package play;
import java.lang.annotation.Annotation;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import com.jamonapi.Monitor;
import com.jamonapi.MonitorFactory;
import java.util.ArrayList;
import play.Play.Mode;
import play.classloading.enhancers.LocalvariablesNamesEnhancer.LocalVariablesNamesTracer;
import play.exceptions.PlayException;
import play.exceptions.UnexpectedException;
import play.i18n.Lang;
import play.libs.F;
import play.libs.F.Promise;
import play.utils.PThreadFactory;
/**
* Run some code in a Play! context
*/
public class Invoker {
/**
* Main executor for requests invocations.
*/
public static ScheduledThreadPoolExecutor executor = null;
/**
* Run the code in a new thread took from a thread pool.
* @param invocation The code to run
* @return The future object, to know when the task is completed
*/
public static Future<?> invoke(final Invocation invocation) {
Monitor monitor = MonitorFactory.getMonitor("Invoker queue size", "elmts.");
monitor.add(executor.getQueue().size());
invocation.waitInQueue = MonitorFactory.start("Waiting for execution");
return executor.submit(invocation);
}
/**
* Run the code in a new thread after a delay
* @param invocation The code to run
* @param millis The time to wait before, in milliseconds
* @return The future object, to know when the task is completed
*/
public static Future<?> invoke(final Invocation invocation, long millis) {
Monitor monitor = MonitorFactory.getMonitor("Invocation queue", "elmts.");
monitor.add(executor.getQueue().size());
return executor.schedule(invocation, millis, TimeUnit.MILLISECONDS);
}
/**
* Run the code in the same thread than caller.
* @param invocation The code to run
*/
public static void invokeInThread(DirectInvocation invocation) {
boolean retry = true;
while (retry) {
invocation.run();
if (invocation.retry == null) {
retry = false;
} else {
try {
if (invocation.retry.task != null) {
invocation.retry.task.get();
} else {
Thread.sleep(invocation.retry.timeout);
}
} catch (Exception e) {
throw new UnexpectedException(e);
}
retry = true;
}
}
}
/**
* The class/method that will be invoked by the current operation
*/
public static class InvocationContext {
public static ThreadLocal<InvocationContext> current = new ThreadLocal<InvocationContext>();
private final List<Annotation> annotations;
private final String invocationType;
public static InvocationContext current() {
return current.get();
}
public InvocationContext(String invocationType) {
this.invocationType = invocationType;
this.annotations = new ArrayList<Annotation>();
}
public InvocationContext(String invocationType, List<Annotation> annotations) {
this.invocationType = invocationType;
this.annotations = annotations;
}
public InvocationContext(String invocationType, Annotation[] annotations) {
this.invocationType = invocationType;
this.annotations = Arrays.asList(annotations);
}
public InvocationContext(String invocationType, Annotation[]... annotations) {
this.invocationType = invocationType;
this.annotations = new ArrayList<Annotation>();
for (Annotation[] some : annotations) {
this.annotations.addAll(Arrays.asList(some));
}
}
public List<Annotation> getAnnotations() {
return annotations;
}
@SuppressWarnings("unchecked")
public <T extends Annotation> T getAnnotation(Class<T> clazz) {
for (Annotation annotation : annotations) {
if (annotation.annotationType().isAssignableFrom(clazz)) {
return (T) annotation;
}
}
return null;
}
public <T extends Annotation> boolean isAnnotationPresent(Class<T> clazz) {
for (Annotation annotation : annotations) {
if (annotation.annotationType().isAssignableFrom(clazz)) {
return true;
}
}
return false;
}
/**
* Returns the InvocationType for this invocation - Ie: A plugin can use this to
* find out if it runs in the context of a background Job
*/
public String getInvocationType() {
return invocationType;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append("InvocationType: ");
builder.append(invocationType);
builder.append(". annotations: ");
for (Annotation annotation : annotations) {
builder.append(annotation.toString()).append(",");
}
return builder.toString();
}
}
/**
* An Invocation in something to run in a Play! context
*/
public static abstract class Invocation implements Runnable {
/**
* If set, monitor the time the invocation waited in the queue
*/
Monitor waitInQueue;
/**
* Override this method
* @throws java.lang.Exception
*/
public abstract void execute() throws Exception;
/**
* Needs this method to do stuff *before* init() is executed.
* The different Invocation-implementations does a lot of stuff in init()
* and they might do it before calling super.init()
*/
protected void preInit() {
// clear language for this request - we're resolving it later when it is needed
Lang.clear();
}
/**
* Init the call (especially usefull in DEV mode to detect changes)
*/
public boolean init() {
Thread.currentThread().setContextClassLoader(Play.classloader);
Play.detectChanges();
if (!Play.started) {
if (Play.mode == Mode.PROD) {
throw new UnexpectedException("Application is not started");
}
Play.start();
}
InvocationContext.current.set(getInvocationContext());
return true;
}
public abstract InvocationContext getInvocationContext();
/**
* Things to do before an Invocation
*/
public void before() {
Thread.currentThread().setContextClassLoader(Play.classloader);
Play.pluginCollection.beforeInvocation();
}
/**
* Things to do after an Invocation.
* (if the Invocation code has not thrown any exception)
*/
public void after() {
Play.pluginCollection.afterInvocation();
LocalVariablesNamesTracer.checkEmpty(); // detect bugs ....
}
/**
* Things to do when the whole invocation has succeeded (before + execute + after)
*/
public void onSuccess() throws Exception {
Play.pluginCollection.onInvocationSuccess();
}
/**
* Things to do if the Invocation code thrown an exception
*/
public void onException(Throwable e) {
Play.pluginCollection.onInvocationException(e);
if (e instanceof PlayException) {
throw (PlayException) e;
}
throw new UnexpectedException(e);
}
/**
* The request is suspended
* @param suspendRequest
*/
public void suspend(Suspend suspendRequest) {
if (suspendRequest.task != null) {
WaitForTasksCompletion.waitFor(suspendRequest.task, this);
} else {
Invoker.invoke(this, suspendRequest.timeout);
}
}
/**
* Things to do in all cases after the invocation.
*/
public void _finally() {
Play.pluginCollection.invocationFinally();
InvocationContext.current.remove();
}
/**
* It's time to execute.
*/
public void run() {
if (waitInQueue != null) {
waitInQueue.stop();
}
try {
preInit();
if (init()) {
before();
execute();
after();
onSuccess();
}
} catch (Suspend e) {
suspend(e);
after();
} catch (Throwable e) {
onException(e);
} finally {
_finally();
}
}
}
/**
* A direct invocation (in the same thread than caller)
*/
public static abstract class DirectInvocation extends Invocation {
public static final String invocationType = "DirectInvocation";
Suspend retry = null;
@Override
public boolean init() {
retry = null;
return super.init();
}
@Override
public void suspend(Suspend suspendRequest) {
retry = suspendRequest;
}
@Override
public InvocationContext getInvocationContext() {
return new InvocationContext(invocationType);
}
}
/**
* Init executor at load time.
*/
static {
int core = Integer.parseInt(Play.configuration.getProperty("play.pool", Play.mode == Mode.DEV ? "1" : ((Runtime.getRuntime().availableProcessors() + 1) + "")));
executor = new ScheduledThreadPoolExecutor(core, new PThreadFactory("play"), new ThreadPoolExecutor.AbortPolicy());
}
/**
* Throwable to indicate that the request must be suspended
*/
public static class Suspend extends PlayException {
/**
* Suspend for a timeout (in milliseconds).
*/
long timeout;
/**
* Wait for task execution.
*/
Future<?> task;
public Suspend(long timeout) {
this.timeout = timeout;
}
public Suspend(Future<?> task) {
this.task = task;
}
@Override
public String getErrorTitle() {
return "Request is suspended";
}
@Override
public String getErrorDescription() {
if (task != null) {
return "Wait for " + task;
}
return "Retry in " + timeout + " ms.";
}
}
/**
* Utility that track tasks completion in order to resume suspended requests.
*/
static class WaitForTasksCompletion extends Thread {
static WaitForTasksCompletion instance;
Map<Future<?>, Invocation> queue;
public WaitForTasksCompletion() {
queue = new ConcurrentHashMap<Future<?>, Invocation>();
setName("WaitForTasksCompletion");
setDaemon(true);
}
public static <V> void waitFor(Future<V> task, final Invocation invocation) {
if (task instanceof Promise) {
Promise<V> smartFuture = (Promise<V>) task;
smartFuture.onRedeem(new F.Action<F.Promise<V>>() {
@Override
public void invoke(Promise<V> result) {
executor.submit(invocation);
}
});
} else {
synchronized (WaitForTasksCompletion.class) {
if (instance == null) {
instance = new WaitForTasksCompletion();
Logger.warn("Start WaitForTasksCompletion");
instance.start();
}
instance.queue.put(task, invocation);
}
}
}
@Override
public void run() {
while (true) {
try {
if (!queue.isEmpty()) {
for (Future<?> task : new HashSet<Future<?>>(queue.keySet())) {
if (task.isDone()) {
executor.submit(queue.get(task));
queue.remove(task);
}
}
}
Thread.sleep(50);
} catch (InterruptedException ex) {
Logger.warn(ex, "While waiting for task completions");
}
}
}
}
}