com.pervasive.datarush.operators

Interface MetadataCalculationContext

All Superinterfaces:

MetadataContext

All Known Subinterfaces:

IterativeMetadataContext, StreamingMetadataContext

public interface MetadataCalculationContext
extends MetadataContext

Base interface for all contexts in which metadata is being computed.

Method Summary

Modifier and Type	Method and Description
CompilationLevel	getCompilationLevel() Returns the compilation level with which the graph is being compiled
LogicalOperator	getOperator() Returns the operator bound to this context.
void	setOutputMetadata(LogicalPort logicalPort, PortMetadata metadata) Sets the metadata associated with the given output port
void	setOutputMetadataDynamic(AbstractModelPort<?> port, boolean dynamic) Indicates that the metadata for the given output port is dynamic.
void	setRequiredMetadata(LogicalPort logicalPort, PortMetadata metadata) Sets the required metadata for the given input.
void	setStagingForced(LogicalPort inputPort, boolean forced) Can be used to force staging (writing to disk) of input data.

Methods inherited from interface com.pervasive.datarush.operators.MetadataContext

getCombinedMetadata, getEngineConfig, getFileClient, getMaxParallelism, getPath, getRequiredMetadata, getSourceMaxParallelism, getSourceMetadata, isParallel, isSourceConnected, isSourceParallel

Method Detail

getCompilationLevel

CompilationLevel getCompilationLevel()

Returns the compilation level with which the graph is being compiled

Returns:

the compilation level

getOperator

LogicalOperator getOperator()

Returns the operator bound to this context. Typically operators code does not need this method; instead it is used by various MetadataUtil methods for convenience.

Returns:

the operator bound to this context.

setOutputMetadata

void setOutputMetadata(LogicalPort logicalPort,
                       PortMetadata metadata)

Sets the metadata associated with the given output port

Parameters:

logicalPort - the output port

metadata - the output metadata

setRequiredMetadata

void setRequiredMetadata(LogicalPort logicalPort,
                         PortMetadata metadata)

Sets the required metadata for the given input. Note that operators should generally not call this method directly. Rather they should use one of the type-safe/convenience methods on the various subclasses of LogicalPort. For example:

    //set the required data ordering for the "input" record port
    input.setRequiredDataOrdering(ctx,ordering)
 

Parameters:

logicalPort - the input port

metadata - the required metadata

setStagingForced

void setStagingForced(LogicalPort inputPort,
                      boolean forced)

Can be used to force staging (writing to disk) of input data. Normally input data is streamed from source operator to target operator if possible. In certain scenarios, this can result in dataflow deadlock. The framework automatically handles these scenarios by dynamically writing data to disk as needed in order to alleviate deadlock. This flag can be used those scenarios since staging can be handled much more efficiently if it is declared up-front rather than discovered at runtime.

Parameters:

inputPort - must be an input port

forced - whether to force staging

setOutputMetadataDynamic

void setOutputMetadataDynamic(AbstractModelPort<?> port,
                              boolean dynamic)

Indicates that the metadata for the given output port is dynamic. If metadata is dynamic, outputMetadata must not be specified. The graph is compiled and executed up until this operator. Following execution of this operator, downstream operators can then be compiled. Note that dynamic metadata should be used sparingly as it causes graph compilation errors to be postponed until after a (potentially) long operation.

Parameters:

port - the output port

dynamic - a value of true means metadata is dynamic.