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/*
* File: AbstractRemoteChannel.java
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* The contents of this file are subject to the terms and conditions of
* the Common Development and Distribution License 1.0 (the "License").
*
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the License by consulting the LICENSE.txt file
* distributed with this file, or by consulting https://oss.oracle.com/licenses/CDDL
*
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file LICENSE.txt.
*
* MODIFICATIONS:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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*/
package com.oracle.bedrock.runtime.concurrent;
import com.oracle.bedrock.Option;
import com.oracle.bedrock.OptionsByType;
import com.oracle.bedrock.annotations.Internal;
import com.oracle.bedrock.lang.ThreadFactories;
import com.oracle.bedrock.options.Timeout;
import com.oracle.bedrock.runtime.concurrent.options.Caching;
import com.oracle.bedrock.runtime.concurrent.options.StreamName;
import com.oracle.bedrock.runtime.java.io.ClassLoaderAwareObjectInputStream;
import com.oracle.bedrock.util.Pair;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.NotSerializableException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Modifier;
import java.net.Socket;
import java.time.Instant;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* An abstract implementation of a {@link RemoteChannel}.
*
* Copyright (c) 2013. All Rights Reserved. Oracle Corporation.
* Oracle is a registered trademark of Oracle Corporation and/or its affiliates.
*
* @author Brian Oliver
*/
@Internal
public abstract class AbstractRemoteChannel extends AbstractControllableRemoteChannel
{
/**
* The {@link Logger} for this class.
*/
private static final Logger LOGGER = Logger.getLogger(AbstractRemoteChannel.class.getName());
/**
* The underlying {@link OutputStream} to use for sending requests and raising
* events on the {@link RemoteChannel}.
*/
private final OutputStream underlyingOutput;
/**
* The underlying {@link OutputStream} to use for receiving requests, responses
* and events from the {@link RemoteChannel}.
*/
private final InputStream underlyingInput;
/**
* The {@link ObjectOutputStream} from the {@link RemoteChannel}.
*
* When this is null the {@link RemoteChannel} is not connected.
*/
private ObjectOutputStream output;
/**
* The {@link ObjectInputStream} into the {@link RemoteChannel}.
*
* When this is null the {@link RemoteChannel} is not connected.
*/
private ObjectInputStream input;
/**
* The {@link ExecutorService} for executing tasks asynchronously in sequence
* (a singled threaded worker queue).
*/
private final ExecutorService sequentialExecutionService;
/**
* The {@link ExecutorService} for executing multiple tasks asynchronously and
* concurrently (using multiple worker threads).
*/
private final ExecutorService concurrentExecutionService;
/**
* The {@link Thread} to read {@link Callable}s from the {@link Socket}.
*
* When this is null the {@link AbstractRemoteChannel} is not connected.
*/
private Thread requestAcceptorThread;
/**
* A flag to indicate if the {@link AbstractRemoteChannel} {@link ObjectInputStream}
* is readable.
*/
private final AtomicBoolean isReadable;
/**
* A flag to indicate if the {@link AbstractRemoteChannel} {@link ObjectOutputStream}
* is writable.
*/
private final AtomicBoolean isWritable;
/**
* The defined protocol (of {@link Operation} types) that the
* {@link AbstractRemoteChannel} can process.
*/
@SuppressWarnings("rawtypes")
private final HashMap> protocol;
/**
* The pending {@link Operation}s that are waiting for responses,
* indexed by sequence number.
*/
private final ConcurrentHashMap> pendingOperations;
/**
* The next available sequence number for a callable sent from
* this {@link AbstractRemoteChannel}.
*/
private final AtomicLong nextSequenceNumber;
/**
* The result cache for {@link Callable}s submitted using a {@link Caching#enabled(Option...)}
* option.
*
* The cache is a map from the {@link RemoteCallable} to a {@link Pair}
* consisting of the result and the {@link Instant} when result expires.
*/
private final ConcurrentHashMap, Pair> cache;
/**
* Constructs a {@link AbstractRemoteChannel} to submit and accept {@link Callable}s.
*
* @param outputStream the {@link OutputStream} from the {@link RemoteChannel}
* @param inputStream the {@link InputStream} into the {@link RemoteChannel}
*
* @throws IOException when the {@link RemoteChannel} can't connect provided streams
*/
public AbstractRemoteChannel(OutputStream outputStream,
InputStream inputStream) throws IOException
{
// remember the underlying streams as we may have to interact with them later
this.underlyingOutput = outputStream;
this.underlyingInput = inputStream;
// establish the object output stream
this.output = underlyingOutput instanceof ObjectOutputStream
? (ObjectOutputStream) underlyingOutput : new ObjectOutputStream(underlyingOutput);
// immediately flush to ensure that the object output stream headers are written
// allowing connected streams to begin reading (avoid blocking).
this.output.flush();
this.sequentialExecutionService = Executors.newSingleThreadExecutor(ThreadFactories.usingDaemonThreads(true));
this.concurrentExecutionService = Executors.newCachedThreadPool(ThreadFactories.usingDaemonThreads(true));
this.requestAcceptorThread = null;
this.isReadable = new AtomicBoolean(true);
this.isWritable = new AtomicBoolean(true);
this.protocol = new HashMap<>();
this.pendingOperations = new ConcurrentHashMap<>();
this.nextSequenceNumber = new AtomicLong(0);
// establish the result cache for RemoteCallables
this.cache = new ConcurrentHashMap<>();
// establish the operations that are part of the protocol
protocol.put("CALLABLE", CallableOperation.class);
protocol.put("RESPONSE", ResponseOperation.class);
protocol.put("RUNNABLE", RunnableOperation.class);
protocol.put("EVENT", EventOperation.class);
}
/**
* Get netstats information from OS.
*
* @return the netstat information as an {@link ArrayList}
*/
public ArrayList getNetStatsInfo()
{
ArrayList asPortInfo = new ArrayList<>();
try
{
String sOS = System.getProperty("os.name").toLowerCase();
StringBuilder sbCommand = new StringBuilder().append("netstat ");
if (sOS.contains("mac"))
{
sbCommand.append("-tanp tcp");
}
else if (sOS.contains("linux"))
{
sbCommand.append("-tanpve");
}
else if (sOS.contains("windows"))
{
sbCommand.append("-baonp tcp");
}
Process process = Runtime.getRuntime().exec(sbCommand.toString());
InputStream in = process.getInputStream();
BufferedReader buffer = new BufferedReader(new InputStreamReader(in));
String line;
while ((line = buffer.readLine()) != null)
{
line += System.lineSeparator();
asPortInfo.add(line);
}
return asPortInfo;
}
catch (Exception e)
{
LOGGER.warning(this.getClass().getName() + ".getNetStatsInfo: unexpected Exception: " + e.getLocalizedMessage());
}
return asPortInfo;
}
/**
* Opens the {@link AbstractRemoteChannel} to accept and submit {@link Callable}s.
*/
@SuppressWarnings("rawtypes")
public synchronized void open()
{
if (!isOpen())
{
setOpen(true);
// determine the ClassLoader to use for reading requests
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
// establish the input stream to read requests
try
{
this.input = new ClassLoaderAwareObjectInputStream(classLoader, underlyingInput);
}
catch (IOException e)
{
isReadable.set(false);
setOpen(false);
LOGGER.warning(this.getClass().getName() + ".open: unexpected IOException: " + e.getLocalizedMessage());
LOGGER.info("netstats info: " + getNetStatsInfo());
LOGGER.log(Level.FINE, "stack trace", e);
return;
}
requestAcceptorThread = new Thread(() -> {
while (isReadable.get() && isWritable.get())
{
try
{
// read the operation to perform
String operationType = input.readUTF();
// read the allocated sequence number for the operation
long sequence = input.readLong();
// read the serialized operation from the stream
int length = input.readInt();
byte[] bytes = new byte[length];
input.readFully(bytes, 0, length);
// attempt to instantiate, deserialize and schedule the operation for execution
try
{
ByteArrayInputStream buffer =
new ByteArrayInputStream(bytes);
ObjectInputStream stream =
new ClassLoaderAwareObjectInputStream(classLoader,
buffer);
// instantiate the operation and initialize its state
Class operationClass =
protocol.get(operationType);
Constructor constructor =
operationClass.getConstructor(AbstractRemoteChannel.class);
Operation operation =
constructor.newInstance(AbstractRemoteChannel
.this);
operation.read(stream);
// submit the operation for execution based on the
// operational stream
StreamName streamName = operation.getStreamName();
if (streamName == null)
{
// when there's no stream name, execute the operation concurrently
concurrentExecutionService.submit(new Executor(sequence,
operation));
}
else
{
// when there's stream name, execute the operation sequentially
sequentialExecutionService.submit(new Executor(sequence,
operation));
}
}
catch (Exception e)
{
// when we can't execute the operation we notify the sender of the exception
sequentialExecutionService.submit(new Sender(sequence, new ResponseOperation<>(e)));
}
}
catch (Exception e)
{
// the stream has become corrupted or was closed
// (either way there's nothing else we can read or do)
isReadable.set(false);
LOGGER.log(Level.FINE, "termination of RemoteChannel:RequestAcceptor thread", e);
}
}
close();
});
requestAcceptorThread.setName("RemoteChannel:RequestAcceptor");
requestAcceptorThread.setDaemon(true);
requestAcceptorThread.start();
for (RemoteChannelListener listener : channelListeners)
{
try
{
listener.onOpened(this);
}
catch (Exception e)
{
// we ignore exceptions thrown by listeners
}
}
}
}
@Override
protected void onClose()
{
// no longer accept any more requests
isReadable.set(false);
// gracefully shutdown the executor services
concurrentExecutionService.shutdown();
sequentialExecutionService.shutdown();
// clear all of the event listeners
eventListenersByStreamName.clear();
// no longer write any more responses
isWritable.set(false);
// close the input and output streams
try
{
if (input != null)
{
input.close();
}
}
catch (IOException e)
{
// don't care
}
finally
{
input = null;
}
try
{
if (output != null)
{
output.close();
}
}
catch (IOException e)
{
// don't care
}
finally
{
output = null;
}
// raise IllegalStateExceptions for any remaining pending operations
for (Operation operation : pendingOperations.values())
{
try
{
operation.completeExceptionally(new IllegalStateException("RemoteChannel is closed"));
}
catch (Exception e)
{
// we ignore exceptions that the listener throws
}
}
pendingOperations.clear();
}
@SuppressWarnings({"unchecked", "rawtypes"})
@Override
public CompletableFuture submit(RemoteCallable callable,
Option... options) throws IllegalStateException
{
if (isOpen())
{
OptionsByType optionsByType = OptionsByType.of(options);
// determine if Caching is enabled for this submission
Caching caching = optionsByType.get(Caching.class);
if (caching.isEnabled())
{
// attempt to acquire the existing cache value that hasn't expired
// (if it's expired replace it with null)
Pair pair = cache.compute(callable,
(c, existing) -> existing == null
|| existing.getY()
.isBefore(Instant.now()) ? null : existing);
if (pair != null)
{
CompletableFuture future = new CompletableFuture<>();
future.complete((T) pair.getX());
return future;
}
}
else
{
// ensure the cache is cleared for the current callable
cache.remove(callable);
}
// by default we acknowledge when processed
optionsByType.addIfAbsent(AcknowledgeWhen.PROCESSED);
CallableOperation operation = new CallableOperation<>(callable, optionsByType);
return sendOperation(operation, optionsByType);
}
else
{
throw new IllegalStateException("RemoteChannel is closed");
}
}
@Override
public CompletableFuture submit(RemoteRunnable runnable,
Option... options) throws IllegalStateException
{
if (isOpen())
{
OptionsByType optionsByType = OptionsByType.of(options);
// by default we acknowledge when sent
optionsByType.addIfAbsent(AcknowledgeWhen.SENT);
RunnableOperation operation = new RunnableOperation(runnable, optionsByType);
return sendOperation(operation, optionsByType);
}
else
{
throw new IllegalStateException("RemoteChannel is closed");
}
}
@Override
public CompletableFuture raise(RemoteEvent event,
Option... options)
{
if (isOpen())
{
OptionsByType optionsByType = OptionsByType.of(options);
StreamName streamName = optionsByType.get(StreamName.class);
// by default we acknowledge when sent
optionsByType.addIfAbsent(AcknowledgeWhen.SENT);
EventOperation operation = new EventOperation(streamName, event, optionsByType);
return sendOperation(operation, optionsByType);
}
else
{
throw new IllegalStateException("RemoteChannel is closed");
}
}
private CompletableFuture sendOperation(Operation operation,
OptionsByType optionsByType)
{
long sequence = nextSequenceNumber.getAndIncrement();
Sender sender = new Sender(sequence, operation);
if (optionsByType.get(AcknowledgeWhen.class) == AcknowledgeWhen.SENT)
{
return CompletableFuture.runAsync(sender, sequentialExecutionService).thenApply((_void) -> null);
}
else
{
pendingOperations.put(sequence, operation);
sequentialExecutionService.submit(sender);
return operation.getCompletableFuture();
}
}
/**
* An {@link Operation} to be executed in-order by a {@link AbstractRemoteChannel}.
*
* @param the result returned locally by remotely executing the operation.
*/
interface Operation
{
/**
* Obtains the unique type of {@link Operation}.
*
* @return the type of {@link Operation}
*/
String getType();
/**
* Writes the {@link Operation} state to the specified {@link ObjectOutputStream},
* so that it may later be read from an {@link ObjectInputStream} and executed.
*
* @param output the {@link ObjectOutputStream}
*
* @throws IOException should the write fail
*/
void write(ObjectOutputStream output) throws IOException;
/**
* Reads the {@link Operation} state from the specified {@link ObjectInputStream}.
*
* @param input the {@link ObjectInputStream}
*
* @throws IOException should the read fail
*/
void read(ObjectInputStream input) throws IOException;
/**
* Executes the {@link Operation}.
*
* @param sequence the sequence number of the {@link Operation}
*
* @return Operation the {@link Operation} to be sent back to the initiator of this
* {@link Operation} (if null, nothing is returned)
*/
@SuppressWarnings("rawtypes")
Operation execute(long sequence);
/**
* Obtains the {@link StreamName} on which the {@link Operation} should be processed
* (in sequence) or null when the {@link Operation} has no requirement
* for processing order.
*
* @return the {@link StreamName}
*/
StreamName getStreamName();
/**
* Notifies the {@link Operation} that it was completed with the specified result.
*
* @param result the result
*/
void complete(T result);
/**
* Notifies the {@link Operation} that is was completed exceptionally with the specified {@link Throwable}.
*
* @param throwable the throwable
*/
void completeExceptionally(Throwable throwable);
/**
* Obtains the {@link CompletableFuture} that can be used for acquiring
* the result of the {@link Operation}, including the result and exception thrown.
*
* @return the {@link CompletableFuture}
*/
CompletableFuture getCompletableFuture();
}
/**
* An {@link Operation} to send and execute a {@link Callable}.
*/
@SuppressWarnings({"rawtypes", "unchecked"})
class CallableOperation implements Operation
{
/**
* The {@link CompletableFuture} for the result of the {@link Callable}.
*/
private transient CompletableFuture future;
/**
* The transient {@link OptionsByType} for the {@link Operation}.
*/
private transient OptionsByType optionsByType;
/**
* Is a response required for the {@link Callable}?
*/
private boolean isResponseRequired;
/**
* The {@link Callable} to eventually execute.
*/
private Callable callable;
/**
* Constructs a {@link AbstractRemoteChannel.CallableOperation}
* (required for construction)
*/
@SuppressWarnings("unused")
public CallableOperation()
{
}
/**
* Constructs a {@link AbstractRemoteChannel.CallableOperation}
*
* @param callable the {@link Callable} to execute remotely
* @param optionsByType the {@link OptionsByType} for the execution
*
* @throws NullPointerException should the {@link Callable} be null
* @throws IllegalArgumentException should the {@link Callable} be an anonymous inner class
*/
public CallableOperation(Callable callable,
OptionsByType optionsByType)
{
Class callableClass = callable == null ? null : callable.getClass();
if (callableClass == null)
{
throw new NullPointerException("Callable can't be null");
}
else if (callableClass.isAnonymousClass())
{
throw new IllegalArgumentException("Callable can't be an anonymous inner-class");
}
else if (callableClass.isMemberClass() &&!Modifier.isStatic(callableClass.getModifiers()))
{
throw new IllegalArgumentException("Callable can't be an non-static inner-class");
}
else
{
this.isResponseRequired = optionsByType.get(AcknowledgeWhen.class) == AcknowledgeWhen.PROCESSED;
this.callable = callable;
this.future = new CompletableFuture<>();
this.optionsByType = optionsByType;
}
}
@Override
public String getType()
{
return "CALLABLE";
}
@Override
public Operation execute(long sequence)
{
Operation operation = null;
try
{
// attempt to inject the RemoteChannel into the callable.
AbstractRemoteChannel.this.injectInto(callable);
// execute the Callable
Object result = callable.call();
if (isResponseRequired)
{
operation = new ResponseOperation<>(result);
}
}
catch (Throwable throwable)
{
if (isResponseRequired)
{
operation = new ResponseOperation<>(throwable);
}
}
return operation;
}
@Override
public void read(ObjectInputStream input) throws IOException
{
isResponseRequired = input.readBoolean();
try
{
// read the callable or the name of the callable class
Object object = input.readObject();
if (object instanceof String)
{
String className = (String) object;
Class callableClass = Class.forName(className);
callable = (Callable) callableClass.getDeclaredConstructor().newInstance();
}
else
{
callable = (Callable) object;
}
}
catch (ClassNotFoundException | InstantiationException | IllegalAccessException
| NoSuchMethodException | InvocationTargetException e)
{
throw new IOException(e);
}
}
@Override
public void write(ObjectOutputStream output) throws IOException
{
output.writeBoolean(isResponseRequired);
// serialize the Callable (if it is!)
if (callable instanceof Serializable)
{
output.writeObject(callable);
}
else
{
output.writeObject(callable.getClass().getName());
}
}
@Override
public StreamName getStreamName()
{
return null;
}
@Override
public void complete(T result)
{
// cache the result (if required)
Caching caching = optionsByType.get(Caching.class);
if (caching.isEnabled())
{
// determine the Caching Timeout
Timeout timeout = caching.getOptionsByType().get(Timeout.class);
// determine the Instant in the future when the result will timeout
Instant instant = Instant.now().plusMillis(timeout.to(TimeUnit.MILLISECONDS));
// cache the result for the callable
cache.put(callable, new Pair<>(result, instant));
}
future.complete(result);
}
@Override
public void completeExceptionally(Throwable throwable)
{
future.completeExceptionally(throwable);
}
@Override
public CompletableFuture getCompletableFuture()
{
return future;
}
}
/**
* An {@link Operation} to raise a {@link RemoteEvent}.
*/
@SuppressWarnings("rawtypes")
class EventOperation implements Operation
{
/**
* The {@link CompletableFuture} for notifying of event delivery.
*/
private transient CompletableFuture future;
/**
* The transient {@link OptionsByType} for the {@link Operation}.
*/
private transient OptionsByType optionsByType;
/**
* The {@link StreamName} for the {@link RemoteEvent}
*/
private StreamName streamName;
/**
* The {@link RemoteEvent} to eventually execute.
*/
private RemoteEvent event;
private boolean isAckRequired;
/**
* Constructs an {@link EventOperation}
* (required for serialization)
*/
public EventOperation()
{
}
/**
* Constructs an {@link EventOperation}
*
* @param streamName the {@link StreamName} for the {@link RemoteEvent}
* @param event the {@link RemoteEvent} to fire remotely
*
* @throws NullPointerException should the {@link RemoteEvent} be null
* @throws IllegalArgumentException should the {@link RemoteEvent} be an anonymous inner class
*/
public EventOperation(StreamName streamName,
RemoteEvent event,
OptionsByType optionsByType)
{
if (streamName == null)
{
throw new NullPointerException("The streamName can't be null");
}
else if (event == null)
{
throw new NullPointerException("RemoteEvent can't be null");
}
else if (event.getClass().isAnonymousClass())
{
throw new IllegalArgumentException("RemoteEvent can't be an anonymous inner-class");
}
else
{
this.streamName = streamName;
this.isAckRequired = optionsByType.get(AcknowledgeWhen.class) == AcknowledgeWhen.PROCESSED;
this.event = event;
this.future = new CompletableFuture<>();
this.optionsByType = optionsByType;
}
}
@Override
public String getType()
{
return "EVENT";
}
@Override
public Operation execute(long sequence)
{
Set eventListeners = eventListenersByStreamName.get(streamName);
if (eventListeners != null)
{
eventListeners.forEach(
eventListener -> {
try
{
eventListener.onEvent(event);
}
catch (Throwable e)
{
e.printStackTrace();
}
});
}
return isAckRequired ? new ResponseOperation<>(null) : null;
}
@Override
public void read(ObjectInputStream input) throws IOException
{
try
{
// read the streamName
streamName = StreamName.of(input.readUTF());
// read notification flag
isAckRequired = input.readBoolean();
// read the callable or the name of the callable class
Object object = input.readObject();
if (object instanceof String)
{
String className = (String) object;
event = (RemoteEvent) Class.forName(className).getDeclaredConstructor().newInstance();
}
else
{
event = (RemoteEvent) object;
}
}
catch (ClassNotFoundException | NoSuchMethodException | InvocationTargetException
| InstantiationException | IllegalAccessException e)
{
throw new IOException(e);
}
}
@Override
public void write(ObjectOutputStream output) throws IOException
{
// serialize the stream name
output.writeUTF(streamName.get());
// serialize the notification flag
output.writeBoolean(isAckRequired);
// serialize the Runnable (if it is!)
if (event instanceof Serializable)
{
output.writeObject(event);
}
else
{
output.writeObject(event.getClass().getName());
}
}
@Override
public StreamName getStreamName()
{
return streamName;
}
@Override
public void complete(Void result)
{
future.complete(result);
}
@Override
public void completeExceptionally(Throwable throwable)
{
future.completeExceptionally(throwable);
}
@Override
public CompletableFuture getCompletableFuture()
{
return future;
}
}
/**
* Asynchronously executes an {@link Operation} that was
* received by the {@link AbstractRemoteChannel}.
*/
@SuppressWarnings("rawtypes")
class Executor implements Runnable
{
/**
* The sequence number for the {@link Operation} to execute.
*/
private final long sequence;
/**
* The {@link Operation} to execute.
*/
private final Operation operation;
/**
* Constructs an {@link Executor}.
*
* @param sequence the sequence number of the {@link Operation}
* @param operation the {@link Operation} to execute
*/
public Executor(long sequence,
Operation operation)
{
this.sequence = sequence;
this.operation = operation;
}
@Override
public void run()
{
// execute the operation
Operation resultingOperation = operation.execute(sequence);
// when there's a result, asynchronously send it back
if (resultingOperation != null)
{
sequentialExecutionService.submit(new Sender(sequence, resultingOperation));
}
}
}
/**
* An {@link Operation} to send and deliver a response.
*/
@SuppressWarnings({"rawtypes", "unchecked"})
class ResponseOperation implements Operation
{
/**
* The response.
*/
private T response;
/**
* Constructs a {@link AbstractRemoteChannel.ResponseOperation}
* (required for construction)
*/
public ResponseOperation()
{
}
/**
* Constructs a {@link AbstractRemoteChannel.ResponseOperation}
*
* @param response the response
*/
public ResponseOperation(T response)
{
this.response = response;
}
@Override
public String getType()
{
return "RESPONSE";
}
@Override
public Operation execute(long sequence)
{
Operation operation = pendingOperations.remove(sequence);
if (operation != null)
{
try
{
if (response instanceof Throwable)
{
operation.completeExceptionally((Throwable) response);
}
else
{
operation.complete(response);
}
}
catch (Throwable throwable)
{
// we ignore any exceptions that the future may throw
}
}
return null;
}
@Override
public void read(ObjectInputStream input) throws IOException
{
try
{
response = (T) input.readObject();
}
catch (ClassNotFoundException e)
{
throw new IOException(e);
}
}
@Override
public void write(ObjectOutputStream output) throws IOException
{
output.writeObject(response);
}
@Override
public String toString()
{
return "ResponseOperation{response=" + response + "}";
}
@Override
public StreamName getStreamName()
{
return null;
}
@Override
public void complete(T result)
{
// nothing to do as ResponseOperations never get completed
}
@Override
public void completeExceptionally(Throwable throwable)
{
// nothing to do as ResponseOperations don't throw exceptions
}
@Override
public CompletableFuture getCompletableFuture()
{
return null;
}
}
/**
* An {@link Operation} to send and execute a {@link Runnable}.
*/
@SuppressWarnings("rawtypes")
class RunnableOperation implements Operation
{
/**
* The {@link CompletableFuture} for notifying of {@link Runnable} execution.
*/
private transient CompletableFuture future;
/**
* The {@link Runnable} to eventually execute.
*/
private Runnable runnable;
/**
* Is a response required for the {@link Runnable}?
*/
private boolean isResponseRequired;
/**
* Constructs a {@link RunnableOperation}
* (required for serialization)
*/
public RunnableOperation()
{
}
/**
* Constructs a {@link RunnableOperation}
*
* @param runnable the {@link Runnable} to run remotely
* @param optionsByType the {@link OptionsByType} for the {@link Runnable} execution
*
* @throws NullPointerException should the {@link Runnable} be null
* @throws IllegalArgumentException should the {@link Runnable} be an anonymous inner class
*/
public RunnableOperation(Runnable runnable,
OptionsByType optionsByType)
{
Class runnableClass = runnable == null ? null : runnable.getClass();
if (runnableClass == null)
{
throw new NullPointerException("Runnable can't be null");
}
else if (runnableClass.isAnonymousClass())
{
throw new IllegalArgumentException("Runnable can't be an anonymous inner-class");
}
else if (runnableClass.isMemberClass() &&!Modifier.isStatic(runnableClass.getModifiers()))
{
throw new IllegalArgumentException("Runnable can't be an non-static inner-class");
}
else
{
this.runnable = runnable;
this.isResponseRequired = optionsByType.get(AcknowledgeWhen.class) == AcknowledgeWhen.PROCESSED;
this.future = new CompletableFuture<>();
}
}
@Override
public String getType()
{
return "RUNNABLE";
}
@Override
public Operation execute(long sequence)
{
Operation response = null;
try
{
// attempt to inject the RemoteChannel into the callable.
AbstractRemoteChannel.this.injectInto(runnable);
runnable.run();
if (isResponseRequired)
{
response = new ResponseOperation<>(null);
}
}
catch (Throwable throwable)
{
if (isResponseRequired)
{
response = new ResponseOperation<>(throwable);
}
}
return response;
}
@Override
public void read(ObjectInputStream input) throws IOException
{
isResponseRequired = input.readBoolean();
try
{
// read the callable or the name of the callable class
Object object = input.readObject();
if (object instanceof String)
{
String className = (String) object;
runnable = (Runnable) Class.forName(className).getDeclaredConstructor().newInstance();
}
else
{
runnable = (Runnable) object;
}
}
catch (ClassNotFoundException | InvocationTargetException | NoSuchMethodException
| IllegalAccessException | InstantiationException e)
{
throw new IOException(e);
}
}
@Override
public void write(ObjectOutputStream output) throws IOException
{
output.writeBoolean(isResponseRequired);
// serialize the Runnable (if it is!)
if (runnable instanceof Serializable)
{
output.writeObject(runnable);
}
else
{
output.writeObject(runnable.getClass().getName());
}
}
@Override
public StreamName getStreamName()
{
return null;
}
@Override
public void complete(Void result)
{
future.complete(result);
}
@Override
public void completeExceptionally(Throwable throwable)
{
future.completeExceptionally(throwable);
}
@Override
public CompletableFuture getCompletableFuture()
{
return future;
}
}
/**
* Asynchronously sends an {@link Operation} over the
* {@link ObjectOutputStream} for the {@link AbstractRemoteChannel}.
*/
@SuppressWarnings("rawtypes")
class Sender implements Runnable
{
/**
* The sequence number of the {@link Operation}.
*/
private final long sequence;
/**
* The {@link Operation} to send over the {@link ObjectOutputStream}.
*/
private final Operation operation;
/**
* Constructs an {@link Sender}.
*
* @param sequence the sequence number of the {@link Operation}
* @param operation the {@link Operation}
*/
public Sender(long sequence,
Operation operation)
{
this.sequence = sequence;
this.operation = operation;
}
@Override
public void run()
{
try
{
// create a temporary stream in which to serialize the operation
// (so we can't corrupt the actual output stream if an operation fails to serialize)
ByteArrayOutputStream buffer = new ByteArrayOutputStream(4096); // 4k
ObjectOutputStream stream = new ObjectOutputStream(buffer);
// serialize the operation and send the operation over the stream
// (assume we must send the operation)
boolean sendTemporaryStream;
try
{
// attempt to write the operation to the temporary stream
// (this may fail for numerous reasons,
// but typically because of serialization issues)
operation.write(stream);
// let's send the stream as we successfully serialized the operation!
sendTemporaryStream = true;
}
catch (NotSerializableException e)
{
// determine if the operation required acknowledgement (we can acknowledge failure here)
Operation operation = pendingOperations.remove(sequence);
if (operation == null)
{
// when the operation doesn't require acknowledgment, we assume we must send a response
sendTemporaryStream = true;
// while we failed to serialize the operation, that doesn't mean
// we should fail silently. send the result as an exception to
// let the original caller know.
buffer.reset();
stream = new ObjectOutputStream(buffer);
operation = new ResponseOperation<>(e);
operation.write(stream);
}
else
{
// when there's a "local" future, we assume we don't need to
// send a response to the original caller
sendTemporaryStream = false;
// notify the operation of the exception
operation.completeExceptionally(e);
}
}
if (sendTemporaryStream)
{
// we're done writing (to the buffer)
stream.flush();
// serialize the operation type
// (to the actual output stream)
output.writeUTF(operation.getType());
// serialize the operation sequence number (for responses)
output.writeLong(sequence);
// now send the buffer (to the actual output stream)
byte[] array = buffer.toByteArray();
output.writeInt(array.length);
output.write(array, 0, array.length);
// ensure the buffer is flushed so that the server can read it
output.flush();
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}