Class DatasetReader
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.foundations.pipeline.dataset.DatasetReader
Obtains records from those cached in a
Dataset.-
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
ConstructorsConstructorDescriptionDatasetReader(Dataset dataset) Creates a reader for all the dataset's records; reads wait for records it is still loading.DatasetReader(Dataset dataset, long offset, int count) Creates a reader for up tocountrecords starting at the 0-basedoffset(0 or less reads to the end). -
Method Summary
Methods inherited from class com.northconcepts.datapipeline.core.DataReader
addExceptionProperties, addLineage, available, 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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DatasetReader
Creates a reader for up tocountrecords starting at the 0-basedoffset(0 or less reads to the end). Reads wait for records the dataset is still loading. -
DatasetReader
Creates a reader for all the dataset's records; reads wait for records it is still loading.
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Method Details
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getDataset
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getOffset
public long getOffset()Returns the 0-based index of the first record to read. -
getCount
public int getCount()Returns the maximum number of records to read; 0 or less means no limit. -
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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