Package org.kiwiproject.concurrent

Class AsyncException

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

org.kiwiproject.concurrent.AsyncException

All Implemented Interfaces:

Serializable

public class AsyncException
extends RuntimeException

A subclass RuntimeException used to indicate problems in asynchronous code.

The cause will generally be an InterruptedException or one of the checked exceptions thrown by Java's futures, specifically either TimeoutException or ExecutionException

See Also:

• Serialized Form

Implementation Note:

Sadly, we cannot make this class generic, i.e. AsyncException<T>. It will not compile; the compiler reports the following error: "a generic class may not extend java.lang.Throwable". However, we can fake it by declaring getFuture() in a generic manner (and suppressing the unchecked warning). This means you could still receive a ClassCastException at runtime if you attempt a cast to an invalid type.

Constructor Summary

Constructors

Constructor	Description
AsyncException(String message, @Nullable CompletableFuture<?> future)	Construct instance with given message and future.
AsyncException(String message, Throwable cause, @Nullable CompletableFuture<?> future)	Construct instance with given message, cause, and future.

Method Summary

Modifier and Type	Method	Description
<T> @Nullable CompletableFuture<T>	getFuture()	The future which causes the exception.
boolean	hasFuture()	Does this AsyncException contain a future?

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

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

Constructor Details

AsyncException

public AsyncException(String message,
 @Nullable CompletableFuture<?> future)

Construct instance with given message and future.

Parameters:

message - the exception message

future - the CompletableFuture that caused the error, may be null

AsyncException

public AsyncException(String message,
 Throwable cause,
 @Nullable CompletableFuture<?> future)

Construct instance with given message, cause, and future.

Parameters:

message - the exception message

cause - the original cause of the exception

future - the CompletableFuture that caused the error, may be null

Method Details

hasFuture

public boolean hasFuture()

Does this AsyncException contain a future?

Returns:

true if this instance contains a CompletableFuture

API Note:

When a single asynchronous operation is performed and there is only one future, then callers can expect this to contain a CompletableFuture and return true. When multiple futures are acted upon (e.g. waiting for all to complete), callers should expect this instance not to contain a CompletableFuture and this method to return false.

getFuture

public <T> @Nullable CompletableFuture<T> getFuture()

The future which causes the exception. May be null. Use hasFuture() to check if this instance contains a future.

Type Parameters:

T - the generic type of the CompletableFuture

Returns:

the future causing this exception, or null

Throws:

ClassCastException - if the type you assign you is not the actual type