org.apache.lucene.index

Class TermStates

java.lang.Object

org.apache.lucene.index.TermStates

public final class TermStates
extends Object

Maintains a IndexReader TermState view over IndexReader instances containing a single term. The TermStates doesn't track if the given TermState objects are valid, neither if the TermState instances refer to the same terms in the associated readers.

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

Constructor Summary

Constructors

Constructor and Description
TermStates(IndexReaderContext context) Creates an empty TermStates from a IndexReaderContext
TermStates(IndexReaderContext context, TermState state, int ord, int docFreq, long totalTermFreq) Creates a TermStates with an initial TermState, IndexReader pair.

Method Summary

Modifier and Type	Method and Description
void	accumulateStatistics(int docFreq, long totalTermFreq) Expert: Accumulate term statistics.
static TermStates	build(IndexReaderContext context, Term term, boolean needsStats) Creates a TermStates from a top-level IndexReaderContext and the given Term.
void	clear() Clears the TermStates internal state and removes all registered TermStates
int	docFreq() Returns the accumulated document frequency of all TermState instances passed to register(TermState, int, int, long).
TermState	get(LeafReaderContext ctx) Returns the TermState for a leaf reader context or null if no TermState for the context was registered.
void	register(TermState state, int ord) Expert: Registers and associates a TermState with an leaf ordinal.
void	register(TermState state, int ord, int docFreq, long totalTermFreq) Registers and associates a TermState with an leaf ordinal.
String	toString()
long	totalTermFreq() Returns the accumulated term frequency of all TermState instances passed to register(TermState, int, int, long).
boolean	wasBuiltFor(IndexReaderContext context) Expert: Return whether this TermStates was built for the given IndexReaderContext.

Methods inherited from class java.lang.Object

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

Constructor Detail

TermStates

public TermStates(IndexReaderContext context)

Creates an empty TermStates from a IndexReaderContext

TermStates

public TermStates(IndexReaderContext context,
                  TermState state,
                  int ord,
                  int docFreq,
                  long totalTermFreq)

Creates a TermStates with an initial TermState, IndexReader pair.

Method Detail

wasBuiltFor

public boolean wasBuiltFor(IndexReaderContext context)

Expert: Return whether this TermStates was built for the given IndexReaderContext. This is typically used for assertions.

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

build

public static TermStates build(IndexReaderContext context,
                               Term term,
                               boolean needsStats)
                        throws IOException

Creates a TermStates from a top-level IndexReaderContext and the given Term. This method will lookup the given term in all context's leaf readers and register each of the readers containing the term in the returned TermStates using the leaf reader's ordinal.

Note: the given context must be a top-level context.

Parameters:

needsStats - if true then all leaf contexts will be visited up-front to collect term statistics. Otherwise, the TermState objects will be built only when requested

Throws:

IOException

clear

public void clear()

Clears the TermStates internal state and removes all registered TermStates

register

public void register(TermState state,
                     int ord,
                     int docFreq,
                     long totalTermFreq)

Registers and associates a TermState with an leaf ordinal. The leaf ordinal should be derived from a IndexReaderContext's leaf ord.

register

public void register(TermState state,
                     int ord)

Expert: Registers and associates a TermState with an leaf ordinal. The leaf ordinal should be derived from a IndexReaderContext's leaf ord. On the contrary to register(TermState, int, int, long) this method does NOT update term statistics.

accumulateStatistics

public void accumulateStatistics(int docFreq,
                                 long totalTermFreq)

Expert: Accumulate term statistics.

get

public TermState get(LeafReaderContext ctx)
              throws IOException

Returns the TermState for a leaf reader context or null if no TermState for the context was registered.

Parameters:

ctx - the LeafReaderContext to get the TermState for.

Returns:

the TermState for the given readers ord or null if no TermState for the reader was registered

Throws:

IOException

docFreq

public int docFreq()

Returns the accumulated document frequency of all TermState instances passed to register(TermState, int, int, long).

Returns:

the accumulated document frequency of all TermState instances passed to register(TermState, int, int, long).

totalTermFreq

public long totalTermFreq()

Returns the accumulated term frequency of all TermState instances passed to register(TermState, int, int, long).

Returns:

the accumulated term frequency of all TermState instances passed to register(TermState, int, int, long).

toString

public String toString()

Overrides:

toString in class Object