching path for use by a surrounding 
 * <code>CallMethodRule</code>. This Rule is most useful when making 
 * extensive use of wildcards in rule patterns.</p>
 *
 * @since 1.6
 */

public class PathCallParamRule extends Rule {

    // ----------------------------------------------------------- Constructors

    /**
     * Construct a "call parameter" rule that will save the body text of this
     * element as the parameter value.
     *
     * @param paramIndex The zero-relative parameter number
     */
    public PathCallParamRule(int paramIndex) {

        this.paramIndex = paramIndex;

    }
 
    // ----------------------------------------------------- Instance Variables

    /**
     * The zero-relative index of the parameter we are saving.
     */
    protected int paramIndex = 0;

    // --------------------------------------------------------- Public Methods


    /**
     * Process the start of this element.
     *
     * @param namespace the namespace URI of the matching element, or an 
     *   empty string if the parser is not namespace aware or the element has
     *   no namespace
     * @param name the local name if the parser is namespace aware, or just 
     *   the element name otherwise
     * @param attributes The attribute list for this element

     */
    public void begin(String namespace, String name, Attributes attributes) throws Exception {

        String param = getDigester().getMatch();
        
        if(param != null) {
            Object parameters[] = (Object[]) digester.peekParams();
            parameters[paramIndex] = param;
        }
        
    }

    /**
     * Render a printable version of this Rule.
     */
    public String toString() {

        StringBuffer sb = new StringBuffer("PathCallParamRule[");
        sb.append("paramIndex=");
        sb.append(paramIndex);
        sb.append("]");
        return (sb.toString());

    }
}