// Copyright 2007 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.internal.services;
import static org.apache.tapestry.ioc.internal.util.CollectionFactory.newConcurrentMap;
import java.util.Map;
import org.apache.tapestry.services.ApplicationStateContribution;
import org.apache.tapestry.services.ApplicationStateCreator;
import org.apache.tapestry.services.ApplicationStateManager;
import org.apache.tapestry.services.ApplicationStatePersistenceStrategy;
import org.apache.tapestry.services.ApplicationStatePersistenceStrategySource;
public class ApplicationStateManagerImpl implements ApplicationStateManager
{
static final String DEFAULT_STRATEGY = "session";
static class ApplicationStateAdapter<T>
{
private final Class<T> _asoClass;
private final ApplicationStatePersistenceStrategy _strategy;
private final ApplicationStateCreator<T> _creator;
ApplicationStateAdapter(Class<T> asoClass, ApplicationStatePersistenceStrategy strategy,
ApplicationStateCreator<T> creator)
{
_asoClass = asoClass;
_strategy = strategy;
_creator = creator;
}
T getOrCreate()
{
return _strategy.get(_asoClass, _creator);
}
void set(T aso)
{
_strategy.set(_asoClass, aso);
}
};
/**
* The map will be extended periodically as new ASOs, not in the configuration, are encountered.
* Thus is is thread safe.
*/
private final Map<Class, ApplicationStateAdapter> _classToAdapter;
private final ApplicationStatePersistenceStrategySource _source;
@SuppressWarnings("unchecked")
public ApplicationStateManagerImpl(Map<Class, ApplicationStateContribution> configuration,
ApplicationStatePersistenceStrategySource source)
{
_classToAdapter = newConcurrentMap();
_source = source;
for (Class asoClass : configuration.keySet())
{
ApplicationStateContribution contribution = configuration.get(asoClass);
ApplicationStateAdapter adapter = newAdapter(
asoClass,
contribution.getStrategy(),
contribution.getCreator());
_classToAdapter.put(asoClass, adapter);
}
}
@SuppressWarnings("unchecked")
private <T> ApplicationStateAdapter<T> newAdapter(final Class<T> asoClass, String strategyName,
ApplicationStateCreator<T> creator)
{
if (creator == null)
creator = new ApplicationStateCreator<T>()
{
public T create()
{
try
{
return asoClass.newInstance();
}
catch (Exception ex)
{
throw new RuntimeException(ex);
}
}
};
ApplicationStatePersistenceStrategy strategy = _source.get(strategyName);
return new ApplicationStateAdapter(asoClass, strategy, creator);
}
@SuppressWarnings("unchecked")
private <T> ApplicationStateAdapter<T> getAdapter(Class<T> asoClass)
{
ApplicationStateAdapter<T> result = _classToAdapter.get(asoClass);
// Not found is completely OK, we'll define it on the fly.
if (result == null)
{
result = newAdapter(asoClass, DEFAULT_STRATEGY, null);
_classToAdapter.put(asoClass, result);
}
return result;
}
public <T> T get(Class<T> asoClass)
{
return getAdapter(asoClass).getOrCreate();
}
public <T> void set(Class<T> asoClass, T aso)
{
getAdapter(asoClass).set(aso);
}
}