Package org.apache.lucene.codecs

Class PostingsWriterBase

java.lang.Object

org.apache.lucene.codecs.PostingsWriterBase

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

PushPostingsWriterBase

public abstract class PostingsWriterBase
extends Object
implements Closeable

Class that plugs into term dictionaries, such as BlockTreeTermsWriter, and handles writing postings.

See Also:

PostingsReaderBase

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PostingsWriterBase()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
abstract void	close()
abstract void	encodeTerm(long[] longs, DataOutput out, FieldInfo fieldInfo, BlockTermState state, boolean absolute)	Encode metadata as long[] and byte[].
abstract void	init(IndexOutput termsOut, SegmentWriteState state)	Called once after startup, before any terms have been added.
abstract int	setField(FieldInfo fieldInfo)	Sets the current field for writing, and returns the fixed length of long[] metadata (which is fixed per field), called when the writing switches to another field.
abstract BlockTermState	writeTerm(BytesRef term, TermsEnum termsEnum, FixedBitSet docsSeen)	Write all postings for one term; use the provided TermsEnum to pull a PostingsEnum.

Methods inherited from class java.lang.Object

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

Constructor Detail

PostingsWriterBase

protected PostingsWriterBase()

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

Method Detail

init

public abstract void init(IndexOutput termsOut,
                          SegmentWriteState state)
                   throws IOException

Called once after startup, before any terms have been added. Implementations typically write a header to the provided termsOut.

Throws:

IOException

writeTerm

public abstract BlockTermState writeTerm(BytesRef term,
                                         TermsEnum termsEnum,
                                         FixedBitSet docsSeen)
                                  throws IOException

Write all postings for one term; use the provided TermsEnum to pull a PostingsEnum. This method should not re-position the TermsEnum! It is already positioned on the term that should be written. This method must set the bit in the provided FixedBitSet for every docID written. If no docs were written, this method should return null, and the terms dict will skip the term.

Throws:

IOException

encodeTerm

public abstract void encodeTerm(long[] longs,
                                DataOutput out,
                                FieldInfo fieldInfo,
                                BlockTermState state,
                                boolean absolute)
                         throws IOException

Encode metadata as long[] and byte[]. absolute controls whether current term is delta encoded according to latest term. Usually elements in longs are file pointers, so each one always increases when a new term is consumed. out is used to write generic bytes, which are not monotonic. NOTE: sometimes long[] might contain "don't care" values that are unused, e.g. the pointer to postings list may not be defined for some terms but is defined for others, if it is designed to inline some postings data in term dictionary. In this case, the postings writer should always use the last value, so that each element in metadata long[] remains monotonic.

Throws:

IOException

setField

public abstract int setField(FieldInfo fieldInfo)

Sets the current field for writing, and returns the fixed length of long[] metadata (which is fixed per field), called when the writing switches to another field.

close

public abstract void close()
                    throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException