actioncontext.java.svn-base

EasyJWeb是基于java技术

package com.easyjf.web;

import java.io.Writer;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

/**
 * 
 * <p>
 * Title:Servlet上下文件处理类
 * </p>
 * <p>
 * Description: 通过使用ThreadLocal变量,实现用户当前访问的Servlet上下文环境访问！<br>
 * 通过使用ActionContext，在用户的Action类可以访问servlet相关资源.如要访问session对象，直接使用ActionContext.getContext().getSession()即可！
 * </p>
 * <p>
 * Copyright: Copyright (c) 2006
 * </p>
 * <p>
 * Company: www.easyjf.com
 * </p>
 * 
 * @author 蔡世友
 * @version 1.0
 */
public class ActionContext {

	public static final String HTTP_REQUEST = "request";

	public static final String HTTP_RESPONSE = "response";

	public static final String HTTP_SESSION = "session";

	public static final String HTTP_PARAMETERS = "parameters";

	public static final String WEBINVOCATION = "WebInvocation";

	public static final String WRITER = "ActionWriter";

	static ThreadLocal actionContext = new ActionContextThreadLocal();

	Map context;

	public ActionContext(Map context) {
		this.context = context;
	}

	/**
	 * 设置当前ActionContext的值
	 * 
	 * @param context
	 *            指定的ActionContext
	 */
	public static void setContext(ActionContext context) {
		actionContext.set(context);
	}

	/**
	 * 返回绑定到当前线程特定的ActionContext.
	 * 
	 * @return 当前线程(当前Request)特定的ActionContext.
	 */
	public static ActionContext getContext() {
		ActionContext context = (ActionContext) actionContext.get();
		if (context == null) {
			context = new ActionContext(new HashMap());
			setContext(context);
		}
		return context;
	}

	public void setContextMap(Map contextMap) {
		getContext().context = contextMap;
	}

	public Map getContextMap() {
		return context;
	}

	/**
	 * 得到HttpServletRequest对象，若在用户的Action中需要直接访问HttpServletRequest，则可以直接通过该访问得到。
	 * 
	 * @return 返回当前HttpServletRequest对象
	 */
	public HttpServletRequest getRequest() {
		HttpServletRequest ret = null;
		if (context.containsKey(HTTP_REQUEST))
			ret = (HttpServletRequest) context.get(HTTP_REQUEST);
		return ret;
	}

	/**
	 * 得到HttpServletResponse对象，若在用户的Action中需要直接访问HttpServletResponse，则可以直接通过该访问得到。
	 * 
	 * @return 返回当前HttpServletResponse对象
	 */
	public HttpServletResponse getResponse() {
		HttpServletResponse ret = null;
		if (context.containsKey(HTTP_RESPONSE))
			ret = (HttpServletResponse) context.get(HTTP_RESPONSE);
		return ret;
	}

	/**
	 * 得到HttpSession对象，若在用户的Action中需要直接访问HttpSession，则可以直接通过该访问得到。
	 * 
	 * @return 返回当前HttpSession对象
	 */
	public HttpSession getSession() {
		HttpSession ret = null;
		if (context.containsKey(HTTP_SESSION))
			ret = (HttpSession) context.get(HTTP_SESSION);
		else {
			HttpServletRequest request = getRequest();
			if (request != null)
				ret = request.getSession();
		}
		return ret;
	}

	/**
	 * 得到当前Request中的参数Map，若在用户的Action中需要直接访问Request中的参数Map，则可以直接通过该方法访问得到。
	 * 
	 * @return 返回当前Request调用中的参数Map即parameterMap
	 */
	public Map getParameters() {
		Map ret = null;
		if (context.containsKey(HTTP_PARAMETERS))
			ret = (Map) context.get(HTTP_PARAMETERS);
		else {
			HttpServletRequest request = getRequest();
			if (request != null)
				ret = request.getParameterMap();
		}
		return ret;
	}

	/**
	 * 得到当前调用中EasyJWeb调用参数信息，包括Module，Form，具体执行的Action等
	 * 
	 * @return 返回EasyJWeb调用参数对象
	 */
	public WebInvocationParam getWebInvocationParam() {
		return (WebInvocationParam) context.get(WEBINVOCATION);
	}

	public Object get(Object key) {
		return context.get(key);
	}

	public Writer getCustomWriter() {
		return (Writer) get(WRITER);
	}

	public String getUri()
	{
		return (String)get("FORWARD");
	}
	/**
	 * 自定义的全局跳转，当在改变默认的writer时，可以通过设置一个全局跳转，让response可以给以响应
	 * @param uri 全局跳转的uri，用于给用户反馈同步信息
	 */
	public void setUri(String uri) {
		this.put("FORWARD", uri);
	}
	public IRequestCallback getRequestCallback()
	{
		return (IRequestCallback)get("RequestCallback");
	}

	public void setRequestCallback(IRequestCallback callback) {
		this.put("RequestCallback", callback);
	}
	/**
	 * 可以手动设置模板的输出，比如下面的代码把EasyJWeb的执行结果输出到文件中：
	 * 
	 * <pre>
	 * java.io.Writer writer = new OutputStreamWriter(new FileOutputStream(new File(
	 * 		&quot;c://test.htm&quot;)), &quot;UTF-8&quot;);
	 * ActionContext.getContext().setCustomWriter(writer);
	 * </pre>
	 * 
	 * @param writer
	 */
	public void setCustomWriter(Writer writer) {
		this.put(WRITER, writer);
	}

	public void put(Object key, Object value) {
		context.put(key, value);
	}

	private static class ActionContextThreadLocal extends ThreadLocal {
		protected synchronized Object initialValue() {
			return new ActionContext(new HashMap());
		}
	}
}