// Copyright 2005 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.tapestry.record;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import org.apache.hivemind.util.Defense;
import org.apache.tapestry.engine.ServiceEncoding;
import org.apache.tapestry.web.WebRequest;
import org.apache.tapestry.web.WebSession;
/**
* The most basic {@link org.apache.tapestry.record.PropertyPersistenceStrategy},
* which stores properties in the HttpSession as attributes.
*
* @author Howard M. Lewis Ship
* @since 4.0
*/
public class SessionPropertyPersistenceStrategy implements
PropertyPersistenceStrategy
{
public static final String STRATEGY_ID = "session";
// Really, the name of the servlet; used as a prefix on all
// HttpSessionAttribute keys
// to keep things straight if multiple Tapestry apps are deployed
// in the same WAR.
private String _applicationId;
private WebRequest _request;
public void store(String pageName, String idPath, String propertyName,
Object newValue)
{
Defense.notNull(pageName, "pageName");
Defense.notNull(propertyName, "propertyName");
WebSession session = _request.getSession(true);
String attributeName = RecordUtils.buildChangeKey(STRATEGY_ID,
_applicationId, pageName, idPath, propertyName);
session.setAttribute(attributeName, newValue);
}
public Collection getStoredChanges(String pageName)
{
Defense.notNull(pageName, "pageName");
WebSession session = _request.getSession(false);
if (session == null) return Collections.EMPTY_LIST;
final Collection result = new ArrayList();
WebSessionAttributeCallback callback = new WebSessionAttributeCallback()
{
public void handleAttribute(WebSession sess, String name)
{
PropertyChange change = RecordUtils.buildChange(name, sess
.getAttribute(name));
result.add(change);
}
};
RecordUtils.iterateOverMatchingAttributes(STRATEGY_ID, _applicationId,
pageName, session, callback);
return result;
}
public void discardStoredChanges(String pageName)
{
WebSession session = _request.getSession(false);
if (session == null) return;
WebSessionAttributeCallback callback = new WebSessionAttributeCallback()
{
public void handleAttribute(WebSession sess, String name)
{
sess.setAttribute(name, null);
}
};
RecordUtils.iterateOverMatchingAttributes(STRATEGY_ID, _applicationId,
pageName, session, callback);
}
/**
* Does nothing; session persistence does not make use of query parameters.
*/
public void addParametersForPersistentProperties(ServiceEncoding encoding,
boolean post)
{
}
public void setApplicationId(String applicationName)
{
_applicationId = applicationName;
}
public void setRequest(WebRequest request)
{
_request = request;
}
}