org.apache.lucene.codecs

Class TermVectorsWriter

java.lang.Object

org.apache.lucene.codecs.TermVectorsWriter

All Implemented Interfaces:

Closeable, AutoCloseable, Accountable

Direct Known Subclasses:

CompressingTermVectorsWriter

public abstract class TermVectorsWriter
extends Object
implements Closeable, Accountable

Codec API for writing term vectors:

1. For every document, startDocument(int) is called, informing the Codec how many fields will be written.
2. startField(FieldInfo, int, boolean, boolean, boolean) is called for each field in the document, informing the codec how many terms will be written for that field, and whether or not positions, offsets, or payloads are enabled.
3. Within each field, startTerm(BytesRef, int) is called for each term.
4. If offsets and/or positions are enabled, then addPosition(int, int, int, BytesRef) will be called for each term occurrence.
5. After all documents have been written, finish(FieldInfos, int) is called for verification/sanity-checks.
6. Finally the writer is closed (close())

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

Field Summary

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TermVectorsWriter() Sole constructor.

Method Summary

Modifier and Type	Method and Description
protected void	addAllDocVectors(Fields vectors, MergeState mergeState) Safe (but, slowish) default method to write every vector field in the document.
abstract void	addPosition(int position, int startOffset, int endOffset, BytesRef payload) Adds a term position and offsets
void	addProx(int numProx, DataInput positions, DataInput offsets) Called by IndexWriter when writing new segments.
abstract void	close()
abstract void	finish(FieldInfos fis, int numDocs) Called before close(), passing in the number of documents that were written.
void	finishDocument() Called after a doc and all its fields have been added.
void	finishField() Called after a field and all its terms have been added.
void	finishTerm() Called after a term and all its positions have been added.
int	merge(MergeState mergeState) Merges in the term vectors from the readers in mergeState.
abstract void	startDocument(int numVectorFields) Called before writing the term vectors of the document.
abstract void	startField(FieldInfo info, int numTerms, boolean positions, boolean offsets, boolean payloads) Called before writing the terms of the field.
abstract void	startTerm(BytesRef term, int freq) Adds a term and its term frequency freq.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources, ramBytesUsed

Constructor Detail

TermVectorsWriter

protected TermVectorsWriter()

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

Method Detail

startDocument

public abstract void startDocument(int numVectorFields)
                            throws IOException

Called before writing the term vectors of the document. startField(FieldInfo, int, boolean, boolean, boolean) will be called numVectorFields times. Note that if term vectors are enabled, this is called even if the document has no vector fields, in this case numVectorFields will be zero.

Throws:

IOException

finishDocument

public void finishDocument()
                    throws IOException

Called after a doc and all its fields have been added.

Throws:

IOException

startField

public abstract void startField(FieldInfo info,
                                int numTerms,
                                boolean positions,
                                boolean offsets,
                                boolean payloads)
                         throws IOException

Called before writing the terms of the field. startTerm(BytesRef, int) will be called numTerms times.

Throws:

IOException

finishField

public void finishField()
                 throws IOException

Called after a field and all its terms have been added.

Throws:

IOException

startTerm

public abstract void startTerm(BytesRef term,
                               int freq)
                        throws IOException

Adds a term and its term frequency freq. If this field has positions and/or offsets enabled, then addPosition(int, int, int, BytesRef) will be called freq times respectively.

Throws:

IOException

finishTerm

public void finishTerm()
                throws IOException

Called after a term and all its positions have been added.

Throws:

IOException

addPosition

public abstract void addPosition(int position,
                                 int startOffset,
                                 int endOffset,
                                 BytesRef payload)
                          throws IOException

Adds a term position and offsets

Throws:

IOException

finish

public abstract void finish(FieldInfos fis,
                            int numDocs)
                     throws IOException

Called before close(), passing in the number of documents that were written. Note that this is intentionally redundant (equivalent to the number of calls to startDocument(int), but a Codec should check that this is the case to detect the JRE bug described in LUCENE-1282.

Throws:

IOException

addProx

public void addProx(int numProx,
                    DataInput positions,
                    DataInput offsets)
             throws IOException

Called by IndexWriter when writing new segments.

This is an expert API that allows the codec to consume positions and offsets directly from the indexer.

The default implementation calls addPosition(int, int, int, BytesRef), but subclasses can override this if they want to efficiently write all the positions, then all the offsets, for example.

NOTE: This API is extremely expert and subject to change or removal!!!

Throws:

IOException

NOTE: This API is for internal purposes only and might change in incompatible ways in the next release.

merge

public int merge(MergeState mergeState)
          throws IOException

Merges in the term vectors from the readers in mergeState. The default implementation skips over deleted documents, and uses startDocument(int), startField(FieldInfo, int, boolean, boolean, boolean), startTerm(BytesRef, int), addPosition(int, int, int, BytesRef), and finish(FieldInfos, int), returning the number of documents that were written. Implementations can override this method for more sophisticated merging (bulk-byte copying, etc).

Throws:

IOException

addAllDocVectors

protected final void addAllDocVectors(Fields vectors,
                                      MergeState mergeState)
                               throws IOException

Safe (but, slowish) default method to write every vector field in the document.

Throws:

IOException

close

public abstract void close()
                    throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException