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/**
*
* Copyright 2005 The Apache Software Foundation or its licensors, as applicable.
*
* 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.tuscany.core.context.scope;
import java.util.Map;
import java.util.Queue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import org.apache.tuscany.core.builder.RuntimeConfiguration;
import org.apache.tuscany.core.context.InstanceContext;
import org.apache.tuscany.core.context.Context;
import org.apache.tuscany.core.context.LifecycleEventListener;
import org.apache.tuscany.core.context.CoreRuntimeException;
import org.apache.tuscany.core.context.EventContext;
import org.apache.tuscany.core.context.RuntimeEventListener;
import org.apache.tuscany.core.context.SimpleComponentContext;
/**
* An implementation of a request-scoped component container.
*
* @version $Rev$ $Date$
*/
public class RequestScopeContext extends AbstractScopeContext implements RuntimeEventListener, LifecycleEventListener {
// ----------------------------------
// Fields
// ----------------------------------
// A collection of service component contexts keyed by thread. Note this could have been implemented with a ThreadLocal but
// using a Map allows finer-grained concurrency.
private Map<Object, Map<String, InstanceContext>> contextMap;
// stores ordered lists of contexts to shutdown for each thread.
private Map<Object, Queue> destroyComponents;
// ----------------------------------
// Constructor
// ----------------------------------
public RequestScopeContext(EventContext eventContext) {
super(eventContext);
setName("Request Scope");
}
// ----------------------------------
// Listener methods
// ----------------------------------
public void onEvent(int type, Object key) {
checkInit();
/* clean up current context for pooled threads */
if (type == EventContext.REQUEST_END) {
getEventContext().clearIdentifier(EventContext.HTTP_SESSION);
notifyInstanceShutdown(Thread.currentThread());
destroyContext();
}
}
// ----------------------------------
// Lifecycle methods
// ----------------------------------
public synchronized void start() {
if (lifecycleState != UNINITIALIZED) {
throw new IllegalStateException("Scope must be in UNINITIALIZED state [" + lifecycleState + "]");
}
super.start();
contextMap = new ConcurrentHashMap();
destroyComponents = new ConcurrentHashMap();
lifecycleState = RUNNING;
}
public synchronized void stop() {
if (lifecycleState != RUNNING) {
throw new IllegalStateException("Scope in wrong state [" + lifecycleState + "]");
}
super.stop();
contextMap = null;
destroyComponents = null;
lifecycleState = STOPPED;
}
// ----------------------------------
// Methods
// ----------------------------------
public boolean isCacheable() {
return true;
}
public void registerConfiguration(RuntimeConfiguration<InstanceContext> configuration) {
runtimeConfigurations.put(configuration.getName(), configuration);
}
public InstanceContext getContext(String ctxName) {
checkInit();
Map<String, InstanceContext> contexts = getComponentContexts();
InstanceContext ctx = contexts.get(ctxName);
if (ctx == null){
// check to see if the configuration was added after the request was started
RuntimeConfiguration<InstanceContext> configuration = runtimeConfigurations.get(ctxName);
if (configuration != null) {
ctx = configuration.createInstanceContext();
ctx.addContextListener(this);
ctx.start();
contexts.put(ctx.getName(), ctx);
}
}
return ctx;
}
public InstanceContext getContextByKey(String ctxName, Object key) {
checkInit();
if (key == null) {
return null;
}
Map<String, InstanceContext> components = (Map) contextMap.get(key);
if (components == null) {
return null;
}
return components.get(ctxName);
}
public void removeContext(String ctxName) {
checkInit();
removeContextByKey(ctxName, Thread.currentThread());
}
public void removeContextByKey(String ctxName, Object key) {
checkInit();
if (key == null || ctxName == null) {
return;
}
Map components = (Map) contextMap.get(key);
if (components == null) {
return;
}
components.remove(ctxName);
Map<String, InstanceContext> contexts = (Map) contextMap.get(key);
// no synchronization for the following two operations since the request
// context will not be shutdown before the second call is processed
InstanceContext context = contexts.get(ctxName);
destroyComponents.get(key).remove(context);
}
public void onInstanceCreate(Context context) {
checkInit();
if (context instanceof SimpleComponentContext) {
// Queue the context to have its implementation instance released if destroyable
if (((SimpleComponentContext) context).isDestroyable()) {
Queue collection = destroyComponents.get(Thread.currentThread());
collection.add(context);
}
}
}
/**
* Returns an array of {@link SimpleComponentContext}s representing components that need to be notified of scope shutdown.
*/
protected InstanceContext[] getShutdownContexts(Object key) {
checkInit();
Queue queue = destroyComponents.get(Thread.currentThread());
if (queue != null) {
// create 0-length array since Queue.size() has O(n) traversal
return (InstanceContext[]) queue.toArray(new InstanceContext[0]);
} else {
return null;
}
}
// ----------------------------------
// Private methods
// ----------------------------------
private void destroyContext() {
// TODO uninitialize all request-scoped components
contextMap.remove(Thread.currentThread());
destroyComponents.remove(Thread.currentThread());
}
/**
* Initializes ServiceComponentContexts for the current request.
* <p>
* TODO This eagerly creates all component contexts, even if the component is never accessed during the request. This method
* should be profiled to determine if lazy initialization is more performant
* <p>
* TODO Eager initialization is not performed for request-scoped components
*/
private Map<String, InstanceContext> getComponentContexts() throws CoreRuntimeException {
Map contexts = (Map) contextMap.get(Thread.currentThread());
if (contexts == null) {
contexts = new ConcurrentHashMap();
Queue shutdownQueue = new ConcurrentLinkedQueue();
for (RuntimeConfiguration<InstanceContext> config : runtimeConfigurations.values()) {
InstanceContext context = null;
context = config.createInstanceContext();
context.addContextListener(this);
context.start();
contexts.put(context.getName(), context);
}
contextMap.put(Thread.currentThread(), contexts);
destroyComponents.put(Thread.currentThread(), shutdownQueue);
}
return contexts;
}
}
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