// 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 java.util.Iterator;
import org.apache.hivemind.util.Defense;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.TapestryUtils;
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
{
// 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);
StringBuffer buffer = new StringBuffer();
buffer.append(_applicationId);
buffer.append(",");
buffer.append(pageName);
if (idPath != null)
{
buffer.append(",");
buffer.append(idPath);
}
buffer.append(",");
buffer.append(propertyName);
String key = buffer.toString();
session.setAttribute(key, newValue);
}
public Collection getStoredChanges(String pageName, IRequestCycle cycle)
{
Defense.notNull(pageName, "pageName");
WebSession session = _request.getSession(false);
if (session == null)
return Collections.EMPTY_LIST;
Collection result = new ArrayList();
String prefix = _applicationId + "," + pageName + ",";
Iterator i = session.getAttributeNames().iterator();
while (i.hasNext())
{
String key = (String) i.next();
if (key.startsWith(prefix))
{
PropertyChange change = buildChange(key, session.getAttribute(key));
result.add(change);
}
}
return result;
}
private PropertyChange buildChange(String key, Object value)
{
String[] tokens = TapestryUtils.split(key);
// Either app-name,page-name,id-path,property
// or app-name,page-name,property
String idPath = (tokens.length == 4) ? tokens[2] : null;
String propertyName = tokens[tokens.length - 1];
return new PropertyChangeImpl(idPath, propertyName, value);
}
public void discardStoredChanges(String pageName, IRequestCycle cycle)
{
Defense.notNull(pageName, "pageName");
WebSession session = _request.getSession(false);
if (session == null)
return;
String prefix = _applicationId + "," + pageName + ",";
Iterator i = session.getAttributeNames().iterator();
while (i.hasNext())
{
String key = (String) i.next();
if (key.startsWith(prefix))
session.setAttribute(key, null);
}
}
/**
* Does nothing; session persistence does not make use of query parameters.
*/
public void addParametersForPersistentProperties(ServiceEncoding encoding, IRequestCycle cycle)
{
}
public void setApplicationId(String applicationName)
{
_applicationId = applicationName;
}
public void setRequest(WebRequest request)
{
_request = request;
}
}