org.apache.lucene.util.fst
Class FST<T>

java.lang.Object
  org.apache.lucene.util.fst.FST<T>

public class FST<T>
extends Object

Represents an FST using a compact byte[] format.

The format is similar to what's used by Morfologik (http://sourceforge.net/projects/morfologik).

NOTE: the FST cannot be larger than ~2.1 GB because it uses int to address the byte[].

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

Nested Class Summary

static class	FST.Arc<T>
static class	FST.INPUT_TYPE

Field Summary

int	arcCount
int	arcWithOutputCount
static int	END_LABEL
FST.INPUT_TYPE	inputType
int	nodeCount
Outputs<T>	outputs

Constructor Summary

FST(DataInput in, Outputs<T> outputs)

FST(FST.INPUT_TYPE inputType, Outputs<T> outputs)

Method Summary

FST.Arc<T>	findTargetArc(int labelToMatch, FST.Arc<T> follow, FST.Arc<T> arc) Finds an arc leaving the incoming arc, replacing the arc in place.
int	getArcCount()
int	getArcWithOutputCount()
FST.Arc<T>	getFirstArc(FST.Arc<T> arc) Fills virtual 'start' arc, ie, an empty incoming arc to the FST's start node
FST.INPUT_TYPE	getInputType()
int	getNodeCount()
FST.Arc<T>	readFirstTargetArc(FST.Arc<T> follow, FST.Arc<T> arc) Follow the follow arc and read the first arc of its target; this changes the provided arc (2nd arg) in-place and returns it.
FST.Arc<T>	readLastTargetArc(FST.Arc<T> follow, FST.Arc<T> arc) Follows the follow arc and reads the last arc of its target; this changes the provided arc (2nd arg) in-place and returns it.
FST.Arc<T>	readNextArc(FST.Arc<T> arc) In-place read; returns the arc.
int	readNextArcLabel(FST.Arc<T> arc) Peeks at next arc's label; does not alter arc.
void	save(DataOutput out)
int	sizeInBytes() Returns bytes used to represent the FST
boolean	targetHasArcs(FST.Arc<T> arc)

Methods inherited from class java.lang.Object

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

Field Detail

inputType

public final FST.INPUT_TYPE inputType

outputs

public final Outputs<T> outputs

nodeCount

public int nodeCount

arcCount

public int arcCount

arcWithOutputCount

public int arcWithOutputCount

END_LABEL

public static final int END_LABEL

See Also:

Constant Field Values

Constructor Detail

FST

public FST(FST.INPUT_TYPE inputType,
           Outputs<T> outputs)

FST

public FST(DataInput in,
           Outputs<T> outputs)
    throws IOException

Throws:

IOException

Method Detail

getInputType

public FST.INPUT_TYPE getInputType()

sizeInBytes

public int sizeInBytes()

Returns bytes used to represent the FST

save

public void save(DataOutput out)
          throws IOException

Throws:

IOException

targetHasArcs

public boolean targetHasArcs(FST.Arc<T> arc)

getFirstArc

public FST.Arc<T> getFirstArc(FST.Arc<T> arc)

Fills virtual 'start' arc, ie, an empty incoming arc to the FST's start node

readLastTargetArc

public FST.Arc<T> readLastTargetArc(FST.Arc<T> follow,
                                    FST.Arc<T> arc)
                             throws IOException

Follows the follow arc and reads the last arc of its target; this changes the provided arc (2nd arg) in-place and returns it.

Returns:

Returns the second argument (arc).

Throws:

IOException

readFirstTargetArc

public FST.Arc<T> readFirstTargetArc(FST.Arc<T> follow,
                                     FST.Arc<T> arc)
                              throws IOException

Follow the follow arc and read the first arc of its target; this changes the provided arc (2nd arg) in-place and returns it.

Returns:

Returns the second argument (arc).

Throws:

IOException

readNextArc

public FST.Arc<T> readNextArc(FST.Arc<T> arc)
                       throws IOException

In-place read; returns the arc.

Throws:

IOException

readNextArcLabel

public int readNextArcLabel(FST.Arc<T> arc)
                     throws IOException

Peeks at next arc's label; does not alter arc. Do not call this if arc.isLast()!

Throws:

IOException

findTargetArc

public FST.Arc<T> findTargetArc(int labelToMatch,
                                FST.Arc<T> follow,
                                FST.Arc<T> arc)
                         throws IOException

Finds an arc leaving the incoming arc, replacing the arc in place. This returns null if the arc was not found, else the incoming arc.

Throws:

IOException

getNodeCount

public int getNodeCount()

getArcCount

public int getArcCount()

getArcWithOutputCount

public int getArcWithOutputCount()