com.firefly.utils.concurrent.IteratingNestedCallback Maven / Gradle / Ivy
package com.firefly.utils.concurrent;
/**
* Iterating Nested Callback.
*
* This specialized callback is used when breaking up an asynchronous task into
* smaller asynchronous tasks. A typical pattern is that a successful callback
* is used to schedule the next sub task, but if that task completes quickly and
* uses the calling thread to callback the success notification, this can result
* in a growing stack depth.
*
*
* To avoid this issue, this callback uses an AtomicBoolean to note if the
* success callback has been called during the processing of a sub task, and if
* so then the processing iterates rather than recurses.
*
*
* This callback is passed to the asynchronous handling of each sub task and a
* call the {@link #succeeded()} on this call back represents completion of the
* subtask. Only once all the subtasks are completed is the
* {@link Callback#succeeded()} method called on the {@link Callback} instance
* passed the the {@link #IteratingNestedCallback(Callback)} constructor.
*
*
*/
public abstract class IteratingNestedCallback extends IteratingCallback {
final Callback _callback;
public IteratingNestedCallback(Callback callback) {
_callback = callback;
}
@Override
public boolean isNonBlocking() {
return _callback.isNonBlocking();
}
@Override
protected void onCompleteSuccess() {
_callback.succeeded();
}
@Override
protected void onCompleteFailure(Throwable x) {
_callback.failed(x);
}
@Override
public String toString() {
return String.format("%s@%x", getClass().getSimpleName(), hashCode());
}
}