ELForwardTagHDIV.java

/**
 * Copyright 2005-2016 hdiv.org
 *
 * 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.hdiv.strutsel.taglib.logic;

import javax.servlet.jsp.JspException;

import org.apache.strutsel.taglib.utils.EvalHelper;
import org.hdiv.taglib.logic.ForwardTagHDIV;

/**
 * Perform a forward or redirect to a page that is looked up in the configuration information associated with our application.
 * <p>
 * This class is a subclass of the class <code>org.apache.struts.taglib.logix.ForwardTag</code> which provides most of the described
 * functionality. This subclass allows all attribute values to be specified as expressions utilizing the JavaServer Pages Standard Library
 * expression language.
 * 
 * @author Gorka Vicente
 * @since HDIV 2.0
 */
public class ELForwardTagHDIV extends ForwardTagHDIV {

	/**
	 * Instance variable mapped to "name" tag attribute. (Mapping set in associated BeanInfo class.)
	 */
	private String nameExpr;

	/**
	 * Getter method for "name" tag attribute. (Mapping set in associated BeanInfo class.)
	 */
	public String getNameExpr() {
		return (nameExpr);
	}

	/**
	 * Setter method for "name" tag attribute. (Mapping set in associated BeanInfo class.)
	 */
	public void setNameExpr(String nameExpr) {
		this.nameExpr = nameExpr;
	}

	/**
	 * Resets attribute values for tag reuse.
	 */
	public void release() {
		super.release();
		setNameExpr(null);
	}

	/**
	 * Process the start tag.
	 * 
	 * @throws JspException if a JSP exception has occurred
	 */
	public int doStartTag() throws JspException {
		evaluateExpressions();

		return (super.doStartTag());
	}

	/**
	 * Processes all attribute values which use the JSTL expression evaluation engine to determine their values.
	 * 
	 * @throws JspException if a JSP exception has occurred
	 */
	private void evaluateExpressions() throws JspException {
		String string = null;

		if ((string = EvalHelper.evalString("name", getNameExpr(), this, pageContext)) != null) {
			setName(string);
		}
	}
}