freemarker.ext.servlet.AllHttpScopesHashModel Maven / Gradle / Ivy
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FreeMarker is a "template engine"; a generic tool to generate text output based on templates.
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package freemarker.ext.servlet;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import freemarker.template.ObjectWrapper;
import freemarker.template.SimpleHash;
import freemarker.template.TemplateModel;
import freemarker.template.TemplateModelException;
/**
* An extension of SimpleHash that looks up keys in the hash, then in the
* request, session, and servlet context scopes. Makes "Application", "Session"
* and "Request" keys largely obsolete, however we keep them for backward
* compatibility (also, "Request" is required for proper operation of JSP
* taglibs).
* It is on purpose that we didn't override keys and values
* methods. That way, only those variables assigned into the hash directly by a
* subclass of FreemarkerServlet that overrides
* preTemplateProcess) are discovered as "page" variables by the FM
* JSP PageContext implementation.
*/
public class AllHttpScopesHashModel extends SimpleHash {
private final ServletContext context;
private final HttpServletRequest request;
private final Map unlistedModels = new HashMap();
/**
* Creates a new instance of AllHttpScopesHashModel for handling a single
* HTTP servlet request.
* @param wrapper the object wrapper to use
* @param context the servlet context of the web application
* @param request the HTTP servlet request being processed
*/
public AllHttpScopesHashModel(ObjectWrapper wrapper,
ServletContext context, HttpServletRequest request) {
setObjectWrapper(wrapper);
this.context = context;
this.request = request;
}
/**
* Stores a model in the hash so that it doesn't show up in keys()
* and values() methods. Used to put the Application, Session,
* Request, RequestParameters and JspTaglibs objects.
* @param key the key under which the model is stored
* @param model the stored model
*/
public void putUnlistedModel(String key, TemplateModel model) {
unlistedModels.put(key, model);
}
@Override
public TemplateModel get(String key) throws TemplateModelException {
// Lookup in page scope
TemplateModel model = super.get(key);
if (model != null) {
return model;
}
// Look in unlisted models
model = (TemplateModel) unlistedModels.get(key);
if (model != null) {
return model;
}
// Lookup in request scope
Object obj = request.getAttribute(key);
if (obj != null) {
return wrap(obj);
}
// Lookup in session scope
HttpSession session = request.getSession(false);
if (session != null) {
obj = session.getAttribute(key);
if (obj != null) {
return wrap(obj);
}
}
// Lookup in application scope
obj = context.getAttribute(key);
if (obj != null) {
return wrap(obj);
}
// return wrapper's null object (probably null).
return wrap(null);
}
}
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