org.apache.lucene.search.spans
Class SpanMultiTermQueryWrapper<Q extends MultiTermQuery>

java.lang.Object
  org.apache.lucene.search.Query
      org.apache.lucene.search.spans.SpanQuery
          org.apache.lucene.search.spans.SpanMultiTermQueryWrapper<Q>

All Implemented Interfaces:

Serializable, Cloneable

Direct Known Subclasses:

SpanRegexQuery

public class SpanMultiTermQueryWrapper<Q extends MultiTermQuery>
extends SpanQuery

Wraps any MultiTermQuery as a SpanQuery, so it can be nested within other SpanQuery classes.

The query is rewritten by default to a SpanOrQuery containing the expanded terms, but this can be customized.

Example:

 WildcardQuery wildcard = new WildcardQuery(new Term("field", "bro?n"));
 SpanQuery spanWildcard = new SpanMultiTermQueryWrapper<WildcardQuery>(wildcard);
 // do something with spanWildcard, such as use it in a SpanFirstQuery
 
 

See Also:

Serialized Form

Nested Class Summary

static class	SpanMultiTermQueryWrapper.SpanRewriteMethod Abstract class that defines how the query is rewritten.
static class	SpanMultiTermQueryWrapper.TopTermsSpanBooleanQueryRewrite A rewrite method that first translates each term into a SpanTermQuery in a BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query.

Field Summary

protected Q	query
static SpanMultiTermQueryWrapper.SpanRewriteMethod	SCORING_SPAN_QUERY_REWRITE A rewrite method that first translates each term into a SpanTermQuery in a BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query.

Constructor Summary

SpanMultiTermQueryWrapper(Q query)
Create a new SpanMultiTermQueryWrapper.

Method Summary

boolean	equals(Object obj)
String	getField() Returns the name of the field matched by this query.
SpanMultiTermQueryWrapper.SpanRewriteMethod	getRewriteMethod() Expert: returns the rewriteMethod
Spans	getSpans(IndexReader reader) Expert: Returns the matches for this query in an index.
int	hashCode()
Query	rewrite(IndexReader reader) Expert: called to re-write queries into primitive queries.
void	setRewriteMethod(SpanMultiTermQueryWrapper.SpanRewriteMethod rewriteMethod) Expert: sets the rewrite method.
String	toString(String field) Prints a query to a string, with field assumed to be the default field and omitted.

Methods inherited from class org.apache.lucene.search.spans.SpanQuery

createWeight

Methods inherited from class org.apache.lucene.search.Query

clone, combine, extractTerms, getBoost, getSimilarity, mergeBooleanQueries, setBoost, toString, weight

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

query

protected final Q extends MultiTermQuery query

SCORING_SPAN_QUERY_REWRITE

public static final SpanMultiTermQueryWrapper.SpanRewriteMethod SCORING_SPAN_QUERY_REWRITE

A rewrite method that first translates each term into a SpanTermQuery in a BooleanClause.Occur.SHOULD clause in a BooleanQuery, and keeps the scores as computed by the query.

See Also:

setRewriteMethod(org.apache.lucene.search.spans.SpanMultiTermQueryWrapper.SpanRewriteMethod)

Constructor Detail

SpanMultiTermQueryWrapper

public SpanMultiTermQueryWrapper(Q query)

Create a new SpanMultiTermQueryWrapper.

Parameters:

query - Query to wrap.

NOTE: This will call MultiTermQuery.setRewriteMethod(MultiTermQuery.RewriteMethod) on the wrapped query, changing its rewrite method to a suitable one for spans. Be sure to not change the rewrite method on the wrapped query afterwards! Doing so will throw UnsupportedOperationException on rewriting this query! In Lucene 3.x, MultiTermQuery allows queries to rewrite to different field names, but SpanQuery needs a fixed field. The wrapped query must therefore support getField() or getTerm().

Throws:

IllegalArgumentException - if the wrapped query does not provide getField() or getTerm().

Method Detail

getRewriteMethod

public final SpanMultiTermQueryWrapper.SpanRewriteMethod getRewriteMethod()

Expert: returns the rewriteMethod

setRewriteMethod

public final void setRewriteMethod(SpanMultiTermQueryWrapper.SpanRewriteMethod rewriteMethod)

Expert: sets the rewrite method. This only makes sense to be a span rewrite method.

getSpans

public Spans getSpans(IndexReader reader)
               throws IOException

Description copied from class: SpanQuery

Expert: Returns the matches for this query in an index. Used internally to search for spans.

Specified by:

getSpans in class SpanQuery

Throws:

IOException

getField

public String getField()

Description copied from class: SpanQuery

Returns the name of the field matched by this query.

Specified by:

getField in class SpanQuery

toString

public String toString(String field)

Description copied from class: Query

Prints a query to a string, with field assumed to be the default field and omitted.

The representation used is one that is supposed to be readable by QueryParser. However, there are the following limitations:

• If the query was created by the parser, the printed representation may not be exactly what was parsed. For example, characters that need to be escaped will be represented without the required backslash.
• Some of the more complicated queries (e.g. span queries) don't have a representation that can be parsed by QueryParser.

Specified by:

toString in class Query

rewrite

public Query rewrite(IndexReader reader)
              throws IOException

Description copied from class: Query

Expert: called to re-write queries into primitive queries. For example, a PrefixQuery will be rewritten into a BooleanQuery that consists of TermQuerys.

Overrides:

rewrite in class Query

Throws:

IOException

hashCode

public int hashCode()

Overrides:

hashCode in class Query

equals

public boolean equals(Object obj)

Overrides:

equals in class Query