org.apache.hedwig.util

Class CallbackUtils

java.lang.Object

org.apache.hedwig.util.CallbackUtils

public class CallbackUtils
extends Object

Constructor Summary

Constructors

Constructor and Description
CallbackUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static <T> Callback<Void>	curry(Callback<T> cb, T result) Return a Callback that just calls the given Callback cb with the bound result.
static Callback<Void>	logger(org.slf4j.Logger logger, String successMsg, String failureMsg) Logs what happened (no continuation).
static <T> Callback<T>	logger(org.slf4j.Logger logger, String successMsg, String failureMsg, Callback<T> cont) Logs what happened before continuing the callback chain.
static Callback<Void>	multiCallback(int expected, Callback<Void> cb, Object ctx) A callback that waits for all of a number of events to fire.
static Callback<Void>	multiCallback(int expected, Callback<Void> cb, Object ctx, org.slf4j.Logger logger, String successMsg, String failureMsg, Runnable eagerErrorHandler) A callback that waits for all of a number of events to fire.
static Callback<Void>	multinCallback(int expected, Callback<Void> cb, Object ctx, Runnable eagerErrorHandler) A callback that waits for all of a number of events to fire.
static Callback<Void>	nop() A do-nothing callback.

Methods inherited from class java.lang.Object

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

Constructor Detail

CallbackUtils

public CallbackUtils()

Method Detail

multiCallback

public static Callback<Void> multiCallback(int expected,
                           Callback<Void> cb,
                           Object ctx,
                           org.slf4j.Logger logger,
                           String successMsg,
                           String failureMsg,
                           Runnable eagerErrorHandler)

A callback that waits for all of a number of events to fire. If any fail, then fail the final callback with a composite exception. TODO: change this to use any Exception and make CompositeException generic, not a PubSubException.

Parameters:

expected - Number of expected callbacks.

cb - The final callback to call.

ctx -

logger - May be null.

successMsg - If not null, then this is logged on success.

failureMsg - If not null, then this is logged on failure.

eagerErrorHandler - If not null, then this will be executed after the first failure (but before the final failure callback). Useful for releasing resources, etc. as soon as we know the composite operation is doomed.

Returns:

the generated callback

multiCallback

public static Callback<Void> multiCallback(int expected,
                           Callback<Void> cb,
                           Object ctx)

A callback that waits for all of a number of events to fire. If any fail, then fail the final callback with a composite exception.

multinCallback

public static Callback<Void> multinCallback(int expected,
                            Callback<Void> cb,
                            Object ctx,
                            Runnable eagerErrorHandler)

A callback that waits for all of a number of events to fire. If any fail, then fail the final callback with a composite exception.

nop

public static Callback<Void> nop()

A do-nothing callback.

logger

public static <T> Callback<T> logger(org.slf4j.Logger logger,
                     String successMsg,
                     String failureMsg,
                     Callback<T> cont)

Logs what happened before continuing the callback chain.

logger

public static Callback<Void> logger(org.slf4j.Logger logger,
                    String successMsg,
                    String failureMsg)

Logs what happened (no continuation).

curry

public static <T> Callback<Void> curry(Callback<T> cb,
                       T result)

Return a Callback that just calls the given Callback cb with the bound result.