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

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspTagException;
import javax.servlet.jsp.jstl.sql.SQLExecutionTag;
import javax.servlet.jsp.tagext.BodyTagSupport;

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


/**
 * <p>Tag handler for &lt;Param&gt; in JSTL, used to set
 * parameter values for a SQL statement.</p>
 * 
 * @author Hans Bergsten
 */

public abstract class ParamTagSupport extends BodyTagSupport {
    protected Object value;

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

    @Override
    public int doEndTag() throws JspException {
	SQLExecutionTag parent = (SQLExecutionTag) 
	    findAncestorWithClass(this, SQLExecutionTag.class);
	if (parent == null) {
	    throw new JspTagException(
                Resources.getMessage("SQL_PARAM_OUTSIDE_PARENT"));
	}

	Object paramValue = null;
	if (value != null) {
	    paramValue = value;
        } else if (bodyContent != null) {
	    paramValue = bodyContent.getString().trim();
	    if (((String) paramValue).trim().length() == 0) {
		paramValue = null;
	    }
	}

	parent.addSQLParameter(paramValue);
	return EVAL_PAGE;
    }
}
