formfactory.java

CRMS客户关系管理系统(JAVA版）,这是一个客户关系管理系统。

    /* CRMS, customer relationship management system
    Copyright (C) 2003  Service To Youth Council

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    For further information contact the SYC ICT department on [e-mail]
    98 Kermode Street
    North Adelaide
    South Australia
    SA 5006 
    [phone]
    */
/*
 * FormFactory.java
 *
 * Created on 14 April 2003, 03:41
 */

package crms.form;

import java.util.*;
import java.io.*;
import org.w3c.dom.*;
import org.jdom.*;
import org.jdom.output.*;
import org.jdom.input.*;
import org.apache.log4j.Logger;
import java.lang.reflect.*;
import crms.util.*;

/**
 *
 * @author  dmurphy
 */
public class FormFactory {
    
    private static FormFactory _instance = null;
    
    private HashMap formCache = new HashMap();
    private File formDirectory = null;
    
    static Logger logger = Logger.getLogger(FormFactory.class);
    
    /** Creates a new instance of FormFactory */
    private FormFactory() {
    }
    
    public void setFormDirectory(File dir) {
        this.formDirectory = dir;
    }
    
    public static FormFactory getInstance() {
        if (_instance == null) {
            _instance = new FormFactory();
        }
        
        return _instance;
    }
    
    
    public Form createForm(ServerCommand command) {
        
        String formName = (String) command.getParameterValue(ServerCommand.PARAM_FORM_NAME);
        
        Form cached = (Form) formCache.get(formName);
        
        File formFile = new File(formDirectory, formName + ".xml");
        
        if (!formFile.exists()) {
            throw new RuntimeException("Form file: " + formFile + " not found...");
        }

        // If the xml file has changed, grab it and parse it again
        // otherwise return the cached one
        if (cached != null && cached.getDateCreated().getTime() >formFile.lastModified()) {
            logger.debug("Returning cached copy of form...");
            return cached;
        } else {
            logger.debug("Source xml file " + formFile.toString() + " has changed, reparsing...");
        }
        
        Form theForm = null;
        
        try {
        
            SAXBuilder builder = new SAXBuilder(false);
            org.jdom.Document doc = builder.build(formFile);

            DOMOutputter domOut = new DOMOutputter();

            org.w3c.dom.Document newDoc = domOut.output(doc);

            theForm = FormXML.createForm(newDoc.getDocumentElement());
            theForm.setDateCreated(new Date());
            
            // Now that we've got the form object, see if there are any
            // class specifications in any of the fields that we need to
            // expand into options lists.

            processOptionExpansions(theForm);
            
            if (theForm.getPreprocessor() != null) {
                prePopulateForm(theForm, command);
            }
            
            formCache.put(formName, theForm);
        }
        catch (Exception ex) {
            ex.printStackTrace();
            throw new RuntimeException(ex);
        }
        return theForm;
    }
    
    public void processOptionExpansions(Form form) {
        for (int i=0; i < form.getFieldCount(); i++) {
            FormField field = form.getField(i);
            
            if (field.getListClass() != null ) {
                expandOptions(field);
            }
        }
    }
    
    public void expandOptions(FormField field) {
        try {
            Class clazz = Class.forName(field.getListClass());
            
            Object obj = clazz.newInstance();
            
            if (!ListProducer.class.isAssignableFrom(clazz)) {
                throw new RuntimeException("Can only expand options for class which implements ListProducer...");
            }
            
            Method method = clazz.getMethod("produceList",null);
            
            ArrayList list = (ArrayList) method.invoke(obj, null);

            for (int i=0; i < list.size(); i++) {
                AbstractCode code = (AbstractCode) list.get(i);
                field.addOption(new FieldOption(code));
            }
        }
        catch (Exception ex) {
            ex.printStackTrace();
            throw new RuntimeException(ex);
        }
    }
    
    public void prePopulateForm(Form form, ServerCommand command) {

        try {
            Class clazz = Class.forName(form.getPreprocessor());
            
            FormPreProcessor proc = (FormPreProcessor) clazz.newInstance();
            proc.preProcess(form,command);
        }
        catch (Exception ex) {
            ex.printStackTrace();
            throw new RuntimeException(ex);
        }
    }
}