iteratetag.java

簡單的多個實例的tag技術,剛入門不久的程序員,多多關照

package com.jspdev.ch14;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.util.*;

public class IterateTag extends BodyTagSupport
{
	/**
	 *Tag的属性
	 */
	private String name;
	//
	private Iterator it;
	//type
	private String type;

	/**
	 *设置属性collection
	 */
	public void setCollection(Collection collection)
	{
		if(collection.size()>0)
		it=collection.iterator();
	}
	public void setName(String name)
	{
		this.name=name;
	}
	public void setType(String type)
	{
		this.type=type;
	}
	/**
	 *如果it属性为null，那么忽略计算tagbody。
	 */
	public int doStartTag()throws JspTagException
	{
		if(it==null)
			return SKIP_BODY;
		else
			return continueNext(it);
	}
	
	public int doAfterBody()throws JspTagException
	{
		return continueNext(it);
	}
	
	public int doEndTag()throws JspTagException
	{
		try
		{
			if(bodyContent!=null)
			bodyContent.writeOut(bodyContent.getEnclosingWriter());
		}
		catch(java.io.IOException e)
		{
		}
		
		return EVAL_PAGE;
	}
	/**
	 *保护方法，用于把it.next()设置为pagecontext的属性
	 */
	protected int continueNext(Iterator it)throws JspTagException
	{
		if(it.hasNext())
		{
			pageContext.setAttribute(name,it.next(),PageContext.PAGE_SCOPE);
			return EVAL_BODY_TAG;
		}
		else
		{
			return SKIP_BODY;
		}
	}
}