com.github.phantomthief.scope

Class ScopeAsyncRetry

java.lang.Object

com.github.phantomthief.scope.ScopeAsyncRetry

public class ScopeAsyncRetry
extends Object

支持 Scope 级联，并且支持单次调用独立设置超时的异步重试封装

使用方法:

 class MyClass {

   private final ScopeAsyncRetry retrier = ScopeAsyncRetry.shared();
   private final ListeningExecutorService executor = listeningDecorator(newFixedThreadPool(10);

   ListenableFuture<String> asyncCall() {
     return executor.submit(() -> {
       sleepUninterruptibly(ThreadLocalRandom.current().nextLong(150L), MILLISECONDS);
       return "myTest"
     });
   }

   void foo() throws ExecutionException, TimeoutException {
     ListenableFuture<String> future = retrier.callWithRetry(100, retryNTimes(3), () -> asyncCall());
     String unwrapped = getUninterruptibly(future, 200, MILLISECONDS);
     System.out.println("result is:" + unwrapped);
   }
 }

 
 

注意: 如果最终外部的ListenableFuture.get(timeout)没有超时，但是内部请求都失败了，则上抛 会上抛 ExecutionException 并包含最后一次重试的结果 特别的，如果最后一次请求超时 Throwable.getCause() 为 TimeoutException

注意: 需要重试的方法应该是幂等的操作，不应有任何副作用。

Author:

myco Created on 2019-01-20

Method Summary

Modifier and Type	Method and Description
<T,X extends Throwable> com.google.common.util.concurrent.ListenableFuture<T>	callWithRetry(long singleCallTimeoutMs, RetryPolicy retryPolicy, com.github.phantomthief.util.ThrowableSupplier<com.google.common.util.concurrent.ListenableFuture<T>,X> func) 带重试的调用
<T,X extends Throwable> com.google.common.util.concurrent.ListenableFuture<T>	callWithRetry(long singleCallTimeoutMs, RetryPolicy retryPolicy, com.github.phantomthief.util.ThrowableSupplier<com.google.common.util.concurrent.ListenableFuture<T>,X> func, com.google.common.util.concurrent.FutureCallback<T> eachRetryCallback)
static ScopeAsyncRetry	createScopeAsyncRetry(ScheduledExecutorService executor) Deprecated.
static ScopeAsyncRetry	createScopeAsyncRetry(ScheduledExecutorService executor, Executor callbackExecutor)
static ScopeAsyncRetry	shared() 共享的 ScopeAsyncRetry 实例

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

createScopeAsyncRetry

@Deprecated
public static ScopeAsyncRetry createScopeAsyncRetry(@Nonnegative
                                                                ScheduledExecutorService executor)

Deprecated.

因为使用 directExecutor 执行 callback 操作，导致 callback 任务占用 ScheduledExecutorService， 从而导致超时控制的有效性可能会随着负载提高而急剧下降 请使用 createScopeAsyncRetry(ScheduledExecutorService, Executor)

createScopeAsyncRetry

public static ScopeAsyncRetry createScopeAsyncRetry(@Nonnegative
                                                    ScheduledExecutorService executor,
                                                    Executor callbackExecutor)

shared

public static ScopeAsyncRetry shared()

共享的 ScopeAsyncRetry 实例

建议不同业务使用不同的实例，因为其中通过 ScheduledExecutorService 来检测超时 和 实现间隔重试 大量使用共享实例，这里可能成为瓶颈

callWithRetry

@Nonnull
public <T,X extends Throwable> com.google.common.util.concurrent.ListenableFuture<T> callWithRetry(long singleCallTimeoutMs,
                                                                                                            RetryPolicy retryPolicy,
                                                                                                            @Nonnull
                                                                                                            com.github.phantomthief.util.ThrowableSupplier<com.google.common.util.concurrent.ListenableFuture<T>,X> func)

带重试的调用

Parameters:

singleCallTimeoutMs - 单次调用超时限制，单位：ms

func - 需要重试的调用

Returns:

带重试的future

callWithRetry

@Nonnull
public <T,X extends Throwable> com.google.common.util.concurrent.ListenableFuture<T> callWithRetry(long singleCallTimeoutMs,
                                                                                                            RetryPolicy retryPolicy,
                                                                                                            @Nonnull
                                                                                                            com.github.phantomthief.util.ThrowableSupplier<com.google.common.util.concurrent.ListenableFuture<T>,X> func,
                                                                                                            @Nullable
                                                                                                            com.google.common.util.concurrent.FutureCallback<T> eachRetryCallback)