screenmanager.java.svn-base

一个timesheet程序,用来统计开发人员的度量衡web在线程序.用于软件行业

package com.nsi.control.web;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.nsi.control.web.constants.ScreenFlowConstants;
import com.nsi.control.web.handles.FlowHandler;
import com.nsi.control.web.util.ScreenFlowXml;

/**
 * @author Chris Ye, created on Oct 6, 2008
 *
 * ScreenManager
 */
public class ScreenManager
{
	private static Log log = LogFactory.getLog(ScreenManager.class);
	private String defaultScreen;
	private Map<String,Screen> screens;
	private Map<String, URLMapping> urlMappings;
	/**
	 * constructor of ScreenManager
	 */
	public ScreenManager()
	{
		defaultScreen = ScreenFlowConstants.DEFAULT_SCREEN;
		screens = new HashMap<String,Screen>();
		urlMappings = new HashMap<String,URLMapping>();
	}
	public void init(ServletContext context)
	{
		urlMappings = ScreenFlowXml.getInstance().loadRequestMappings();
		screens = ScreenFlowXml.getInstance().loadScreenDefinitions();
	}
	public void setNextScreen(HttpServletRequest req)
	{
		String selectedUrl = req.getParameter("urlmapping");
		String currentScreen = defaultScreen;
		URLMapping urlMapping = getURLMapping(selectedUrl);
		log.debug("setNextScreen() -- urlMapping[" + urlMapping + "]");
		if(urlMapping != null) if(!urlMapping.isUseFlowHandler())
		{
			currentScreen = urlMapping.getScreen();
		}
		else
		{
			FlowHandler handler = null;
			String flowHandlerString = urlMapping.getFlowHandler();
			try
			{
				handler = (FlowHandler)getClass().getClassLoader().loadClass(flowHandlerString).newInstance();
				String flowResult = handler.processFlow(req);
				currentScreen = urlMapping.getResultScreen(flowResult);
			}
			catch(Exception ex)
			{
				log.error("setNextScreen() -- caught loading handler: ", ex);
			}
		}
		req.getSession().setAttribute("currentScreen", currentScreen);
	}
	public Map<String, Screen> getScreens()
	{
		return screens;
	}
	public void setScreens(Map<String, Screen> screens)
	{
		this.screens = screens;
	}
	public Map<String, URLMapping> getUrlMappings()
	{
		return urlMappings;
	}
	public void setUrlMappings(Map<String, URLMapping> urlMappings)
	{
		this.urlMappings = urlMappings;
	}
	public String getDefaultScreen()
	{
		return defaultScreen;
	}
	public void setDefaultScreen(String defaultScreen)
	{
		this.defaultScreen = defaultScreen;
	}
	public String getCurrentScreen(HttpSession session)
	{
		return (String)session.getAttribute("currentScreen");
	}
	public Parameter getParameter(String key, HttpSession session)
	{
		String currentScreen = getCurrentScreen(session);
		if(currentScreen == null) currentScreen = defaultScreen;
		if(screens == null || currentScreen == null) return null;
		Screen screen = (Screen)screens.get(currentScreen);
		if(screen == null) return null;
		else return screen.getParameter(key);
	}
	public String getTemplate()
	{
		if(screens != null) return "/main.jsp";
		else return null;
	}
	public URLMapping getURLMapping(String urlPattern)
	{
		if(urlMappings != null && urlMappings.containsKey(urlPattern)) return urlMappings.get(urlPattern);
		else return null;
	}
}