GetTag.java

package com.ziqewgww.tag;

import java.util.Hashtable;
import java.util.Stack;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.TagSupport;

public class GetTag extends TagSupport {
	   private String name;
	   // setter method for name attribute
	   public void setName(String name) {
	      this.name = name;
	   }
	   public int doStartTag() throws JspException {
	      // obtain reference to template stack
	      Stack stack = (Stack)pageContext.getAttribute(
	               "template-stack", PageContext.REQUEST_SCOPE);
	      // stack should not be null
	      if(stack == null)
	         throw new JspException("GetTag.doStartTag(): " +
	                                 "NO STACK");
	      // peek at hashtable
	      Hashtable params = (Hashtable)stack.peek();
	      // hashtable should not be null
	      if(params == null)
	         throw new JspException("GetTag.doStartTag(): " +
	                                 "NO HASHTABLE");
	      // get page parameter from hashtable
	      PageParameter param = (PageParameter)params.get(name);
	      if(param != null) {
	         String content = param.getContent();
	         if(param.isDirect()) {
	            // print content if direct attribute is true
	            try {
	               pageContext.getOut().print(content);
	            }
	            catch(java.io.IOException ex) {
	               throw new JspException(ex.getMessage());
	            }
	         }
	         else {
	            // include content if direct attribute is false
	            try {
	               pageContext.getOut().flush();
	               pageContext.include(content);
	            }
	            catch(Exception ex) {
	               throw new JspException(ex.getMessage());
	            }
	         }
	      }
	      return SKIP_BODY; // not interested in tag body, if present
	   }
	   // tag handlers should always implement release() because
	   // handlers can be reused by the JSP container
	   public void release() {
	      name = null;
	   }
	}