Package org.apache.lucene.index

Class StoredFieldVisitor

java.lang.Object

org.apache.lucene.index.StoredFieldVisitor

Direct Known Subclasses:

DocumentStoredFieldVisitor, StoredFieldsWriter.MergeVisitor

public abstract class StoredFieldVisitor
extends Object

Expert: provides a low-level means of accessing the stored field values in an index. See StoredFields.document(int, StoredFieldVisitor).

NOTE: a StoredFieldVisitor implementation should not try to load or visit other stored documents in the same reader because the implementation of stored fields for most codecs is not reentrant and you will see strange exceptions as a result.

See DocumentStoredFieldVisitor, which is a StoredFieldVisitor that builds the Document containing all stored fields. This is used by StoredFields.document(int).

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

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	StoredFieldVisitor.Status	Enumeration of possible return values for needsField(org.apache.lucene.index.FieldInfo).

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	StoredFieldVisitor()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
void	binaryField(FieldInfo fieldInfo, byte[] value)	Process a binary field.
void	binaryField(FieldInfo fieldInfo, StoredFieldDataInput value)	Expert: Process a binary field directly from the StoredFieldDataInput.
void	doubleField(FieldInfo fieldInfo, double value)	Process a double numeric field.
void	floatField(FieldInfo fieldInfo, float value)	Process a float numeric field.
void	intField(FieldInfo fieldInfo, int value)	Process a int numeric field.
void	longField(FieldInfo fieldInfo, long value)	Process a long numeric field.
abstract StoredFieldVisitor.Status	needsField(FieldInfo fieldInfo)	Hook before processing a field.
void	stringField(FieldInfo fieldInfo, String value)	Process a string field.

Methods inherited from class java.lang.Object

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

Constructor Details

StoredFieldVisitor

protected StoredFieldVisitor()

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

Method Details

binaryField

public void binaryField(FieldInfo fieldInfo,
 StoredFieldDataInput value)
                 throws IOException

Expert: Process a binary field directly from the StoredFieldDataInput. Implementors of this method must read StoredFieldDataInput#length bytes from the given StoredFieldDataInput. The default implementation reads all bytes in a newly created byte array and calls binaryField(FieldInfo, byte[]).

Parameters:

value - the stored field data input.

Throws:

IOException

binaryField

public void binaryField(FieldInfo fieldInfo,
 byte[] value)
                 throws IOException

Process a binary field.

Parameters:

value - newly allocated byte array with the binary contents.

Throws:

IOException

stringField

public void stringField(FieldInfo fieldInfo,
 String value)
                 throws IOException

Process a string field.

Throws:

IOException

intField

public void intField(FieldInfo fieldInfo,
 int value)
              throws IOException

Process a int numeric field.

Throws:

IOException

longField

public void longField(FieldInfo fieldInfo,
 long value)
               throws IOException

Process a long numeric field.

Throws:

IOException

floatField

public void floatField(FieldInfo fieldInfo,
 float value)
                throws IOException

Process a float numeric field.

Throws:

IOException

doubleField

public void doubleField(FieldInfo fieldInfo,
 double value)
                 throws IOException

Process a double numeric field.

Throws:

IOException

needsField

public abstract StoredFieldVisitor.Status needsField(FieldInfo fieldInfo)
                                              throws IOException

Hook before processing a field. Before a field is processed, this method is invoked so that subclasses can return a StoredFieldVisitor.Status representing whether they need that particular field or not, or to stop processing entirely.

Throws:

IOException