Revision: 16316
http://gate.svn.sourceforge.net/gate/?rev=16316&view=rev
Author: valyt
Date: 2012-11-22 13:24:37 +0000 (Thu, 22 Nov 2012)
Log Message:
-----------
Simple query operator that returns a constant set of document IDs.
Added Paths:
-----------
mimir/trunk/mimir-core/src/gate/mimir/search/query/Const.java
Added: mimir/trunk/mimir-core/src/gate/mimir/search/query/Const.java
===================================================================
--- mimir/trunk/mimir-core/src/gate/mimir/search/query/Const.java
(rev 0)
+++ mimir/trunk/mimir-core/src/gate/mimir/search/query/Const.java
2012-11-22 13:24:37 UTC (rev 16316)
@@ -0,0 +1,143 @@
+/*
+ * Const.java
+ *
+ * Copyright (c) 2007-2011, The University of Sheffield.
+ *
+ * This file is part of GATE MÃmir (see http://gate.ac.uk/family/mimir.html),
+ * and is free software, licenced under the GNU Lesser General Public License,
+ * Version 3, June 2007 (also included with this distribution as file
+ * LICENCE-LGPL3.html).
+ *
+ * Valentin Tablan, 22 Nov 2012
+ *
+ * $Id$
+ */
+package gate.mimir.search.query;
+
+import gate.mimir.search.QueryEngine;
+
+import it.unimi.dsi.big.mg4j.index.Index;
+import it.unimi.dsi.big.mg4j.search.visitor.DocumentIteratorVisitor;
+import it.unimi.dsi.fastutil.objects.ReferenceArraySet;
+import it.unimi.dsi.fastutil.objects.ReferenceSet;
+
+import java.io.IOException;
+
+/**
+ * A query that returns a pre-defined (constant) list of document IDs. This
+ * query type does not support positions, so it returns no hits.
+ */
+public class Const implements QueryNode {
+
+ /**
+ * Executor implementation for {@link ConstQuery}. It returns document IDs
+ * from the predefined list, and no positions.
+ */
+ public static class ConstQueryExecutor extends AbstractQueryExecutor {
+
+ public ConstQueryExecutor(Const qNode, QueryEngine engine) {
+ super(engine, qNode);
+ this.documentIds = qNode.documentIds;
+ latestDocumentPosition = -1;
+ }
+
+ /**
+ * The position in the constant list of document IDs of the latest returned
+ * document.
+ */
+ private int latestDocumentPosition;
+
+ /**
+ * The predefined list of document IDs.
+ */
+ private long[] documentIds;
+
+ private ReferenceSet<Index> indices;
+
+ /* (non-Javadoc)
+ * @see gate.mimir.search.query.QueryExecutor#nextDocument(long)
+ */
+ @Override
+ public long nextDocument(long greaterThan) throws IOException {
+ do {
+ latestDocumentPosition++;
+ } while(latestDocumentPosition < documentIds.length &&
+ documentIds[latestDocumentPosition] <= greaterThan);
+ if(latestDocumentPosition < documentIds.length) {
+ latestDocument = documentIds[latestDocumentPosition];
+ } else {
+ latestDocument = -1;
+ }
+ return latestDocument;
+ }
+
+ /**
+ * This query executor type does not support positions, so it always
returns
+ * null.
+ * @see gate.mimir.search.query.QueryExecutor#nextHit()
+ */
+ @Override
+ public Binding nextHit() throws IOException {
+ return null;
+ }
+
+ /**
+ * Returns an empty set of indices.
+ * @see it.unimi.dsi.big.mg4j.search.DocumentIterator#indices()
+ */
+ @Override
+ public ReferenceSet<Index> indices() {
+ if(indices == null) {
+ indices = new ReferenceArraySet<Index>();
+ }
+ return indices;
+ }
+
+ /**
+ * Always returns null.
+ * @see
it.unimi.dsi.big.mg4j.search.DocumentIterator#accept(it.unimi.dsi.big.mg4j.search.visitor.DocumentIteratorVisitor)
+ */
+ @Override
+ public <T> T accept(DocumentIteratorVisitor<T> visitor) throws IOException
{
+ return null;
+ }
+
+ /**
+ * Always returns null
+ * @see
it.unimi.dsi.big.mg4j.search.DocumentIterator#acceptOnTruePaths(it.unimi.dsi.big.mg4j.search.visitor.DocumentIteratorVisitor)
+ */
+ @Override
+ public <T> T acceptOnTruePaths(DocumentIteratorVisitor<T> visitor)
+ throws IOException {
+ return null;
+ }
+ }
+
+ /* (non-Javadoc)
+ * @see
gate.mimir.search.query.QueryNode#getQueryExecutor(gate.mimir.search.QueryEngine)
+ */
+ @Override
+ public QueryExecutor getQueryExecutor(QueryEngine engine) throws IOException
{
+ return new ConstQueryExecutor(this, engine);
+ }
+
+
+ /**
+ * Creates a new Const query.
+ * @param documentIds the document IDs (in ascending order) that should be
+ * returned when this query is executed.
+ */
+ public Const(long[] documentIds) {
+ this.documentIds = documentIds;
+ }
+
+ private long[] documentIds;
+
+ /**
+ * @return the documentIds
+ */
+ public long[] getDocumentIds() {
+ return documentIds;
+ }
+
+}
Property changes on:
mimir/trunk/mimir-core/src/gate/mimir/search/query/Const.java
___________________________________________________________________
Added: svn:keywords
+ Id
Added: svn:eol-style
+ native
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