org.apache.lucene.codecs

Class FieldsConsumer

java.lang.Object

org.apache.lucene.codecs.FieldsConsumer

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

Direct Known Subclasses:

BlockTreeTermsWriter, PerFieldPostingsFormat.FieldsWriter, VersionBlockTreeTermsWriter

public abstract class FieldsConsumer
extends java.lang.Object
implements java.io.Closeable

Abstract API that consumes terms, doc, freq, prox, offset and payloads postings. Concrete implementations of this actually do "something" with the postings (write it into the index in a specific format).

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FieldsConsumer() Sole constructor.

Method Summary

Modifier and Type	Method and Description
abstract void	close()
void	merge(MergeState mergeState, NormsProducer norms) Merges in the fields from the readers in mergeState.
abstract void	write(Fields fields, NormsProducer norms) Write all fields, terms and postings.

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldsConsumer

protected FieldsConsumer()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

write

public abstract void write(Fields fields,
                           NormsProducer norms)
                    throws java.io.IOException

Write all fields, terms and postings. This the "pull" API, allowing you to iterate more than once over the postings, somewhat analogous to using a DOM API to traverse an XML tree.

Notes:

• You must compute index statistics, including each Term's docFreq and totalTermFreq, as well as the summary sumTotalTermFreq, sumTotalDocFreq and docCount.
• You must skip terms that have no docs and fields that have no terms, even though the provided Fields API will expose them; this typically requires lazily writing the field or term until you've actually seen the first term or document.
• The provided Fields instance is limited: you cannot call any methods that return statistics/counts; you cannot pass a non-null live docs when pulling docs/positions enums.

Throws:

java.io.IOException

merge

public void merge(MergeState mergeState,
                  NormsProducer norms)
           throws java.io.IOException

Merges in the fields from the readers in mergeState. The default implementation skips and maps around deleted documents, and calls write(Fields,NormsProducer). Implementations can override this method for more sophisticated merging (bulk-byte copying, etc).

Throws:

java.io.IOException

close

public abstract void close()
                    throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException