gate.mimir.search.query

Class AndQuery.AndQueryExecutor

java.lang.Object

gate.mimir.search.query.AbstractQueryExecutor

gate.mimir.search.query.AbstractIntersectionQueryExecutor

gate.mimir.search.query.AndQuery.AndQueryExecutor

All Implemented Interfaces:

QueryExecutor, it.unimi.di.big.mg4j.search.DocumentIterator

Enclosing class:

AndQuery

public static class AndQuery.AndQueryExecutor
extends AbstractIntersectionQueryExecutor

Field Summary

Fields

Modifier and Type	Field and Description
protected List<Binding[]>	hitsOnCurrentDocument The list of available hits for the current document (i.e.

Fields inherited from class gate.mimir.search.query.AbstractIntersectionQueryExecutor

executors, indices, nextDocIDs, nodes

Fields inherited from class gate.mimir.search.query.AbstractQueryExecutor

closed, engine, latestDocument, queryNode

Fields inherited from interface it.unimi.di.big.mg4j.search.DocumentIterator

END_OF_LIST

Constructor Summary

Constructors

Constructor and Description
AndQueryExecutor(AndQuery query, QueryEngine engine) Creates a query executor for an AND query.

Method Summary

Modifier and Type	Method and Description
void	close() Closes this QueryExecutor and releases all resources used.
protected void	getHitsOnCurrentDocument()
long	nextDocument(long greaterThan) Gets the next document that contains a match, with a document ID greater than the ID provided in the from parameter.
Binding	nextHit() Gets the next matching position, in the document last returned by DocumentIterator.nextDocument().

Methods inherited from class gate.mimir.search.query.AbstractIntersectionQueryExecutor

accept, acceptOnTruePaths, indices

Methods inherited from class gate.mimir.search.query.AbstractQueryExecutor

dispose, document, getLatestDocument, getQueryEngine, getQueryNode, intervalIterator, intervalIterator, intervalIterators, mayHaveNext, nextDocument, skipTo, weight, weight

Methods inherited from class java.lang.Object

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

Field Detail

hitsOnCurrentDocument

protected List<Binding[]> hitsOnCurrentDocument

The list of available hits for the current document (i.e. the latest document returned by #nextDocument(int). Each entry is an array of Binding values, one from each sub-query.

Constructor Detail

AndQueryExecutor

public AndQueryExecutor(AndQuery query,
                        QueryEngine engine)
                 throws IOException

Creates a query executor for an AND query.

Parameters:

engine - the QueryEngine to be used.

query - the query being executed.

Throws:

IOException - if there are problems accessing the index.

Method Detail

close

public void close()
           throws IOException

Description copied from interface: QueryExecutor

Closes this QueryExecutor and releases all resources used.

Specified by:

close in interface QueryExecutor

Overrides:

close in class AbstractIntersectionQueryExecutor

Throws:

IOException - if the index files cannot be accessed.

nextDocument

public long nextDocument(long greaterThan)
                  throws IOException

Description copied from interface: QueryExecutor

Gets the next document that contains a match, with a document ID greater than the ID provided in the from parameter. This method essentially requests the query executor to skip over a number of documents that are not desired for external reasons (e.g. when running a complex query, other query constraints may have already removed a set of documents from the candidate list). The query executor will never roll back: all document IDs returned are in ascending order. This means that if the value provided for the greaterThan parameter is lower than the latest document ID returned, it will have no effect.

Specified by:

nextDocument in interface QueryExecutor

Overrides:

nextDocument in class AbstractIntersectionQueryExecutor

Parameters:

greaterThan - a document ID representing the lowest bound (exclusive) for the requested document ID.

Returns:

the matching document ID, or -1 if no more documents match the query. The returned value will be strictly greater than greaterThan, or -1 if no more matching documents are found.

Throws:

IOException - if the index files cannot be accessed.

getHitsOnCurrentDocument

protected void getHitsOnCurrentDocument()
                                 throws IOException

Throws:

IOException

nextHit

public Binding nextHit()
                throws IOException

Description copied from interface: QueryExecutor

Gets the next matching position, in the document last returned by DocumentIterator.nextDocument(). Hits are always returned in increasing order of start offset, but hits that start at the same place may be returned in any order (i.e. not necessarily longest first or shortest first).

Returns:

the Binding corresponding to the root query node for this executor. If no further matches are possible on the current document, then null is returned.

Throws:

IOException - if the index files cannot be accessed.