beantag.java

webwork source

/*
 * WebWork, Web Application Framework
 *
 * Distributable under Apache license.
 * See terms of license at opensource.org
 */
package webwork.view.taglib;

import webwork.util.BeanUtil;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import java.beans.Beans;

/**
 *	Instantiate a JavaBean.
 *
 * The bean may be an action, in which it is executed before used.
 * It is lazily executed, which means that you can set parameters
 * by using the "param" tag.
 *
 *	@author Rickard 謆erg ([e-mail])
 *	@version $Revision: 1.7 $
 */
public class BeanTag
   extends WebWorkTagSupport
   implements ParamTag.Parametric
{
   // Attributes ----------------------------------------------------
   protected String nameAttr;
   protected Object bean;

   // Public --------------------------------------------------------
	/**
	 * Set name of JavaBean class.
	 *
	 * @param aName class name
	 */
   public void setName(String aName)
   {
      nameAttr = aName;
   }

   /**
    * Set property in bean
    */
   public void addParameter(String name, Object value)
   {
      BeanUtil.setProperty(name, value, bean);
   }

   // BodyTag implementation ----------------------------------------
   public int doStartTag() throws JspException
   {
      // Instantiate bean
      ClassLoader cl = Thread.currentThread().getContextClassLoader();
      try
      {
         String name = (String)findValue(nameAttr);
         if (name == null)
            throw new JspException("No bean named "+nameAttr+" found. Try putting quotes around name");
         bean = Beans.instantiate(cl, name);
      } catch (Exception e)
      {
         try
         {
            pageContext.handlePageException(e);
         } catch (Exception ex)
         {
            // Ignore
         }
      }

      getStack().pushValue(bean);

      // Store as attribute?
      if(getId() != null)
      {
         pageContext.setAttribute(getId(), bean);
         pageContext.setAttribute(getId(), bean, PageContext.REQUEST_SCOPE);
      }

      return EVAL_BODY_INCLUDE;
   }

   public int doEndTag() throws JspException
   {
      getStack().popValue();
      return EVAL_PAGE;
   }
}