Package com.apple.foundationdb.record.logging

Class CompletionExceptionLogHelper

java.lang.Object

com.apple.foundationdb.record.logging.CompletionExceptionLogHelper

@API(MAINTAINED)
public class CompletionExceptionLogHelper
extends Object

Helper class for helping with logging of CompletionExceptions. The CompletionException has a stack trace that indicates the call to a wait point, such as FDBRecordContext.asyncToSync(com.apple.foundationdb.record.provider.common.StoreTimer.Wait, java.util.concurrent.CompletableFuture<T>), which may be the only indication of what the caller was actually doing. But the cause of this exception is the one to analyze and wrap in an appropriate subclass of RecordCoreException, so that is returned, after remembering the original exception as a suppressed exception.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	CompletionExceptionLogHelper.IgnoredSuppressedExceptionCount	A special "exception" to record the number of suppressed exceptions that were not recorded due to the maxSuppressedCount.

Method Summary

Modifier and Type	Method	Description
static Throwable	asCause(CompletionException ex)	Return the cause of the given exception and also arrange for the original exception to be in the suppressed chain.
static Throwable	asCause(ExecutionException ex)	Return the cause of the given exception and also arrange for the original exception to be in the suppressed chain.
static void	forceSetMaxSuppressedCountForTesting(int count)	Change the maximum number of suppressed exceptions to add to any given exception, even if the maximum has already been set.
static void	setAddSuppressed(boolean addSuppressed)	Change whether Throwable.addSuppressed(java.lang.Throwable) is used.
static boolean	setMaxSuppressedCountIfNotSet(int count)	Change the maximum number of suppressed exceptions to add to any given exception, if this maximum has not already been set.

Methods inherited from class java.lang.Object

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

Method Detail

setAddSuppressed

public static void setAddSuppressed(boolean addSuppressed)

Change whether Throwable.addSuppressed(java.lang.Throwable) is used. When enabled, the exception graph will have a circularity. This can cause problems for some logging frameworks and so may need to be disabled if using one of them.

Parameters:

addSuppressed - true to use addSuppressed to give more information in logs

setMaxSuppressedCountIfNotSet

public static boolean setMaxSuppressedCountIfNotSet(int count)

Change the maximum number of suppressed exceptions to add to any given exception, if this maximum has not already been set. Return whether or not the maximum was changed. This method only changes behavior when addSuppressed is true.

Parameters:

count - the new maximum count

Returns:

true if the count was changed and false if it was not

forceSetMaxSuppressedCountForTesting

@API(INTERNAL)
public static void forceSetMaxSuppressedCountForTesting(int count)

Change the maximum number of suppressed exceptions to add to any given exception, even if the maximum has already been set. This should be done with extreme care: asCauseThrowable(Throwable) may misbehave if it handles exceptions before and after this method is called with the same cause. It should ONLY be used for testing without restarting the JVM.

Parameters:

count - the new maximum count

asCause

public static Throwable asCause(@Nonnull
                                CompletionException ex)

Return the cause of the given exception and also arrange for the original exception to be in the suppressed chain.

Parameters:

ex - an exception from CompletableFuture.join() or the like

Returns:

a throwable suitable for use as the cause of a wrapped exception

asCause

public static Throwable asCause(@Nonnull
                                ExecutionException ex)

Return the cause of the given exception and also arrange for the original exception to be in the suppressed chain. However, if the given exception's cause already has the maximum number of suppressed exceptions specified by setMaxSuppressedCountIfNotSet(int), then the given exception is not added to the suppressed chain and the exception counting the number of ignored exceptions is incremented instead.

Parameters:

ex - an exception from CompletableFuture.get() or the like

Returns:

a throwable suitable for use as the cause of a wrapped exception