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package org.apache.taglibs.standard.tag.common.xml;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.tagext.BodyTagSupport;
import javax.servlet.jsp.tagext.Tag;

import org.apache.taglibs.standard.resources.Resources;

/**
 * <p>Support for tag handlers for <param>, the XML parameter
 * subtag for <transformt<.</p>
 *
 * @see TransformSupport
 * @author Shawn Bayern
 */

public abstract class ParamSupport extends BodyTagSupport {

    //*********************************************************************
    // Protected state

    protected String name;                       // 'name' attribute
    protected Object value;                      // 'value' attribute

    //*********************************************************************
    // Constructor and initialization

    public ParamSupport() {
	super();
	init();
    }

    private void init() {
	name = null;
	value = null;
    }


    //*********************************************************************
    // Tag logic

    // simply send our name and value to our parent <transform> tag
    public int doEndTag() throws JspException {
	Tag t = findAncestorWithClass(this, TransformSupport.class);
	if (t == null)
	    throw new JspTagException(
		Resources.getMessage("PARAM_OUTSIDE_TRANSFORM"));
	TransformSupport parent = (TransformSupport) t;

	Object value = this.value;
	if (value == null) {
            if (bodyContent == null || bodyContent.getString() == null)
                value = "";
            else
                value = bodyContent.getString().trim();
        }
	parent.addParameter(name, value);
	return EVAL_PAGE;
    }

    // Releases any resources we may have (or inherit)
    public void release() {
	init();
    }
}