package org.nutz.mvc.view;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.http.HttpServletRequest;
import org.nutz.el.El;
import org.nutz.lang.Lang;
import org.nutz.lang.Strings;
import org.nutz.lang.segment.CharSegment;
import org.nutz.lang.segment.Segment;
import org.nutz.lang.util.Context;
import org.nutz.mvc.Loading;
import org.nutz.mvc.Mvcs;
import org.nutz.mvc.View;
import org.nutz.mvc.config.AtMap;
import org.nutz.mvc.impl.processor.ViewProcessor;
/**
* @author mawm(ming300@gmail.com)
* @author wendal(wendal1985@gmail.com)
*/
public abstract class AbstractPathView implements View {
private Segment dest;
private Map<String, El> exps;
public AbstractPathView(String dest) {
if (null != dest) {
this.dest = new CharSegment(Strings.trim(dest));
this.exps = new HashMap<String, El>();
// 预先将每个占位符解析成表达式
for (String key : this.dest.keys()) {
this.exps.put(key, new El(key));
}
}
}
protected String evalPath(HttpServletRequest req, Object obj) {
if (null == dest)
return null;
Context context = Lang.context();
// 解析每个表达式
Context expContext = createContext(req, obj);
for (Entry<String, El> en : exps.entrySet())
context.set(en.getKey(), en.getValue().eval(expContext));
// 生成解析后的路径
return Strings.trim(this.dest.render(context).toString());
}
/**
* 为一次 HTTP 请求，创建一个可以被表达式引擎接受的上下文对象
*
* @param req
* HTTP 请求对象
* @param obj
* 入口函数的返回值
* @return 上下文对象
*/
@SuppressWarnings("unchecked")
public static Context createContext(HttpServletRequest req, Object obj) {
Context context = Lang.context();
// 复制全局的上下文对象
Object globalContext = req.getSession()
.getServletContext()
.getAttribute(Loading.CONTEXT_NAME);
if (globalContext != null) {
context.putAll((Context) globalContext);
}
// 请求对象的属性列表
Map<String,Object> a = new HashMap<String, Object>();
for (Enumeration<String> en = req.getAttributeNames(); en.hasMoreElements();) {
String tem = en.nextElement();
a.put(tem, req.getAttribute(tem));
}
context.set("a", a);//TODO 是否应该用a呢? attr是不是更加好呢?
// 请求的参数表,需要兼容之前的p.参数, Fix issue 418
Map<String,String> p = new HashMap<String, String>();
for (Object o : req.getParameterMap().keySet()) {
String key = (String) o;
String value = req.getParameter(key);
p.put(key, value);
context.set(key, value);//以支持直接获取请求参数
}
context.set("p", p);
//
Map<String, String> u = new HashMap<String, String>();
AtMap at = Mvcs.getAtMap(req.getSession().getServletContext());
if (at != null) {
for(Object o : at.keys()){
String key = (String) o;
u.put(key, at.get(key));
}
context.set("u", u);
}
// 加入返回对象
if (null != obj)
context.set(ViewProcessor.DEFAULT_ATTRIBUTE, obj);
return context;
}
}