io.prestosql.operator

Interface Operator

All Superinterfaces:

AutoCloseable

All Known Subinterfaces:

SourceOperator

All Known Implementing Classes:

AggregationOperator, AssignUniqueIdOperator, DeleteOperator, DevNullOperator, DistinctLimitOperator, EnforceSingleRowOperator, ExchangeOperator, ExplainAnalyzeOperator, FilterAndProjectOperator, FinishedOperator, GroupIdOperator, HashAggregationOperator, HashBuilderOperator, HashSemiJoinOperator, IndexSourceOperator, LimitOperator, LocalExchangeSinkOperator, LocalExchangeSourceOperator, LocalMergeSourceOperator, LookupJoinOperator, LookupOuterOperator, MarkDistinctOperator, MergeOperator, MetadataDeleteOperator, NestedLoopBuildOperator, NestedLoopJoinOperator, NullOutputOperator, OrderByOperator, PageBufferOperator, PageConsumerOperator, PagesIndexBuilderOperator, PageSourceOperator, PartitionedOutputOperator, RowNumberOperator, ScanFilterAndProjectOperator, SetBuilderOperator, SpatialIndexBuilderOperator, SpatialJoinOperator, StatisticsWriterOperator, StreamingAggregationOperator, TableFinishOperator, TableScanOperator, TableWriterOperator, TaskOutputOperator, TopNOperator, TopNRowNumberOperator, UnnestOperator, ValuesOperator, WindowOperator, WorkProcessorPipelineSourceOperator

public interface Operator
extends AutoCloseable

Field Summary

Fields

Modifier and Type	Field and Description
static com.google.common.util.concurrent.ListenableFuture<?>	NOT_BLOCKED

Method Summary

Modifier and Type	Method and Description
void	addInput(Page page) Adds an input page to the operator.
default void	close() This method will always be called before releasing the Operator reference.
void	finish() Notifies the operator that no more pages will be added and the operator should finish processing and flush results.
default void	finishMemoryRevoke() Clean up and release resources after completed memory revoking.
OperatorContext	getOperatorContext()
Page	getOutput() Gets an output page from the operator.
default com.google.common.util.concurrent.ListenableFuture<?>	isBlocked() Returns a future that will be completed when the operator becomes unblocked.
boolean	isFinished() Is this operator completely finished processing and no more output pages will be produced.
boolean	needsInput() Returns true if and only if this operator can accept an input page.
default com.google.common.util.concurrent.ListenableFuture<?>	startMemoryRevoke() After calling this method operator should revoke all reserved revocable memory.

Field Detail

NOT_BLOCKED

static final com.google.common.util.concurrent.ListenableFuture<?> NOT_BLOCKED

Method Detail

getOperatorContext

OperatorContext getOperatorContext()

isBlocked

default com.google.common.util.concurrent.ListenableFuture<?> isBlocked()

Returns a future that will be completed when the operator becomes unblocked. If the operator is not blocked, this method should return NOT_BLOCKED.

needsInput

boolean needsInput()

Returns true if and only if this operator can accept an input page.

addInput

void addInput(Page page)

Adds an input page to the operator. This method will only be called if needsInput() returns true.

getOutput

Page getOutput()

Gets an output page from the operator. If no output data is currently available, return null.

startMemoryRevoke

default com.google.common.util.concurrent.ListenableFuture<?> startMemoryRevoke()

After calling this method operator should revoke all reserved revocable memory. As soon as memory is revoked returned future should be marked as done.

Spawned threads can not modify OperatorContext because it's not thread safe. For this purpose implement finishMemoryRevoke()

Since memory revoking signal is delivered asynchronously to the Operator, implementation must gracefully handle the case when there no longer is any revocable memory allocated.

After this method is called on Operator the Driver is disallowed to call any processing methods on it (isBlocked/needsInput/addInput/getOutput) until finishMemoryRevoke() is called.

finishMemoryRevoke

default void finishMemoryRevoke()

Clean up and release resources after completed memory revoking. Called by driver once future returned by startMemoryRevoke is completed.

finish

void finish()

Notifies the operator that no more pages will be added and the operator should finish processing and flush results. This method will not be called if the Task is already failed or canceled.

isFinished

boolean isFinished()

Is this operator completely finished processing and no more output pages will be produced.

close

default void close()
            throws Exception

This method will always be called before releasing the Operator reference.

Specified by:

close in interface AutoCloseable

Throws:

Exception