You are viewing a plain text version of this content. The canonical link for it is here.
Posted to jira@kafka.apache.org by GitBox <gi...@apache.org> on 2021/07/02 00:35:09 UTC
[GitHub] [kafka] kkonstantine commented on a change in pull request #9878: KAFKA-6987: Add KafkaFuture.toCompletionStage()
kkonstantine commented on a change in pull request #9878:
URL: https://github.com/apache/kafka/pull/9878#discussion_r662652853
##########
File path: clients/src/main/java/org/apache/kafka/common/internals/KafkaFutureImpl.java
##########
@@ -27,217 +28,107 @@
/**
* A flexible future which supports call chaining and other asynchronous programming patterns.
- * This will eventually become a thin shim on top of Java 8's CompletableFuture.
*/
public class KafkaFutureImpl<T> extends KafkaFuture<T> {
- /**
- * A convenience method that throws the current exception, wrapping it if needed.
- *
- * In general, KafkaFuture throws CancellationException and InterruptedException directly, and
- * wraps all other exceptions in an ExecutionException.
- */
- private static void wrapAndThrow(Throwable t) throws InterruptedException, ExecutionException {
- if (t instanceof CancellationException) {
- throw (CancellationException) t;
- } else if (t instanceof InterruptedException) {
- throw (InterruptedException) t;
- } else {
- throw new ExecutionException(t);
- }
- }
- private static class Applicant<A, B> implements BiConsumer<A, Throwable> {
- private final BaseFunction<A, B> function;
- private final KafkaFutureImpl<B> future;
+ private final KafkaCompletableFuture<T> completableFuture;
- Applicant(BaseFunction<A, B> function, KafkaFutureImpl<B> future) {
- this.function = function;
- this.future = future;
- }
+ private final boolean isDependant;
- @Override
- public void accept(A a, Throwable exception) {
- if (exception != null) {
- future.completeExceptionally(exception);
- } else {
- try {
- B b = function.apply(a);
- future.complete(b);
- } catch (Throwable t) {
- future.completeExceptionally(t);
- }
- }
- }
+ public KafkaFutureImpl() {
+ this(false, new KafkaCompletableFuture<>());
}
- private static class SingleWaiter<R> implements BiConsumer<R, Throwable> {
- private R value = null;
- private Throwable exception = null;
- private boolean done = false;
-
- @Override
- public synchronized void accept(R newValue, Throwable newException) {
- this.value = newValue;
- this.exception = newException;
- this.done = true;
- this.notifyAll();
- }
-
- synchronized R await() throws InterruptedException, ExecutionException {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- this.wait();
- }
- }
-
- R await(long timeout, TimeUnit unit)
- throws InterruptedException, ExecutionException, TimeoutException {
- long startMs = System.currentTimeMillis();
- long waitTimeMs = unit.toMillis(timeout);
- long delta = 0;
- synchronized (this) {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- if (delta >= waitTimeMs) {
- throw new TimeoutException();
- }
- this.wait(waitTimeMs - delta);
- delta = System.currentTimeMillis() - startMs;
- }
- }
- }
+ public KafkaFutureImpl(KafkaCompletableFuture<T> completableFuture) {
+ this(false, completableFuture);
}
- /**
- * True if this future is done.
- */
- private boolean done = false;
-
- /**
- * The value of this future, or null. Protected by the object monitor.
- */
- private T value = null;
-
- /**
- * The exception associated with this future, or null. Protected by the object monitor.
- */
- private Throwable exception = null;
+ private KafkaFutureImpl(boolean isDependant, KafkaCompletableFuture<T> completableFuture) {
+ this.isDependant = isDependant;
+ this.completableFuture = completableFuture;
+ }
- /**
- * A list of objects waiting for this future to complete (either successfully or
- * exceptionally). Protected by the object monitor.
- */
- private List<BiConsumer<? super T, ? super Throwable>> waiters = new ArrayList<>();
+ @Override
+ public CompletionStage<T> toCompletionStage() {
+ return completableFuture;
+ }
/**
* Returns a new KafkaFuture that, when this future completes normally, is executed with this
* futures's result as the argument to the supplied function.
*/
@Override
public <R> KafkaFuture<R> thenApply(BaseFunction<T, R> function) {
- KafkaFutureImpl<R> future = new KafkaFutureImpl<>();
- addWaiter(new Applicant<>(function, future));
- return future;
+ CompletableFuture<R> completableFuture = this.completableFuture.thenApply((java.util.function.Function<? super T, ? extends R>) value -> {
+ try {
+ return function.apply(value);
+ } catch (Throwable t) {
+ if (t instanceof CompletionException) {
+ throw new CompletionException(t);
+ } else {
+ throw t;
+ }
+ }
+ });
+ return new KafkaFutureImpl<>(true, toKafkaCompletableFuture(completableFuture));
}
- public <R> void copyWith(KafkaFuture<R> future, BaseFunction<R, T> function) {
- KafkaFutureImpl<R> futureImpl = (KafkaFutureImpl<R>) future;
- futureImpl.addWaiter(new Applicant<>(function, this));
+ private <U> KafkaCompletableFuture<U> toKafkaCompletableFuture(CompletableFuture<U> tCompletableFuture) {
+ KafkaCompletableFuture<U> res;
+ if (tCompletableFuture instanceof KafkaCompletableFuture) {
+ res = (KafkaCompletableFuture<U>) tCompletableFuture;
+ } else {
+ KafkaCompletableFuture<U> result = new KafkaCompletableFuture<>();
+ tCompletableFuture.whenComplete((x, y) -> {
+ if (y != null) {
+ result.kafkaCompleteExceptionally(y);
+ } else {
+ result.kafkaComplete(x);
+ }
+ });
+ res = result;
+ }
+ return res;
}
/**
* @see KafkaFutureImpl#thenApply(BaseFunction)
+ * @deprecated Since Kafka 3.0.
*/
+ @Deprecated
@Override
public <R> KafkaFuture<R> thenApply(Function<T, R> function) {
return thenApply((BaseFunction<T, R>) function);
}
- private static class WhenCompleteBiConsumer<T> implements BiConsumer<T, Throwable> {
- private final KafkaFutureImpl<T> future;
- private final BiConsumer<? super T, ? super Throwable> biConsumer;
-
- WhenCompleteBiConsumer(KafkaFutureImpl<T> future, BiConsumer<? super T, ? super Throwable> biConsumer) {
- this.future = future;
- this.biConsumer = biConsumer;
- }
-
- @Override
- public void accept(T val, Throwable exception) {
+ @Override
+ public KafkaFuture<T> whenComplete(final BiConsumer<? super T, ? super Throwable> biConsumer) {
+ CompletableFuture<T> tCompletableFuture = completableFuture.whenComplete((java.util.function.BiConsumer<? super T, ? super Throwable>) (a, b) -> {
try {
- if (exception != null) {
- biConsumer.accept(null, exception);
+ biConsumer.accept(a, b);
+ } catch (Throwable t) {
+ if (t instanceof CompletionException) {
+ throw new CompletionException(t);
} else {
- biConsumer.accept(val, null);
+ throw t;
}
- } catch (Throwable e) {
- if (exception == null) {
- exception = e;
- }
- }
- if (exception != null) {
- future.completeExceptionally(exception);
- } else {
- future.complete(val);
}
- }
+ });
+ return new KafkaFutureImpl<>(true, toKafkaCompletableFuture(tCompletableFuture));
}
- @Override
- public KafkaFuture<T> whenComplete(final BiConsumer<? super T, ? super Throwable> biConsumer) {
- final KafkaFutureImpl<T> future = new KafkaFutureImpl<>();
- addWaiter(new WhenCompleteBiConsumer<>(future, biConsumer));
- return future;
- }
-
- protected synchronized void addWaiter(BiConsumer<? super T, ? super Throwable> action) {
- if (exception != null) {
- action.accept(null, exception);
- } else if (done) {
- action.accept(value, null);
- } else {
- waiters.add(action);
- }
- }
@Override
public synchronized boolean complete(T newValue) {
- List<BiConsumer<? super T, ? super Throwable>> oldWaiters;
- synchronized (this) {
- if (done)
- return false;
- value = newValue;
- done = true;
- oldWaiters = waiters;
- waiters = null;
- }
- for (BiConsumer<? super T, ? super Throwable> waiter : oldWaiters) {
- waiter.accept(newValue, null);
- }
- return true;
+ return completableFuture.kafkaComplete(newValue);
}
@Override
public boolean completeExceptionally(Throwable newException) {
- List<BiConsumer<? super T, ? super Throwable>> oldWaiters;
- synchronized (this) {
- if (done)
- return false;
- exception = newException;
- done = true;
- oldWaiters = waiters;
- waiters = null;
- }
- for (BiConsumer<? super T, ? super Throwable> waiter : oldWaiters) {
- waiter.accept(null, newException);
- }
- return true;
+ // CF#get() always wraps the _cause_ of a CompletionException in EE (which KF does not)
Review comment:
Not sure what EE is here.
##########
File path: clients/src/main/java/org/apache/kafka/common/internals/KafkaFutureImpl.java
##########
@@ -267,50 +173,77 @@ public T get() throws InterruptedException, ExecutionException {
@Override
public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException,
TimeoutException {
- SingleWaiter<T> waiter = new SingleWaiter<>();
- addWaiter(waiter);
- return waiter.await(timeout, unit);
+ try {
+ return completableFuture.get(timeout, unit);
+ } catch (ExecutionException e) {
+ maybeRewrapAndThrow(e.getCause());
+ throw e;
+ }
}
/**
* Returns the result value (or throws any encountered exception) if completed, else returns
* the given valueIfAbsent.
*/
@Override
- public synchronized T getNow(T valueIfAbsent) throws InterruptedException, ExecutionException {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- return valueIfAbsent;
+ public synchronized T getNow(T valueIfAbsent) throws ExecutionException {
+ try {
+ return completableFuture.getNow(valueIfAbsent);
+ } catch (CompletionException e) {
+ maybeRewrapAndThrow(e.getCause());
+ // Note, unlike CF#get() which throws ExecutionException, CF#getNow() throws CompletionException
+ // thus needs rewrapping to conform to KafkaFuture API, where KF#getNow() throws ExecutionException.
+ throw new ExecutionException(e.getCause());
+ }
}
/**
* Returns true if this CompletableFuture was cancelled before it completed normally.
*/
@Override
public synchronized boolean isCancelled() {
- return exception instanceof CancellationException;
+ if (isDependant) {
+ Throwable exception;
+ try {
+ completableFuture.getNow(null);
+ return false;
+ } catch (Exception e) {
+ exception = e;
+ }
+ return exception instanceof CompletionException
+ && exception.getCause() instanceof CancellationException;
+ } else {
+ return completableFuture.isCancelled();
+ }
}
/**
* Returns true if this CompletableFuture completed exceptionally, in any way.
*/
@Override
public synchronized boolean isCompletedExceptionally() {
- return exception != null;
+ return completableFuture.isCompletedExceptionally();
}
/**
* Returns true if completed in any fashion: normally, exceptionally, or via cancellation.
*/
@Override
public synchronized boolean isDone() {
- return done;
+ return completableFuture.isDone();
}
@Override
public String toString() {
- return String.format("KafkaFuture{value=%s,exception=%s,done=%b}", value, exception, done);
+ T value = null;
+ Throwable ex = null;
Review comment:
the naming used above seems better here
```suggestion
Throwable exception = null;
```
##########
File path: clients/src/main/java/org/apache/kafka/common/internals/KafkaFutureImpl.java
##########
@@ -267,50 +173,77 @@ public T get() throws InterruptedException, ExecutionException {
@Override
public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException,
TimeoutException {
- SingleWaiter<T> waiter = new SingleWaiter<>();
- addWaiter(waiter);
- return waiter.await(timeout, unit);
+ try {
+ return completableFuture.get(timeout, unit);
+ } catch (ExecutionException e) {
+ maybeRewrapAndThrow(e.getCause());
+ throw e;
+ }
}
/**
* Returns the result value (or throws any encountered exception) if completed, else returns
* the given valueIfAbsent.
*/
@Override
- public synchronized T getNow(T valueIfAbsent) throws InterruptedException, ExecutionException {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- return valueIfAbsent;
+ public synchronized T getNow(T valueIfAbsent) throws ExecutionException {
+ try {
+ return completableFuture.getNow(valueIfAbsent);
+ } catch (CompletionException e) {
+ maybeRewrapAndThrow(e.getCause());
+ // Note, unlike CF#get() which throws ExecutionException, CF#getNow() throws CompletionException
+ // thus needs rewrapping to conform to KafkaFuture API, where KF#getNow() throws ExecutionException.
+ throw new ExecutionException(e.getCause());
+ }
}
/**
* Returns true if this CompletableFuture was cancelled before it completed normally.
*/
@Override
public synchronized boolean isCancelled() {
- return exception instanceof CancellationException;
+ if (isDependant) {
+ Throwable exception;
Review comment:
I believe just returning from the catch branch is fine. No need for this variable. (you return from any path)
##########
File path: clients/src/main/java/org/apache/kafka/common/internals/KafkaFutureImpl.java
##########
@@ -27,217 +28,107 @@
/**
* A flexible future which supports call chaining and other asynchronous programming patterns.
- * This will eventually become a thin shim on top of Java 8's CompletableFuture.
*/
public class KafkaFutureImpl<T> extends KafkaFuture<T> {
- /**
- * A convenience method that throws the current exception, wrapping it if needed.
- *
- * In general, KafkaFuture throws CancellationException and InterruptedException directly, and
- * wraps all other exceptions in an ExecutionException.
- */
- private static void wrapAndThrow(Throwable t) throws InterruptedException, ExecutionException {
- if (t instanceof CancellationException) {
- throw (CancellationException) t;
- } else if (t instanceof InterruptedException) {
- throw (InterruptedException) t;
- } else {
- throw new ExecutionException(t);
- }
- }
- private static class Applicant<A, B> implements BiConsumer<A, Throwable> {
- private final BaseFunction<A, B> function;
- private final KafkaFutureImpl<B> future;
+ private final KafkaCompletableFuture<T> completableFuture;
- Applicant(BaseFunction<A, B> function, KafkaFutureImpl<B> future) {
- this.function = function;
- this.future = future;
- }
+ private final boolean isDependant;
- @Override
- public void accept(A a, Throwable exception) {
- if (exception != null) {
- future.completeExceptionally(exception);
- } else {
- try {
- B b = function.apply(a);
- future.complete(b);
- } catch (Throwable t) {
- future.completeExceptionally(t);
- }
- }
- }
+ public KafkaFutureImpl() {
+ this(false, new KafkaCompletableFuture<>());
}
- private static class SingleWaiter<R> implements BiConsumer<R, Throwable> {
- private R value = null;
- private Throwable exception = null;
- private boolean done = false;
-
- @Override
- public synchronized void accept(R newValue, Throwable newException) {
- this.value = newValue;
- this.exception = newException;
- this.done = true;
- this.notifyAll();
- }
-
- synchronized R await() throws InterruptedException, ExecutionException {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- this.wait();
- }
- }
-
- R await(long timeout, TimeUnit unit)
- throws InterruptedException, ExecutionException, TimeoutException {
- long startMs = System.currentTimeMillis();
- long waitTimeMs = unit.toMillis(timeout);
- long delta = 0;
- synchronized (this) {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- if (delta >= waitTimeMs) {
- throw new TimeoutException();
- }
- this.wait(waitTimeMs - delta);
- delta = System.currentTimeMillis() - startMs;
- }
- }
- }
+ public KafkaFutureImpl(KafkaCompletableFuture<T> completableFuture) {
+ this(false, completableFuture);
}
- /**
- * True if this future is done.
- */
- private boolean done = false;
-
- /**
- * The value of this future, or null. Protected by the object monitor.
- */
- private T value = null;
-
- /**
- * The exception associated with this future, or null. Protected by the object monitor.
- */
- private Throwable exception = null;
+ private KafkaFutureImpl(boolean isDependant, KafkaCompletableFuture<T> completableFuture) {
+ this.isDependant = isDependant;
+ this.completableFuture = completableFuture;
+ }
- /**
- * A list of objects waiting for this future to complete (either successfully or
- * exceptionally). Protected by the object monitor.
- */
- private List<BiConsumer<? super T, ? super Throwable>> waiters = new ArrayList<>();
+ @Override
+ public CompletionStage<T> toCompletionStage() {
+ return completableFuture;
+ }
/**
* Returns a new KafkaFuture that, when this future completes normally, is executed with this
* futures's result as the argument to the supplied function.
*/
@Override
public <R> KafkaFuture<R> thenApply(BaseFunction<T, R> function) {
- KafkaFutureImpl<R> future = new KafkaFutureImpl<>();
- addWaiter(new Applicant<>(function, future));
- return future;
+ CompletableFuture<R> completableFuture = this.completableFuture.thenApply((java.util.function.Function<? super T, ? extends R>) value -> {
+ try {
+ return function.apply(value);
+ } catch (Throwable t) {
+ if (t instanceof CompletionException) {
+ throw new CompletionException(t);
+ } else {
+ throw t;
+ }
+ }
+ });
+ return new KafkaFutureImpl<>(true, toKafkaCompletableFuture(completableFuture));
}
- public <R> void copyWith(KafkaFuture<R> future, BaseFunction<R, T> function) {
- KafkaFutureImpl<R> futureImpl = (KafkaFutureImpl<R>) future;
- futureImpl.addWaiter(new Applicant<>(function, this));
+ private <U> KafkaCompletableFuture<U> toKafkaCompletableFuture(CompletableFuture<U> tCompletableFuture) {
+ KafkaCompletableFuture<U> res;
Review comment:
the fact that two variables are used here must be a remainder of an earlier iteration.
```suggestion
KafkaCompletableFuture<U> result;
```
can be declared here at the top level and we can remove the inner declaration.
##########
File path: clients/src/main/java/org/apache/kafka/common/internals/KafkaFutureImpl.java
##########
@@ -27,217 +28,107 @@
/**
* A flexible future which supports call chaining and other asynchronous programming patterns.
- * This will eventually become a thin shim on top of Java 8's CompletableFuture.
*/
public class KafkaFutureImpl<T> extends KafkaFuture<T> {
- /**
- * A convenience method that throws the current exception, wrapping it if needed.
- *
- * In general, KafkaFuture throws CancellationException and InterruptedException directly, and
- * wraps all other exceptions in an ExecutionException.
- */
- private static void wrapAndThrow(Throwable t) throws InterruptedException, ExecutionException {
- if (t instanceof CancellationException) {
- throw (CancellationException) t;
- } else if (t instanceof InterruptedException) {
- throw (InterruptedException) t;
- } else {
- throw new ExecutionException(t);
- }
- }
- private static class Applicant<A, B> implements BiConsumer<A, Throwable> {
- private final BaseFunction<A, B> function;
- private final KafkaFutureImpl<B> future;
+ private final KafkaCompletableFuture<T> completableFuture;
- Applicant(BaseFunction<A, B> function, KafkaFutureImpl<B> future) {
- this.function = function;
- this.future = future;
- }
+ private final boolean isDependant;
- @Override
- public void accept(A a, Throwable exception) {
- if (exception != null) {
- future.completeExceptionally(exception);
- } else {
- try {
- B b = function.apply(a);
- future.complete(b);
- } catch (Throwable t) {
- future.completeExceptionally(t);
- }
- }
- }
+ public KafkaFutureImpl() {
+ this(false, new KafkaCompletableFuture<>());
}
- private static class SingleWaiter<R> implements BiConsumer<R, Throwable> {
- private R value = null;
- private Throwable exception = null;
- private boolean done = false;
-
- @Override
- public synchronized void accept(R newValue, Throwable newException) {
- this.value = newValue;
- this.exception = newException;
- this.done = true;
- this.notifyAll();
- }
-
- synchronized R await() throws InterruptedException, ExecutionException {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- this.wait();
- }
- }
-
- R await(long timeout, TimeUnit unit)
- throws InterruptedException, ExecutionException, TimeoutException {
- long startMs = System.currentTimeMillis();
- long waitTimeMs = unit.toMillis(timeout);
- long delta = 0;
- synchronized (this) {
- while (true) {
- if (exception != null)
- wrapAndThrow(exception);
- if (done)
- return value;
- if (delta >= waitTimeMs) {
- throw new TimeoutException();
- }
- this.wait(waitTimeMs - delta);
- delta = System.currentTimeMillis() - startMs;
- }
- }
- }
+ public KafkaFutureImpl(KafkaCompletableFuture<T> completableFuture) {
+ this(false, completableFuture);
}
- /**
- * True if this future is done.
- */
- private boolean done = false;
-
- /**
- * The value of this future, or null. Protected by the object monitor.
- */
- private T value = null;
-
- /**
- * The exception associated with this future, or null. Protected by the object monitor.
- */
- private Throwable exception = null;
+ private KafkaFutureImpl(boolean isDependant, KafkaCompletableFuture<T> completableFuture) {
+ this.isDependant = isDependant;
+ this.completableFuture = completableFuture;
+ }
- /**
- * A list of objects waiting for this future to complete (either successfully or
- * exceptionally). Protected by the object monitor.
- */
- private List<BiConsumer<? super T, ? super Throwable>> waiters = new ArrayList<>();
+ @Override
+ public CompletionStage<T> toCompletionStage() {
+ return completableFuture;
+ }
/**
* Returns a new KafkaFuture that, when this future completes normally, is executed with this
* futures's result as the argument to the supplied function.
*/
@Override
public <R> KafkaFuture<R> thenApply(BaseFunction<T, R> function) {
- KafkaFutureImpl<R> future = new KafkaFutureImpl<>();
- addWaiter(new Applicant<>(function, future));
- return future;
+ CompletableFuture<R> completableFuture = this.completableFuture.thenApply((java.util.function.Function<? super T, ? extends R>) value -> {
Review comment:
Not a big fan of variable shadowing, which below you avoid by calling the local variable `tCompletableFuture`. Probably good idea to apply the naming here to and remove `this.`
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: jira-unsubscribe@kafka.apache.org
For queries about this service, please contact Infrastructure at:
users@infra.apache.org