net.markenwerk.commons.interfaces

Interface Callback<Callee,Result>

Type Parameters:

Callee - The type of the original

Result - The type of the result of the process.

public interface Callback<Callee,Result>

For an arbitrary process, that will eventually yield a result, a Callback is used, to convey that result from the executor of the process (the callee) back to the initiator of the process (the caller).

Depending on the concrete scenario, the caller may reuse the same instance of Callback for multiple processes and even for the same callee..

In most scenarios, the callee must eventually call onResult(Object, Object), at least once.

A useful exception to this rule is, when the callee can ensure, that the result wont't be needed by the caller, because the caller itself is not needed anymore. This is usually implemented by placing the Callback in a WeakReference. Because using anonymous instances of Callback will most likely fail in this situation, it should be noted in the contract of the method, that takes the Callback as an argument.

The callee may call onResult(Object, Object), more than once, depending o the concrete scenario, to convey partial or updated results. This should be noted in the contract of the method, takes the Callback as an argument.

The callee must not call onResult(Object, Object) more than once for the same result.

Since:

1.0.0

Author:

Torsten Krause (tk at markenwerk dot net)

Method Summary

Modifier and Type	Method and Description
void	onResult(Callee callee, Result result) Called by the callee if and when a result is available.

Method Detail

onResult

void onResult(Callee callee,
              Result result)

Called by the callee if and when a result is available.

Implementers must not throw any exceptions.

Parameters:

callee - The callee.

result - The result.