- java.lang.Object
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- com.pervasive.datarush.operators.AbstractLogicalOperator
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- com.pervasive.datarush.operators.StreamingOperator
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- com.pervasive.datarush.operators.ExecutableOperator
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- com.pervasive.datarush.operators.io.WriteSink
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- All Implemented Interfaces:
LogicalOperator
,RecordSinkOperator
,SinkOperator<RecordPort>
public final class WriteSink extends ExecutableOperator implements RecordSinkOperator
Writes a stream of records to a data sink. The sink accepts a sequence of bytes which represent formatted records, identical in logical structure. The mapping between physical and logical structure is encapsulated in a format descriptor which must be provided.This operator is low-level, providing a generalized model for reading files in a distributed fashion. Typically,
WriteSink
is not directly used in a graph, instead being indirectly used though a composite operator such as one derived fromAbstractWriter
providing a more appropriate interface to the end user.Parallelized writes are supported by creating multiple output sinks from the original target, called fragments, each representing the portion of data on one partition. In the case of a write to as file system, this would result in a directory of files. To write in parallel, the target must support the concept of fragmenting. If a target does not, the write is forced to be non-parallel.
A port is provided which signals completion of the writer. This can be used to express a dependency between operators based on the target having been successfully written.
The writer makes a best-effort attempt to validate the target before execution, but cannot always guarantee correctness, depending on the nature of the target. This is done to try to prevent misconfigured graphs from executing where the writer may not execute until a late phase when a failure may result in the loss of a significant amount of work being lost.
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Constructor Summary
Constructors Constructor Description WriteSink()
Writes an empty target with default settings.WriteSink(boolean includeDoneSignal)
Writes an empty target with default settings.WriteSink(ByteSink target, DataFormat format)
Reads the specified target using the given format.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected ExecutableOperator
cloneForExecution()
Performs a deep copy of the operator for execution.protected void
computeMetadata(StreamingMetadataContext ctx)
Implementations must adhere to the following contractsprotected void
execute(ExecutionContext ctx)
Executes the operator.DataFormat
getFormat()
Gets the data format for the configured target.FormattingOptions
getFormatOptions()
Gets the formatting options used by the writer.boolean
getIncludeDoneSignal()
Gets the property value for the include done signal setting.RecordPort
getInput()
Gets the record port providing the records to write to the target sink.WriteMode
getMode()
Gets how existing files should be handled by the writer.ByteSink
getTarget()
Gets the target sink for the reader.boolean
getWriteOnClient()
Indicates whether the writer should write a file on the client.boolean
getWriteSingleSink()
Indicates whether the writer produces a single output file.boolean
isIgnoreSortOrder()
If set to true, the writer will write in any order.void
setFormat(DataFormat format)
Sets the data format for the configured target.void
setFormatOptions(FormattingOptions options)
Sets the formatting options used by the writer.void
setIgnoreSortOrder(boolean ignoreSortOrder)
If set to true, the writer will write in any order.void
setMode(WriteMode mode)
Sets how the writer should handle an existing target.void
setTarget(ByteSink target)
Sets the target sink for the reader.void
setWriteOnClient(boolean writeOnClient)
Set whether the writer should write a file on the local client.void
setWriteSingleSink(boolean enabled)
Set whether the writer should produce a single output file or multiple ones.-
Methods inherited from class com.pervasive.datarush.operators.ExecutableOperator
getNumInputCopies, getPortSettings, handleInactiveOutput
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Methods inherited from class com.pervasive.datarush.operators.AbstractLogicalOperator
disableParallelism, getInputPorts, getOutputPorts, newInput, newInput, newOutput, newRecordInput, newRecordInput, newRecordOutput, notifyError
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface com.pervasive.datarush.operators.LogicalOperator
disableParallelism, getInputPorts, getOutputPorts
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Constructor Detail
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WriteSink
public WriteSink()
Writes an empty target with default settings. Both the target and format must be set before execution or an error will be raised.- See Also:
setTarget(ByteSink)
,setFormat(DataFormat)
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WriteSink
public WriteSink(boolean includeDoneSignal)
Writes an empty target with default settings. Both the target and format must be set before execution or an error will be raised.- See Also:
setTarget(ByteSink)
,setFormat(DataFormat)
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WriteSink
public WriteSink(ByteSink target, DataFormat format)
Reads the specified target using the given format. Default options are used.- Parameters:
target
- the target to writeformat
- the target data format
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Method Detail
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getInput
public RecordPort getInput()
Gets the record port providing the records to write to the target sink.- Specified by:
getInput
in interfaceRecordSinkOperator
- Specified by:
getInput
in interfaceSinkOperator<RecordPort>
- Returns:
- the input port for records to write
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getIncludeDoneSignal
public boolean getIncludeDoneSignal()
Gets the property value for the include done signal setting.- Returns:
- true if enabled; false by default
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getFormat
public DataFormat getFormat()
Gets the data format for the configured target.- Returns:
- the data format
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setFormat
public void setFormat(DataFormat format)
Sets the data format for the configured target.- Parameters:
format
- the target data format
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getTarget
public ByteSink getTarget()
Gets the target sink for the reader.- Returns:
- the write target
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setTarget
public void setTarget(ByteSink target)
Sets the target sink for the reader.- Parameters:
target
- the target to write
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getFormatOptions
public FormattingOptions getFormatOptions()
Gets the formatting options used by the writer.- Returns:
- the format options
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setFormatOptions
public void setFormatOptions(FormattingOptions options)
Sets the formatting options used by the writer.- Parameters:
options
- the format options to use- See Also:
DataFormat.DataFormatter
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getMode
public WriteMode getMode()
Gets how existing files should be handled by the writer.- Returns:
- the configured behavior with respect to target files
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setMode
public void setMode(WriteMode mode)
Sets how the writer should handle an existing target.- Parameters:
mode
- the behavior to use for existing files
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getWriteSingleSink
public boolean getWriteSingleSink()
Indicates whether the writer produces a single output file.- Returns:
true
if the writer should write a single output,false
otherwise.
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setWriteSingleSink
public void setWriteSingleSink(boolean enabled)
Set whether the writer should produce a single output file or multiple ones. By default, an output file will be produced for each partition, if the target sink supports this.- Parameters:
enabled
- indicates whether a single output file should be written
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getWriteOnClient
public boolean getWriteOnClient()
Indicates whether the writer should write a file on the client. This also disables the parallelism on the sink.- Returns:
true
if the writer should a file on the client,false
otherwise.
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setWriteOnClient
public void setWriteOnClient(boolean writeOnClient)
Set whether the writer should write a file on the local client. This has the effect of disabling the parallelism on the sink.- Parameters:
writeOnClient
- indicates whether the writer should write a file on the client.
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isIgnoreSortOrder
public boolean isIgnoreSortOrder()
If set to true, the writer will write in any order. If false, the writer will preserve the current sorted state of the input.- Returns:
- whether to ignore sort order.
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setIgnoreSortOrder
public void setIgnoreSortOrder(boolean ignoreSortOrder)
If set to true, the writer will write in any order. If false, the writer will preserve the current sorted state of the input.- Parameters:
ignoreSortOrder
- whether to ignore sort order.
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computeMetadata
protected void computeMetadata(StreamingMetadataContext ctx)
Description copied from class:StreamingOperator
Implementations must adhere to the following contractsGeneral
Regardless of input ports/output port types, all implementations must do the following:- Validation. Validation of configuration should always be performed first.
- Declare parallelizability.. Implementations must declare parallelizability by calling
StreamingMetadataContext.parallelize(ParallelismStrategy)
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Input record ports
Implementations with input record ports must declare the following:- Required data ordering: Implementations that have data ordering requirements must declare them by calling
- Required data distribution (only applies to parallelizable operators): Implementations that have data distribution requirements must declare them by calling
RecordPort#setRequiredDataOrdering
, otherwise data may arrive in any order.RecordPort#setRequiredDataDistribution
, otherwise data will arrive in anunspecified partial distribution
.RecordPort#getSourceDataDistribution
andRecordPort#getSourceDataOrdering
. These should be viewed as a hints to help chose a more efficient algorithm. In such cases, though, operators must still declare data ordering and data distribution requirements; otherwise there is no guarantee that data will arrive sorted/distributed as required.Output record ports
Implementations with output record ports must declare the following:- Type: Implementations must declare their output type by calling
RecordPort#setType
.
- Output data ordering: Implementations that can make guarantees as to their output
ordering may do so by calling
RecordPort#setOutputDataOrdering
- Output data distribution (only applies to parallelizable operators): Implementations that can make guarantees as to their output
distribution may do so by calling
RecordPort#setOutputDataDistribution
Input model ports
In general, there is nothing special to declare for input model ports. Models are implicitly duplicated to all partitions when going from non-parallel to parallel operators. The case of a model going from a parallel to a non-parallel node is a special case of a "model reducer" operator. In the case of a model reducer, the downstream operator, must declare the following:- Merge handler: Model reducers must declare a merge handler by
calling
AbstractModelPort#setMergeHandler
.
MergeModel
is a convenient, re-usable model reducer, parameterized with a merge-handler.Output model ports
SimpleModelPort
's have no associated metadata and therefore there is never any output metadata to declare.PMMLPort
's, on the other hand, do have associated metadata. For all PMMLPorts, implementations must declare the following:- pmmlModelSpec: Implementations must declare the PMML model spec
by calling
PMMLPort.setPMMLModelSpec
.
- Specified by:
computeMetadata
in classStreamingOperator
- Parameters:
ctx
- the context
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execute
protected void execute(ExecutionContext ctx)
Description copied from class:ExecutableOperator
Executes the operator. Implementations should adhere to the following contracts:- Following execution, all input ports must be at end-of-data.
- Following execution, all output ports must be at end-of-data.
- Specified by:
execute
in classExecutableOperator
- Parameters:
ctx
- context in which to lookup physical ports bound to logical ports
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cloneForExecution
protected ExecutableOperator cloneForExecution()
Description copied from class:ExecutableOperator
Performs a deep copy of the operator for execution. The default implementation is implemented in terms of JSON serialization: we perform a JSON serialization followed by a JSON deserialization. As a best-practice, operator implementations should not override this method. If they must override, though, then they must guarantee that cloneForExecution copies any instance variables that are modified by execute.- Overrides:
cloneForExecution
in classExecutableOperator
- Returns:
- a deep copy of this operator
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