com.marklogic.client.datamovement

Class ExportToWriterListener

java.lang.Object

com.marklogic.client.datamovement.ExportListener

com.marklogic.client.datamovement.ExportToWriterListener

All Implemented Interfaces:

BatchListener<QueryBatch>, QueryBatchListener

public class ExportToWriterListener
extends ExportListener

An extension of ExportListener which facilitates writing all documents to a single Writer output stream. The Writer could be a FileWriter, for example, to write output to a CSV file. The Writer could pipe to a socket, for example, to send the output directly to another server endpoint.

By default only document contents are retrieved. If you would also like metadata, make sure to call withMetadataCategory to configure which categories of metadata you desire.

As with all the provided listeners, this listener will not meet the needs of all applications but the source code for it should serve as helpful sample code so you can write your own custom listeners.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ExportToWriterListener.OutputListener The listener interface required by onGenerateOutput.

Constructor Summary

Constructors

Constructor and Description
ExportToWriterListener(java.io.Writer writer)

Method Summary

Modifier and Type	Method and Description
void	initializeListener(QueryBatcher queryBatcher) This implementation of initializeListener adds this instance of ExportToWriterListener to the two RetryListener's in this QueryBatcher so they will retry any batches that fail during the read request.
ExportToWriterListener	onGenerateOutput(ExportToWriterListener.OutputListener listener) Registers a custom listener to override the default behavior for each document which sends the document contents to the writer.
void	processEvent(QueryBatch batch) This is the method QueryBatcher calls for ExportListener to do its thing.
ExportToWriterListener	withMetadataCategory(DocumentManager.Metadata category) Adds a metadata category to retrieve with each document.
ExportToWriterListener	withNonDocumentFormat(Format nonDocumentFormat) The format for the metadata retrieved with each document.
ExportToWriterListener	withRecordPrefix(java.lang.String prefix) Sets the string prefix to send to the writer before each record.
ExportToWriterListener	withRecordSuffix(java.lang.String suffix) Sets the string suffix to append to the writer after each record.
ExportToWriterListener	withTransform(ServerTransform transform) Sets the server tranform to modify the document contents.

Methods inherited from class com.marklogic.client.datamovement.ExportListener

getBatchFailureListeners, getDocs, onDocumentPageReady, onDocumentReady, onFailure, withConsistentSnapshot

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ExportToWriterListener

public ExportToWriterListener(java.io.Writer writer)

Method Detail

initializeListener

public void initializeListener(QueryBatcher queryBatcher)

This implementation of initializeListener adds this instance of ExportToWriterListener to the two RetryListener's in this QueryBatcher so they will retry any batches that fail during the read request.

Specified by:

initializeListener in interface QueryBatchListener

Overrides:

initializeListener in class ExportListener

Parameters:

queryBatcher - the QueryBatcher which will call this Listener

processEvent

public void processEvent(QueryBatch batch)

Description copied from class: ExportListener

This is the method QueryBatcher calls for ExportListener to do its thing. You should not need to call it.

Specified by:

processEvent in interface BatchListener<QueryBatch>

Specified by:

processEvent in interface QueryBatchListener

Overrides:

processEvent in class ExportListener

Parameters:

batch - the batch of uris and some metadata about the current status of the job

withRecordSuffix

public ExportToWriterListener withRecordSuffix(java.lang.String suffix)

Sets the string suffix to append to the writer after each record.

Parameters:

suffix - the string suffix

Returns:

this instance (for method chaining)

withRecordPrefix

public ExportToWriterListener withRecordPrefix(java.lang.String prefix)

Sets the string prefix to send to the writer before each record.

Parameters:

prefix - the string prefix

Returns:

this instance (for method chaining)

onGenerateOutput

public ExportToWriterListener onGenerateOutput(ExportToWriterListener.OutputListener listener)

Registers a custom listener to override the default behavior for each document which sends the document contents to the writer. This listener can choose what string to send to the writer for each document.

Parameters:

listener - the custom listener (or lambda expression)

Returns:

this instance (for method chaining)

withTransform

public ExportToWriterListener withTransform(ServerTransform transform)

Description copied from class: ExportListener

Sets the server tranform to modify the document contents.

Overrides:

withTransform in class ExportListener

Parameters:

transform - the name of the transform already installed in the REST server

Returns:

this instance for method chaining

withMetadataCategory

public ExportToWriterListener withMetadataCategory(DocumentManager.Metadata category)

Adds a metadata category to retrieve with each document. The metadata will be available via DocumentRecord.getMetadata in each DocumentRecord sent to the OutputListener registered with onGenerateOutput. To specify the format for the metdata, call withNonDocumentFormat.

Overrides:

withMetadataCategory in class ExportListener

Parameters:

category - the metadata category to retrieve

Returns:

this instance (for method chaining)

See Also:

DocumentManager.setMetadataCategories

withNonDocumentFormat

public ExportToWriterListener withNonDocumentFormat(Format nonDocumentFormat)

The format for the metadata retrieved with each document. The metadata will be available in each DocumentRecord sent to the OutputListener registered with onGenerateOutput.

Overrides:

withNonDocumentFormat in class ExportListener

Parameters:

nonDocumentFormat - the format for the metadata

Returns:

this instance (for method chaining)

See Also:

DocumentManager.setNonDocumentFormat