optionscollectiontag.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.taglib.html;

import java.lang.reflect.InvocationTargetException;
import java.util.Iterator;

import javax.servlet.jsp.JspException;

import org.apache.commons.beanutils.PropertyUtils;
import org.apache.struts.util.RequestUtils;
import org.apache.struts.util.ResponseUtils;
import org.butor.web.action.IButorActionForm;


/**
 * @author nacroaz 
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 */
public class OptionsCollectionTag
	extends org.apache.struts.taglib.html.OptionsCollectionTag {

    /**
     * Process the start of this tag.
     *
     * @exception JspException if a JSP exception has occurred
     */
    public int doStartTag() throws JspException {

        // Acquire the select tag we are associated with
		SelectTag selectTag = (SelectTag)getParent();

        if (selectTag == null) {
            JspException e = new JspException(
                    messages.getMessage("optionsCollectionTag.select"));
            RequestUtils.saveException(pageContext, e);
            throw e;
        }
        
    	// Find and check the form bean
    	Object o = RequestUtils.lookup(pageContext, name, null);    	
        if (! (o instanceof IButorActionForm)) {
			ResponseUtils.write(pageContext, "The form bean must be an instance of ButorActionForm !!!");  
			return SKIP_BODY;
        }        
        IButorActionForm form = (IButorActionForm) o;
        
        // If selectTag property is enable, then use super class definition        
        if ((form.getEnabled(selectTag.getProperty()))) {        	 
        	return super.doStartTag();
        }
        
        // selectTag property is disable
        // Acquire the collection containing our options
        Object collection = RequestUtils.lookup(pageContext, name, property, null);
        if (collection == null) {
            JspException e = new JspException(
                    messages.getMessage("optionsCollectionTag.collection"));
            RequestUtils.saveException(pageContext, e);
            throw e;
        }

        // Acquire an iterator over the options collection
        Iterator iter = getIterator(collection);

        boolean first = true;

        // Render the selected options
        while (iter.hasNext()) {

            Object bean = iter.next();
            Object beanLabel = null;
            Object beanValue = null;

            // Get the label for this option
            try {
                beanLabel = PropertyUtils.getProperty(bean, label);
                if (beanLabel == null) {
                    beanLabel = "";
                }
            } catch (IllegalAccessException e) {
                JspException jspe = new JspException(
                        messages.getMessage("getter.access", label, bean));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            } catch (InvocationTargetException e) {
                Throwable t = e.getTargetException();
                JspException jspe = new JspException(
                        messages.getMessage("getter.result", label,
                                t.toString()));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            } catch (NoSuchMethodException e) {
                JspException jspe = new JspException(
                        messages.getMessage("getter.method", label, bean));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            }

            // Get the value for this option
            try {
                beanValue = PropertyUtils.getProperty(bean, value);
                if (beanValue == null) {
                    beanValue = "";
                }
            } catch (IllegalAccessException e) {
                JspException jspe = new JspException(
                        messages.getMessage("getter.access", value, bean));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            } catch (InvocationTargetException e) {
                Throwable t = e.getTargetException();
                JspException jspe = new JspException(
                        messages.getMessage("getter.result", value,
                                t.toString()));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            } catch (NoSuchMethodException e) {
                JspException jspe = new JspException(
                        messages.getMessage("getter.method", value, bean));
                RequestUtils.saveException(pageContext, jspe);
                throw jspe;
            }

            String stringLabel = beanLabel.toString();
            String stringValue = beanValue.toString();

            // Render this option
            if (selectTag.isMatched(stringValue)) {
            	// Add this option value
            	if (first) {
            		first = false;	
            	} else {
            		TagLibHelper.renderText(pageContext, "<BR>", false);
            	}       
            	TagLibHelper.renderText(pageContext, stringLabel, true);

				if (!selectTag.getSaveOnDisable().equals("0")) {            	            	     	
	       			// Add an hidden field for this property            	
					TagLibHelper.renderHiddenField(pageContext, selectTag.getProperty(), stringValue);
				}
            }
            
        }

        return SKIP_BODY;        
    }

}