iteratetag.java

《J2EE企业级应用开发》一书的配套源代码

package com.j2eeapp.ch18;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;
import java.util.*;

public class IterateTag extends BodyTagSupport
{
	private String name;
	private Iterator iterator;
	private String type;
	
	public IterateTag()
	{
		super();
	}
	public void setCollection(Collection collection)
	{
		if(collection.size()>0)
         iterator=collection.iterator();
	}
	
	public void setName(String name)
	{
		this.name=name;
	}
	public void setType(String type)
	{
		this.type=type;
	}

	public int doStartTag()throws JspTagException
	{
		if(iterator==null)
			{
				return SKIP_BODY;
			}
		return addNext(iterator);
	}

	public int doAfterBody()throws JspTagException
	{
		return addNext(iterator);
	}

	public int doEndTag()throws JspTagException
	{
		try
		{
			if(bodyContent!=null)
			bodyContent.writeOut(bodyContent.getEnclosingWriter());
		}
		catch(java.io.IOException e)
		{
			throw new JspTagException(e.getMessage());
		}
		return EVAL_PAGE;
	}

	protected int addNext(Iterator iterator)throws JspTagException
	{
		if(iterator.hasNext())
		{
			pageContext.setAttribute(name,iterator.next(),PageContext.PAGE_SCOPE);
			return EVAL_BODY_TAG;
		}
		else
		{
			return SKIP_BODY;
		}
	}
}