// Copyright 2007, 2008, 2009, 2010 The Apache Software Foundation
//
// Licensed 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 org.apache.tapestry5.internal.services;
import org.apache.tapestry5.services.ApplicationStateCreator;
import org.apache.tapestry5.services.ApplicationStatePersistenceStrategy;
import org.apache.tapestry5.services.Request;
import org.apache.tapestry5.services.Session;
/**
* Stores ASOs in the {@link Session}, which will be created as necessary.
*/
public class SessionApplicationStatePersistenceStrategy implements ApplicationStatePersistenceStrategy
{
static final String PREFIX = "sso:";
private final Request request;
public SessionApplicationStatePersistenceStrategy(Request request)
{
this.request = request;
}
protected Session getSession()
{
return request.getSession(true);
}
@SuppressWarnings("unchecked")
public <T> T get(Class<T> ssoClass, ApplicationStateCreator<T> creator)
{
return (T) getOrCreate(ssoClass, creator);
}
protected <T> Object getOrCreate(Class<T> ssoClass, ApplicationStateCreator<T> creator)
{
Session session = getSession();
String key = buildKey(ssoClass);
Object sso = session.getAttribute(key);
if (sso == null)
{
sso = creator.create();
set(ssoClass, (T) sso);
}
return sso;
}
protected <T> String buildKey(Class<T> ssoClass)
{
return PREFIX + ssoClass.getName();
}
public <T> void set(Class<T> ssoClass, T sso)
{
String key = buildKey(ssoClass);
getSession().setAttribute(key, sso);
}
public <T> boolean exists(Class<T> ssoClass)
{
String key = buildKey(ssoClass);
Session session = request.getSession(false);
return session != null && session.getAttribute(key) != null;
}
}