Class PipedReader
java.lang.Object
com.northconcepts.datapipeline.core.DataObject
com.northconcepts.datapipeline.core.Endpoint
com.northconcepts.datapipeline.core.DataEndpoint
com.northconcepts.datapipeline.core.DataReader
com.northconcepts.datapipeline.core.PipedReader
Reads the records written to a connected
PipedWriter, usually on another thread; reads block until a record arrives
and the stream ends when the writer is closed.-
Nested Class Summary
Nested classes/interfaces inherited from class com.northconcepts.datapipeline.core.DataEndpoint
DataEndpoint.State -
Field Summary
Fields inherited from class com.northconcepts.datapipeline.core.DataReader
fieldLineage, recordLineageFields inherited from class com.northconcepts.datapipeline.core.DataEndpoint
lastRecord, PRODUCT, PRODUCT_VERSION, VENDOR, XML_INPUT_FACTORY_KEYFields inherited from class com.northconcepts.datapipeline.core.Endpoint
BUFFER_SIZE, captureElapsedTime, DEFAULT_READ_BUFFER_SIZEFields inherited from class com.northconcepts.datapipeline.core.DataObject
id, log, name, TIMESTAMP_FORMAT -
Constructor Summary
ConstructorsConstructorDescriptionCreates a reader with an unbounded queue.PipedReader(int queueCapacity) Creates a reader whose queue holds at mostqueueCapacityrecords; the writer blocks while it is full. -
Method Summary
Modifier and TypeMethodDescriptionaddExceptionProperties(DataException exception) Adds this endpoint's current state to aDataException.intReturns the number of records that can probably be read without blocking.getQueue()Returns the queue shared with the connectedPipedWriter.protected RecordreadImpl()Overridden by subclasses to read the next record from thisDataReader.Methods inherited from class com.northconcepts.datapipeline.core.DataReader
addLineage, getBufferSize, getNestedEndpoint, getNestedReader, getReader, getRootEndpoint, getRootReader, isExhausted, isLineageSupported, isSaveLineage, peek, pop, push, read, setSaveLineage, skipMethods inherited from class com.northconcepts.datapipeline.core.DataEndpoint
close, decrementRecordCount, enableJmx, getLastRecord, getRecordCount, getRecordCountAsBigInteger, getRecordCountAsString, incrementRecordCount, isRecordCountBigInteger, open, resetRecordCount, toStringMethods inherited from class com.northconcepts.datapipeline.core.Endpoint
addElapsedtime, assertClosed, assertNotOpened, assertOpened, finalize, getClosedOn, getDescription, getElapsedTime, getElapsedTimeAsString, getOpenedOn, getOpenElapsedTime, getOpenElapsedTimeAsString, getSelfTime, getSelfTimeAsString, getState, isCaptureElapsedTime, isClosed, isOpen, setCaptureElapsedTime, setDescription
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Constructor Details
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PipedReader
public PipedReader()Creates a reader with an unbounded queue. -
PipedReader
public PipedReader(int queueCapacity) Creates a reader whose queue holds at mostqueueCapacityrecords; the writer blocks while it is full.
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Method Details
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getQueue
Returns the queue shared with the connectedPipedWriter. -
available
Description copied from class:DataReaderReturns the number of records that can probably be read without blocking.- Overrides:
availablein classDataReader- Throws:
DataException
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readImpl
Description copied from class:DataReaderOverridden by subclasses to read the next record from thisDataReader. The default implementation ofDataReader.read()now insures that this method will not be called again after it returns anull.If no record is available,
nullwill be returned.Contract for subclasses (see also
docs/authoring/DataReader.md):- Return
nullexactly once to signal end-of-stream. - Do not call this method directly —
DataReader.read()is the template method that wraps exceptions, increments the record count, and tracks lineage. - Do not call
DataEndpoint.incrementRecordCount()here;DataReader.read()already does. - Throw raw exceptions;
DataReader.read()wraps them viaexception(throwable).
- Specified by:
readImplin classDataReader- Throws:
Throwable
- Return
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addExceptionProperties
Description copied from class:EndpointAdds this endpoint's current state to aDataException. Since this method is called whenever an exception is thrown, subclasses should override it to add their specific information.- Overrides:
addExceptionPropertiesin classDataReader
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