webworktagsupport.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.ServletValueStack;
import webwork.util.BeanUtil;
import webwork.action.ValidationEditorSupport;

import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;
import java.io.ByteArrayOutputStream;
import java.io.PrintWriter;
import java.beans.PropertyEditor;

/**
 * Base class for tags.
 *
 * @author Rickard 謆erg ([e-mail])
 * @version $Revision: 1.8 $
 */
public abstract class WebWorkTagSupport
   extends TagSupport
{
   protected ServletValueStack stack;

   // BodyTagSupport overrides --------------------------------------
   public void setPageContext(PageContext aPageContext)
   {
      super.setPageContext(aPageContext);
      stack = null;
   }

   public void setParent(Tag aTag)
   {
      super.setParent(aTag);
      stack = null;
   }

   // Protected -----------------------------------------------------
   protected ServletValueStack getStack()
   {
      if (stack == null)
         stack = ServletValueStack.getStack(pageContext);
      else
      {
      	// Set the pageContext in the stack to make sure that the context
      	// is the correct one, since the same stack is used for the whole
      	// request, which can mean several different pageContexts
         stack.setContext(pageContext);
      }
      return stack;
   }

   protected Object findValue(String aName)
   {
      return getStack().findValue(aName);
   }

   /**
    * Will return the string value of the object. If the object
    * has a ValidationEditor then its getAsText() will be called
    * which by default calls toString() unless you override it.
    */
   protected String findString(String aName)
   {
      String result = null;

      Object value = getStack().findValue(aName);
      if (value!=null) {
         result = BeanUtil.toStringValue(value);
      }
      return result;
   }

   protected String toString(Throwable t)
   {
      ByteArrayOutputStream bout = new ByteArrayOutputStream();
      PrintWriter wrt = new PrintWriter(bout);
      t.printStackTrace(wrt);
      wrt.close();
      return bout.toString();
   }

   public void release()
   {
      stack = null;
   }
}