abstractrollovertag.java

java 写的一个新闻发布系统

package org.jahia.taglibs.button;

import org.jahia.data.JahiaData;
import org.jahia.exceptions.JahiaException;
import org.jahia.services.usermanager.JahiaUser;
import org.jahia.taglibs.util.Utils;
import org.jahia.utils.JahiaConsole;

import java.io.*;
import java.util.*;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import javax.servlet.jsp.tagext.*;


/**
 * Class AbstracRolloverTag : defines common code for different rollovers tags
 *
 * @author  Jerome Tamiotti
 */
public abstract class AbstractRolloverTag extends AbstractButtonTag {


    // counter to handle multiple tag occurrences
    private Integer counter;
    
    // the short class name of the tag
    private String className = null;

    // use a counter to identify images in the HTML page
    // in case of several tags
    public void checkCounter(HttpServletRequest request) {
		
        // init class name
		this.className = Utils.getShortClassName(this.getClass());
		// increments the counter or initialize it 
		String counterName = this.className + "_counter";
		this.counter = (Integer)request.getAttribute(counterName);		
		if (this.counter == null) {
		    this.counter = new Integer(1);
		} else {
		    this.counter = new Integer(this.counter.intValue() + 1);
		}
        request.setAttribute(counterName, this.counter);
    }
    

    // build the string drawing the rollover button                
    public String buildButton (JahiaData jData, HttpServletRequest request) {
    
        // get data in subclasses
		String imgDir = getImgDir();
		String width = getWidth();
		String height = getHeight();
		String align = getAlign();
		String imgName = this.className + "Img_";
        String context = jData.gui().drawHttpJspContext(request);
        String outImage = null;
        String overImage = null;
        String launcher = null;
        try {
    		outImage = getMouseOutImage(jData);
	        overImage = getMouseOverImage(jData);
	        launcher = getLauncher(jData);
		} catch (JahiaException jex) {
		    JahiaConsole.println("AbstractRolloverTag: buildButton ", "Can not get launcher from subclass !");
		    return null;
		}
        StringBuffer text = new StringBuffer( "<a href=\"" );
		text.append( launcher );
		text.append( "\" onMouseOut=\"document." );
		text.append( imgName );
		text.append( this.counter );
		text.append( ".src='" );
		text.append( context );
		text.append( "/" );
		text.append( imgDir );
		text.append( "/" );
		text.append( outImage );
		text.append( "';\" onMouseOver=\"document." );
		text.append( imgName );
		text.append( this.counter );
		text.append( ".src='" );
		text.append( context );
		text.append( "/" );
		text.append( imgDir );
		text.append( "/" );
		text.append( overImage );
		text.append( "';\"><img name=\"" );
		text.append( imgName );
        text.append( this.counter.intValue() );
        text.append( "\" src=\"" );
		text.append( context );
		text.append( "/" );
		text.append( imgDir );
		text.append( "/" );
	    text.append( outImage );
	    text.append( "\"" );
	    if ( !width.equals("" ) ) {
            text.append( " width=\"" );
            text.append( width );
		    text.append( "\"" );
		}
        if ( !height.equals("") ) {
            text.append( " height=\"" );
            text.append( height );
		    text.append( "\"" );
		}
        if ( !align.equals("") ) {
            text.append( " align=\"" );
            text.append( align );
		    text.append( "\"" );
		}

		text.append( " border=\"0\" alt=\"\">" );
		text.append( getTitle() );
		text.append( "</a>" );
		return text.toString();       
    }

    public String getTitle() {
        return "";
    }

    public String getStyle() {
        return "";
    }

    public String getAlign(){
    	return "";	
    };    

	// The following methods will be implemented in the concrete rollover tags
    public abstract String getMouseOverImage(JahiaData jData) throws JahiaException;
    
    public abstract String getMouseOutImage(JahiaData jData) throws JahiaException;

    public abstract String getImgDir();
    
    public abstract String getWidth();
    
    public abstract String getHeight();    
    
}