Package org.apache.ignite.compute

Interface ComputeJobContinuation

All Known Subinterfaces:

ComputeJobContext

All Known Implementing Classes:

ComputeJobContinuationAdapter

public interface ComputeJobContinuation

Defines continuation support for grid job context.

Method Summary

Modifier and Type	Method	Description
void	callcc()	Resumes job if it was held by holdcc() method.
boolean	heldcc()	Checks if job execution has been temporarily held (suspended).
<T> T	holdcc()	Holds (suspends) a given job indefinitely until callcc() is called.
<T> T	holdcc(long timeout)	Holds (suspends) a given job for specified timeout or until callcc() is called.

Method Detail

heldcc

boolean heldcc()

Checks if job execution has been temporarily held (suspended).

If job has completed its execution, then false is always returned.

Returns:

True if job has been held.

holdcc

@Nullable
<T> T holdcc()

Holds (suspends) a given job indefinitely until callcc() is called. Job will remain in active queue, but its heldcc() method will return true. Implementations of CollisionSpi should check if jobs are held or not as needed.

All jobs should stop their execution and return right after calling 'holdcc(..)' method. For convenience, this method always returns null, so you can hold and return in one line by calling 'return holdcc()' method.

If job is not running or has completed its execution, then no-op.

The 'cc' suffix stands for 'current-continuation' which is a pretty standard notation for this concept that originated from Scheme programming language. Basically, the job is held to be continued later, hence the name of the method.

Type Parameters:

T - Type of the job execution result.

Returns:

Always returns null for convenience to be used in code with return statement.

Throws:

IllegalStateException - If job has been already held before.

holdcc

@Nullable
<T> T holdcc(long timeout)

Holds (suspends) a given job for specified timeout or until callcc() is called. Holds (suspends) a given job for specified timeout or until callcc() is called. Job will remain in active queue, but its heldcc() method will return true. Implementations of CollisionSpi should check if jobs are held or not as needed.

All jobs should stop their execution and return right after calling 'holdcc(..)' method. For convenience, this method always returns null, so you can hold and return in one line by calling 'return holdcc()'.

If job is not running or has completed its execution, then no-op.

The 'cc' suffix stands for 'current-continuation' which is a fairly standard notation for this concept. Basically, the job is held to be continued later, hence the name of the method.

Type Parameters:

T - Type of the job execution result.

Parameters:

timeout - Timeout in milliseconds after which job will be automatically resumed.

Returns:

Always returns null for convenience to be used in code with return statement.

Throws:

IllegalStateException - If job has been already held before

callcc

void callcc()

Resumes job if it was held by holdcc() method. Resuming job means that ComputeJob.execute() method will be called again. It is user's responsibility to check, as needed, whether job is executing from scratch and has been resumed.

Note that the job is resumed with exactly the same state as of when it was 'held' via the holdcc() method.

If job is not running, has not been suspended, or has completed its execution, then no-op.

The method is named after 'call-with-current-continuation' design pattern, commonly abbreviated as 'call/cc', which originated in Scheme programming language.