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Central module for Tapestry, containing interfaces to the Java
Servlet API and all core services and components.
// Copyright 2006, 2007, 2008 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.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.ioc.internal.util.OneShotLock;
import org.apache.tapestry5.ioc.services.ThreadCleanupListener;
import org.apache.tapestry5.services.Environment;
import org.apache.tapestry5.services.EnvironmentalAccess;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* A non-threadsafe implementation (expects to use the "perthread" service lifecyle).
*/
public class EnvironmentImpl implements Environment, ThreadCleanupListener
{
// My generics mojo breaks down when we talk about the key and the value being related
// types.
private final Map typeToStack = CollectionFactory.newMap();
private final Map typeToAccess = CollectionFactory.newMap();
private final OneShotLock lock = new OneShotLock();
@SuppressWarnings("unchecked")
private LinkedList stackFor(Class type)
{
lock.check();
LinkedList result = typeToStack.get(type);
if (result == null)
{
result = CollectionFactory.newLinkedList();
typeToStack.put(type, result);
}
return result;
}
public T peek(Class type)
{
LinkedList stack = stackFor(type);
return stack.isEmpty() ? null : stack.getFirst();
}
public T peekRequired(Class type)
{
T result = peek(type);
if (result == null)
{
List types = CollectionFactory.newList();
for (Map.Entry e : typeToStack.entrySet())
{
LinkedList list = e.getValue();
if (list != null && !list.isEmpty()) types.add(e.getKey());
}
throw new RuntimeException(ServicesMessages.missingFromEnvironment(type, types));
}
return result;
}
public T pop(Class type)
{
LinkedList stack = stackFor(type);
invalidate(type);
return stack.removeFirst();
}
public T push(Class type, T instance)
{
LinkedList stack = stackFor(type);
T result = stack.isEmpty() ? null : stack.getFirst();
stack.addFirst(instance);
invalidate(type);
return result;
}
public void clear()
{
lock.check();
typeToStack.clear();
for (EnvironmentalAccessImpl closure : typeToAccess.values())
{
closure.invalidate();
}
}
public EnvironmentalAccess getAccess(Class type)
{
lock.check();
EnvironmentalAccessImpl access = typeToAccess.get(type);
if (access == null)
{
access = new EnvironmentalAccessImpl(this, type);
typeToAccess.put(type, access);
}
return access;
}
public void threadDidCleanup()
{
lock.lock();
}
void invalidate(Class type)
{
EnvironmentalAccessImpl access = typeToAccess.get(type);
if (access != null) access.invalidate();
}
}