An abstract base class for search implementations.
Implements the main search methods.
Note that you can only access Hits from a Searcher as long as it is
not yet closed, otherwise an IOException will be thrown.
close
public abstract void close()
throws IOException
Frees resources associated with this Searcher.
Be careful not to call this method while you are still using objects
like
Hits
.
- close in interface Searchable
createWeight
protected Weight createWeight(Query query)
throws IOException
creates a weight for query
doc
public abstract Document doc(int i)
throws IOException
Expert: Returns the stored fields of document
i
.
Called by
HitCollector
implementations.
- doc in interface Searchable
docFreq
public abstract int docFreq(Term term)
throws IOException
Expert: Returns the number of documents containing term
.
Called by search code to compute term weights.
- docFreq in interface Searchable
docFreqs
public int[] docFreqs(Term[] terms)
throws IOException
Expert: For each term in the terms array, calculates the number of
documents containing term
. Returns an array with these
document frequencies. Used to minimize number of remote calls.
- docFreqs in interface Searchable
explain
public Explanation explain(Query query,
int doc)
throws IOException
Returns an Explanation that describes how
doc
scored against
query
.
This is intended to be used in developing Similarity implementations,
and, for good performance, should not be displayed with every hit.
Computing an explanation is as expensive as executing the query over the
entire index.
- explain in interface Searchable
explain
public abstract Explanation explain(Weight weight,
int doc)
throws IOException
Expert: low-level implementation method
Returns an Explanation that describes how
doc
scored against
weight
.
This is intended to be used in developing Similarity implementations,
and, for good performance, should not be displayed with every hit.
Computing an explanation is as expensive as executing the query over the
entire index.
Applications should call
explain(Query,int)
.
- explain in interface Searchable
getSimilarity
public Similarity getSimilarity()
Expert: Return the Similarity implementation used by this Searcher.
This defaults to the current value of
Similarity.getDefault()
.
maxDoc
public abstract int maxDoc()
throws IOException
Expert: Returns one greater than the largest possible document number.
Called by search code to compute term weights.
- maxDoc in interface Searchable
rewrite
public abstract Query rewrite(Query query)
throws IOException
Expert: called to re-write queries into primitive queries.
- rewrite in interface Searchable
search
public final Hits search(Query query)
throws IOException
Returns the documents matching query
.
search
public Hits search(Query query,
Filter filter)
throws IOException
Returns the documents matching query
and
filter
.
search
public TopFieldDocs search(Query query,
Filter filter,
int n,
Sort sort)
throws IOException
Expert: Low-level search implementation with arbitrary sorting. Finds
the top
n
hits for
query
, applying
filter
if non-null, and sorting the hits by the criteria in
sort
.
Applications should usually call
search(Query,Filter,Sort)
instead.
- search in interface Searchable
search
public void search(Query query,
Filter filter,
HitCollector results)
throws IOException
Lower-level search API.
HitCollector.collect(int,float)
is called for every non-zero
scoring document.
HitCollector-based access to remote indexes is discouraged.
Applications should only use this if they need
all of the
matching documents. The high-level search API (
search(Query)
) is usually more efficient, as it skips
non-high-scoring hits.
- search in interface Searchable
query
- to match documentsfilter
- if non-null, a bitset used to eliminate some documentsresults
- to receive hits
search
public Hits search(Query query,
Filter filter,
Sort sort)
throws IOException
Returns documents matching query
and filter
,
sorted by sort
.
search
public void search(Query query,
HitCollector results)
throws IOException
Lower-level search API.
HitCollector.collect(int,float)
is called for every non-zero
scoring document.
Applications should only use this if they need
all of the
matching documents. The high-level search API (
search(Query)
) is usually more efficient, as it skips
non-high-scoring hits.
Note: The
score
passed to this method is a raw score.
In other words, the score will not necessarily be a float whose value is
between 0 and 1.
search
public Hits search(Query query,
Sort sort)
throws IOException
Returns documents matching query
sorted by
sort
.
search
public abstract TopFieldDocs search(Weight weight,
Filter filter,
int n,
Sort sort)
throws IOException
Expert: Low-level search implementation with arbitrary sorting. Finds
the top
n
hits for
query
, applying
filter
if non-null, and sorting the hits by the criteria in
sort
.
Applications should usually call
search(Query,Filter,Sort)
instead.
- search in interface Searchable
search
public abstract void search(Weight weight,
Filter filter,
HitCollector results)
throws IOException
Lower-level search API.
HitCollector.collect(int,float)
is called for every non-zero
scoring document.
HitCollector-based access to remote indexes is discouraged.
Applications should only use this if they need
all of the
matching documents. The high-level search API (
search(Query)
) is usually more efficient, as it skips
non-high-scoring hits.
- search in interface Searchable
weight
- to match documentsfilter
- if non-null, a bitset used to eliminate some documentsresults
- to receive hits
setSimilarity
public void setSimilarity(Similarity similarity)
Expert: Set the Similarity implementation used by this Searcher.