Package se.liu.ida.hefquin.engine.queryplan.executable.impl.pullbased

Class PullBasedExecPlanTaskBase

java.lang.Object

se.liu.ida.hefquin.engine.queryplan.executable.impl.ExecPlanTaskBase

se.liu.ida.hefquin.engine.queryplan.executable.impl.pullbased.PullBasedExecPlanTaskBase

All Implemented Interfaces:

Runnable, StatsProvider, ExecPlanTask

Direct Known Subclasses:

PullBasedExecPlanTaskForBinaryOperator, PullBasedExecPlanTaskForNullaryOperator, PullBasedExecPlanTaskForUnaryOperator

public abstract class PullBasedExecPlanTaskBase
extends ExecPlanTaskBase

Pull-based implementation of ExecPlanTask. This implementation makes several assumptions: 1) There is only one thread that consumes the output of this task (by calling getNextIntermediateResultBlock()). 2) If a task consumes the output of another task as input, then that other task must already be running before the consuming task is started.

Nested Class Summary

Nested classes/interfaces inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ExecPlanTaskBase

ExecPlanTaskBase.ExecPlanTaskStatsImpl, ExecPlanTaskBase.Status

Field Summary

Fields inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ExecPlanTaskBase

availableResultBlocks, execCxt, preferredMinimumBlockSize

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PullBasedExecPlanTaskBase(ExecutionContext execCxt, int preferredMinimumBlockSize)

Method Summary

Modifier and Type	Method	Description
final IntermediateResultBlock	getNextIntermediateResultBlock()	Returns either the next intermediate result block produced by this task or null if all these blocks have been returned already to earlier calls of this function.
protected abstract IntermediateResultBlock	produceNextIntermediateResultBlock()	Produces and returns a new IntermediateResultBlock.
final void	run()

Methods inherited from class se.liu.ida.hefquin.engine.queryplan.executable.impl.ExecPlanTaskBase

getCauseOfFailure, getExceptionsCaughtDuringExecution, getExecOp, getStats, getStatus, hasFailed, hasNextIntermediateResultBlockAvailable, isCompleted, isRunning, resetStats, setCauseOfFailure, setStatus

Methods inherited from class java.lang.Object

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

Constructor Details

PullBasedExecPlanTaskBase

protected PullBasedExecPlanTaskBase(ExecutionContext execCxt,
 int preferredMinimumBlockSize)

Method Details

run

public final void run()

produceNextIntermediateResultBlock

protected abstract IntermediateResultBlock produceNextIntermediateResultBlock()
                                                                       throws ExecOpExecutionException,
ExecPlanTaskInputException,
ExecPlanTaskInterruptionException

Produces and returns a new IntermediateResultBlock. Unless this is the very last block that can be produced, the block must contain at least ExecPlanTaskBase.preferredMinimumBlockSize solution mappings. To indicate that the returned block is the last one that can be produced the method may either return a block with fewer than ExecPlanTaskBase.preferredMinimumBlockSize solution mappings or return a block of type LastIntermediateResultBlock.

Throws:

ExecOpExecutionException

ExecPlanTaskInputException

ExecPlanTaskInterruptionException

getNextIntermediateResultBlock

public final IntermediateResultBlock getNextIntermediateResultBlock()
                                                             throws ExecPlanTaskInterruptionException,
ExecPlanTaskInputException

Description copied from interface: ExecPlanTask

Returns either the next intermediate result block produced by this task or null if all these blocks have been returned already to earlier calls of this function. If no next block is currently available at the time when this function is called, then the call of this function causes the calling thread to wait until the next block has been produced (or it has become clear that no more blocks can be produced anymore).

Throws:

ExecPlanTaskInterruptionException

ExecPlanTaskInputException