org.apache.lucene.search

Interface Searchable

public interface Searchable extends Remote

The interface for search implementations.

Searchable is the abstract network protocol for searching. Implementations provide search over a single index, over multiple indices, and over indices on remote servers.

Queries, filters and sort criteria are designed to be compact so that they may be efficiently passed to a remote index, with only the top-scoring hits being returned, rather than every non-zero scoring hit.

Method Summary
voidclose()
Frees resources associated with this Searcher.
Documentdoc(int i)
Expert: Returns the stored fields of document i.
Documentdoc(int n, FieldSelector fieldSelector)
Get the Document at the nth position.
intdocFreq(Term term)
Expert: Returns the number of documents containing term.
int[]docFreqs(Term[] terms)
Expert: For each term in the terms array, calculates the number of documents containing term.
Explanationexplain(Weight weight, int doc)
Expert: low-level implementation method Returns an Explanation that describes how doc scored against weight.
intmaxDoc()
Expert: Returns one greater than the largest possible document number.
Queryrewrite(Query query)
Expert: called to re-write queries into primitive queries.
voidsearch(Weight weight, Filter filter, HitCollector results)
Lower-level search API.
TopDocssearch(Weight weight, Filter filter, int n)
Expert: Low-level search implementation.
TopFieldDocssearch(Weight weight, Filter filter, int n, Sort sort)
Expert: Low-level search implementation with arbitrary sorting.

Method Detail

close

public void close()
Frees resources associated with this Searcher. Be careful not to call this method while you are still using objects like Hits.

doc

public Document doc(int i)
Expert: Returns the stored fields of document i. Called by HitCollector implementations.

Throws: CorruptIndexException if the index is corrupt IOException if there is a low-level IO error

See Also: IndexReader

doc

public Document doc(int n, FieldSelector fieldSelector)
Get the Document at the nth position. The FieldSelector may be used to determine what Fields to load and how they should be loaded. NOTE: If the underlying Reader (more specifically, the underlying FieldsReader) is closed before the lazy Field is loaded an exception may be thrown. If you want the value of a lazy Field to be available after closing you must explicitly load it or fetch the Document again with a new loader.

Parameters: n Get the document at the nth position fieldSelector The FieldSelector to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.

Returns: The stored fields of the Document at the nth position

Throws: CorruptIndexException if the index is corrupt IOException if there is a low-level IO error

See Also: IndexReader Fieldable FieldSelector SetBasedFieldSelector LoadFirstFieldSelector

docFreq

public int docFreq(Term term)
Expert: Returns the number of documents containing term. Called by search code to compute term weights.

See Also: docFreq

docFreqs

public int[] docFreqs(Term[] terms)
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.

explain

public Explanation explain(Weight weight, int doc)
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 Searcher.

Throws: BooleanQuery.TooManyClauses

maxDoc

public int maxDoc()
Expert: Returns one greater than the largest possible document number. Called by search code to compute term weights.

See Also: maxDoc

rewrite

public Query rewrite(Query query)
Expert: called to re-write queries into primitive queries.

Throws: BooleanQuery.TooManyClauses

search

public void search(Weight weight, Filter filter, HitCollector results)
Lower-level search API.

HitCollector 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) is usually more efficient, as it skips non-high-scoring hits.

Parameters: weight to match documents filter if non-null, a bitset used to eliminate some documents results to receive hits

Throws: BooleanQuery.TooManyClauses

search

public TopDocs search(Weight weight, Filter filter, int n)
Expert: Low-level search implementation. Finds the top n hits for query, applying filter if non-null.

Called by Hits.

Applications should usually call search or search instead.

Throws: BooleanQuery.TooManyClauses

search

public TopFieldDocs search(Weight weight, Filter filter, int n, Sort sort)
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 instead.

Throws: BooleanQuery.TooManyClauses

Copyright © 2000-2007 Apache Software Foundation. All Rights Reserved.