paramtag.java

webwork source

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

import javax.servlet.jsp.JspException;

/**
 * This tag can be used to parameterize other tags, who implement
 * the ParametricTag interface declared here.
 *
 * The IncludeTag and BeanTag are examples of such tags.
 *
 * @see IncludeTag
 * @see BeanTag
 * @author Rickard 謆erg ([e-mail])
 * @version $Revision: 1.7 $
 */
public class ParamTag
   extends WebWorkBodyTagSupport
{
   // Attributes ----------------------------------------------------
   protected String nameAttr;
   protected String valueAttr;

   public void setName(String aName)
   {
      nameAttr = aName;
   }

   public void setValue(String aName)
   {
      valueAttr = aName;
   }

   // BodyTag implementation ----------------------------------------
   public int doEndTag() throws JspException
   {
      Parametric parametricTag = (Parametric) TagUtil.findTagWithClass(this, Parametric.class);
      if(parametricTag != null)
      {
         if (valueAttr != null)
         {
            if (parametricTag instanceof UnnamedParametric)
               ((UnnamedParametric)parametricTag).addParameter(findValue(valueAttr));
            else
            {
               Object name = findValue(nameAttr);

               if (name == null)
               {
                  throw new JspException("No name found for following expression:"+nameAttr);
               }

               Object value = findValue(valueAttr);
               parametricTag.addParameter(name.toString(), value);
            }
         }
         else
         {
            String content;
            if (!(bodyContent != null && (content = bodyContent.getString()).length()!=0))
               content = null; // No value

            if (parametricTag instanceof UnnamedParametric)
               ((UnnamedParametric)parametricTag).addParameter(content);
            else
               parametricTag.addParameter(this.findString(nameAttr), content);
         }
      }
      return EVAL_PAGE;
   }

   // Inner classes -------------------------------------------------
   public interface Parametric
   {
      public void addParameter(String name, Object value);
   }

   public interface UnnamedParametric
     extends Parametric
   {
      public void addParameter(Object value);
   }
}