pagefieldabstract.java

java 写的一个新闻发布系统

package org.jahia.taglibs.field.page;

import org.jahia.exceptions.JahiaException;
import org.jahia.services.pages.JahiaPage;
import org.jahia.utils.JahiaConsole;

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

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


/**
 * Class PageFieldAbstract : abstract class for the PageField tag
 *
 *     This class will be extended by all the classes which want to display
 *     a JahiaPageField attribute. It retrieves the current JahiaPageField
 *     and call a method which returns an attribute of this object.
 *     This attribute is defined in each subclass.
 *
 * @author  Jerome Tamiotti
 */
public abstract class PageFieldAbstract extends TagSupport {

    protected JahiaPage thePage = null;

    public int doStartTag() throws JspTagException {

        ServletRequest request = pageContext.getRequest();
        // retrieves the enclosing PageField tag
        PageFieldTag pageTag = (PageFieldTag) findAncestorWithClass(this, PageFieldTag.class);
        if (pageTag == null) {
            return SKIP_BODY;
        }
        // reads the page
        thePage = pageTag.getPage();
        if (thePage == null) {
            return SKIP_BODY;
        }
        try {
            JspWriter out = pageContext.getOut();
            out.print(getField());
        } catch (IOException ioe) {
            JahiaConsole.println("PageFieldAbstract: doStartTag ",ioe.toString());
        }
        return SKIP_BODY;
    }

    // will be implemented in the classes mentionned above
    public abstract String getField();

}