| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.safeguard.impl.asynchronous; |
| |
| import static java.util.Optional.ofNullable; |
| import static java.util.concurrent.TimeUnit.NANOSECONDS; |
| |
| import java.io.Serializable; |
| import java.util.Map; |
| import java.util.concurrent.CompletableFuture; |
| import java.util.concurrent.CompletionStage; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.Executor; |
| import java.util.concurrent.Future; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.atomic.AtomicReference; |
| import java.util.function.Consumer; |
| |
| import javax.interceptor.InvocationContext; |
| |
| import org.apache.safeguard.impl.interceptor.IdGeneratorInterceptor; |
| import org.eclipse.microprofile.faulttolerance.exceptions.FaultToleranceDefinitionException; |
| |
| public abstract class BaseAsynchronousInterceptor implements Serializable { |
| public abstract Executor getExecutor(InvocationContext context); |
| |
| protected Object around(final InvocationContext context, final String id) { |
| final Class<?> returnType = context.getMethod().getReturnType(); |
| if (CompletionStage.class.isAssignableFrom(returnType)) { |
| final ExtendedCompletableFuture<Object> future = newCompletableFuture(context); |
| getExecutor(context).execute(() -> { |
| try { |
| future.before(); |
| final Object proceed = context.proceed(); |
| final CompletionStage<?> stage = CompletionStage.class.cast(proceed); |
| stage.handle((r, e) -> { |
| future.after(); |
| if (e != null) { |
| ofNullable(getErrorHandler(context.getContextData())) |
| .map(eh -> { |
| if (Exception.class.isInstance(e)) { |
| try { |
| eh.apply(Exception.class.cast(e)); |
| } catch (final Exception e1) { |
| future.completeExceptionally(e1); |
| } |
| } else { |
| future.completeExceptionally(e); |
| } |
| return true; |
| }) |
| .orElseGet(() -> future.completeExceptionally(e)); |
| } else { |
| future.complete(r); |
| } |
| return null; |
| }); |
| } catch (final Exception e) { |
| future.completeExceptionally(e); |
| } |
| }); |
| return future; |
| } |
| if (Future.class.isAssignableFrom(returnType)) { |
| final FutureWrapper<Object> facade = newFuture(context, context.getContextData()); |
| context.getContextData().put(FutureWrapper.class.getName() + "_" + id, facade); |
| getExecutor(context).execute(new AsyncTask(context, facade)); |
| return facade; |
| } |
| throw new FaultToleranceDefinitionException( |
| "Unsupported return type: " + returnType + " (from: " + context.getMethod() + ")." + |
| "Should be Future or CompletionStage."); |
| } |
| |
| private static ErrorHandler<Exception, Future<?>> getErrorHandler(final Map<String, Object> contextData) { |
| return ErrorHandler.class.cast( |
| contextData.get(BaseAsynchronousInterceptor.BaseFuture.class.getName() + ".errorHandler_" + |
| contextData.get(IdGeneratorInterceptor.class.getName()))); |
| } |
| |
| protected FutureWrapper<Object> newFuture(final InvocationContext context, |
| final Map<String, Object> data) { |
| return new FutureWrapper<>(data); |
| } |
| |
| protected ExtendedCompletableFuture<Object> newCompletableFuture(final InvocationContext context) { |
| return new ExtendedCompletableFuture<>(); |
| } |
| |
| @FunctionalInterface |
| public interface ErrorHandler<A, B> { |
| B apply(A a) throws Exception; |
| } |
| |
| public interface BaseFuture { |
| default void before() { |
| |
| } |
| |
| default void after() { |
| |
| } |
| } |
| |
| public static class ExtendedCompletableFuture<T> extends CompletableFuture<T> implements BaseFuture { |
| } |
| |
| public static class FutureWrapper<T> implements Future<T>, BaseFuture { |
| private FutureWrapper<?> parent; |
| private final AtomicReference<Future<T>> delegate = new AtomicReference<>(); |
| private final AtomicReference<Consumer<Future<T>>> cancelled = new AtomicReference<>(); |
| private final CountDownLatch latch = new CountDownLatch(1); |
| private final Map<String, Object> data; |
| |
| public FutureWrapper(final Map<String, Object> data) { |
| this.data = data; |
| } |
| |
| public FutureWrapper<?> getParent() { |
| return parent; |
| } |
| |
| public void setParent(final FutureWrapper<?> parent) { |
| if (this.parent != null) { |
| this.parent.setParent(parent); |
| } |
| this.parent = parent; |
| } |
| |
| public void setDelegate(final Future<T> delegate) { |
| final Consumer<Future<T>> cancelledTask = cancelled.get(); |
| if (cancelledTask != null) { |
| cancelledTask.accept(delegate); |
| } |
| after(); |
| this.delegate.set(delegate); |
| this.latch.countDown(); |
| } |
| |
| @Override |
| public boolean cancel(final boolean mayInterruptIfRunning) { |
| cancelled.set(f -> f.cancel(mayInterruptIfRunning)); |
| return true; |
| } |
| |
| @Override |
| public boolean isCancelled() { |
| return cancelled.get() != null; |
| } |
| |
| @Override |
| public boolean isDone() { |
| final Future<T> future = delegate.get(); |
| return future != null && future.isDone() && getErrorHandler(data) == null; |
| } |
| |
| @Override |
| public T get() throws InterruptedException, ExecutionException { |
| latch.await(); |
| final Future<T> future = delegate.get(); |
| try { |
| return future.get(); |
| } catch (final ExecutionException ee) { |
| delegate.set(onException(ee)); |
| return delegate.get().get(); |
| } |
| } |
| |
| @Override |
| public T get(final long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException { |
| final long end = System.nanoTime() + unit.toNanos(timeout); |
| final boolean latchWait = latch.await(timeout, unit); |
| final long readyNs = System.nanoTime(); |
| if (!latchWait || readyNs > end) { |
| throw new TimeoutException(); |
| } |
| try { |
| return delegate.get().get(Math.max(0, end - readyNs), NANOSECONDS); |
| } catch (final ExecutionException ee) { |
| delegate.set(onException(ee)); |
| final long now = System.nanoTime(); |
| if (now > end) { |
| throw new TimeoutException(); |
| } |
| return delegate.get().get(Math.max(0, end - now), NANOSECONDS); |
| } |
| } |
| |
| // todo: revise |
| protected Future<T> onException(final Throwable cause) { |
| if (!Exception.class.isInstance(cause)) { |
| if (Error.class.isInstance(cause)) { |
| throw Error.class.cast(cause); |
| } |
| throw new IllegalStateException(cause); |
| } |
| final Exception ex = Exception.class.cast(cause); |
| final ErrorHandler<Exception, Future<?>> handler = getErrorHandler(data); |
| if (handler != null) { |
| try { |
| return (Future<T>) handler.apply(ex); |
| } catch (final Exception e) { |
| if (RuntimeException.class.isInstance(e)) { |
| throw RuntimeException.class.cast(e); |
| } |
| if (Error.class.isInstance(e)) { |
| throw Error.class.cast(e); |
| } |
| if (ExecutionException.class.isInstance(cause) && cause.getCause() != cause) { |
| return failAsFuture(cause); |
| } |
| throw new IllegalStateException(e); |
| } |
| } |
| if (ExecutionException.class.isInstance(cause) && cause.getCause() != cause) { |
| final Throwable throwable = ExecutionException.class.cast(cause).getCause(); |
| return onException(throwable); |
| } |
| if (RuntimeException.class.isInstance(cause)) { |
| throw RuntimeException.class.cast(cause); |
| } |
| throw new IllegalStateException(cause); // unreachable - just for compiler |
| } |
| |
| private Future<T> failAsFuture(final Throwable cause) { |
| final Throwable throwable = ExecutionException.class.cast(cause).getCause(); |
| final ExtendedCompletableFuture<T> future = new ExtendedCompletableFuture<>(); |
| future.completeExceptionally(throwable); |
| return future; |
| } |
| |
| public void failed(final Exception exception) { |
| final ExtendedCompletableFuture<T> delegate = new ExtendedCompletableFuture<>(); |
| delegate.completeExceptionally(exception); |
| setDelegate(delegate); |
| latch.countDown(); |
| } |
| } |
| |
| public static class AsyncTask implements Runnable { |
| private final InvocationContext context; |
| private final FutureWrapper<Object> facade; |
| |
| public AsyncTask(final InvocationContext context, final FutureWrapper<Object> facade) { |
| this.context = context; |
| this.facade = facade; |
| } |
| |
| public FutureWrapper<Object> getFacade() { |
| return facade; |
| } |
| |
| @Override |
| public void run() { |
| final Object proceed; |
| try { |
| facade.before(); |
| proceed = context.proceed(); |
| facade.setDelegate(Future.class.cast(proceed)); |
| } catch (final Exception e) { |
| final CompletableFuture<Object> failingFuture = new CompletableFuture<>(); |
| failingFuture.completeExceptionally(e); |
| facade.setDelegate(failingFuture); |
| } |
| } |
| } |
| } |