Adding support for named graphs

hdt-api/src/main/java/org/rdfhdt/hdt/dictionary/Dictionary.java

@@ -99,6 +99,11 @@ public interface Dictionary extends Closeable {
 	 */
 	long getNobjects();
 
+	/**
+	 * Returns the number of objects in the dictionary. Note: Includes shared
+	 */
+	long getNgraphs();
+
 	/**
 	 * Returns the number of subjects/objects in the dictionary.
 	 */
@@ -111,6 +116,8 @@ public interface Dictionary extends Closeable {
 
 	DictionarySection getObjects();
 
+	DictionarySection getGraphs();
+
 	Map<? extends CharSequence, DictionarySection> getAllObjects();
 
 	DictionarySection getShared();
@@ -125,4 +132,10 @@ public interface Dictionary extends Closeable {
 	 * @return type
 	 */
 	String getType();
+
+	/**
+	 * Returns whether the dictionary supports graphs
+	 * @return true if it supports graphs, false otherwise
+	 */
+	boolean supportGraphs();
 }

hdt-api/src/main/java/org/rdfhdt/hdt/enums/DictionarySectionRole.java

@@ -4,5 +4,6 @@ public enum DictionarySectionRole {
 	SUBJECT,
 	PREDICATE,
 	OBJECT,
-	SHARED
+	SHARED,
+	GRAPH,
 }

hdt-api/src/main/java/org/rdfhdt/hdt/enums/TripleComponentRole.java

@@ -38,4 +38,6 @@ public enum TripleComponentRole {
 	PREDICATE,
 	/** The triple is an object */
 	OBJECT,
+	/** The triple is a graph */
+	GRAPH,
 }

hdt-api/src/main/java/org/rdfhdt/hdt/hdt/HDTVocabulary.java

@@ -84,6 +84,7 @@ public class HDTVocabulary {
 	public static final String DICTIONARY_TYPE_PLAIN = HDT_DICTIONARY_BASE+"Plain>";
 	public static final String DICTIONARY_TYPE_FOUR_SECTION = HDT_DICTIONARY_BASE+"Four>";
 	public static final String DICTIONARY_TYPE_MULT_SECTION = HDT_DICTIONARY_BASE+"Mult>";
+	public static final String DICTIONARY_TYPE_FOUR_QUAD_SECTION = HDT_DICTIONARY_BASE+"FourQuad>";
 
 	public static final String DICTIONARY_TYPE_FOUR_PSFC_SECTION = HDT_DICTIONARY_BASE+"FourPsfc>";
 
@@ -106,6 +107,7 @@ public class HDTVocabulary {
 	public static final String TRIPLES_TYPE_PLAIN = HDT_TRIPLES_BASE+"Plain>";
 	public static final String TRIPLES_TYPE_COMPACT = HDT_TRIPLES_BASE+"Compact>";
 	public static final String TRIPLES_TYPE_BITMAP = HDT_TRIPLES_BASE+"Bitmap>";
+	public static final String TRIPLES_TYPE_BITMAP_QUAD = HDT_TRIPLES_BASE+"BitmapQuad>";
 
 	// Index type
 	public static final String INDEX_TYPE_FOQ = HDT_BASE+"indexFoQ>";

hdt-api/src/main/java/org/rdfhdt/hdt/options/HDTOptionsKeys.java

@@ -263,6 +263,10 @@ public class HDTOptionsKeys {
 	 */
 	@Value(key = TEMP_DICTIONARY_IMPL_KEY, desc = "hash dictionary")
 	public static final String TEMP_DICTIONARY_IMPL_VALUE_HASH = "hash";
+	/**
+	 * use Hash quad to create the HDTQ
+	 */
+	public static final String TEMP_DICTIONARY_IMPL_VALUE_HASH_QUAD  = "hashQuad";
 	/**
 	 * use Hash map to create the HDT and store the multisection dictionary, mandatory to create MSC
 	 */
@@ -282,8 +286,13 @@ public class HDTOptionsKeys {
 	/**
 	 * 4 Section dictionary
 	 */
-	@Value(key = DICTIONARY_TYPE_KEY, desc = "Four sectiob dictionary")
+	@Value(key = DICTIONARY_TYPE_KEY, desc = "Four section dictionary")
 	public static final String DICTIONARY_TYPE_VALUE_FOUR_SECTION = HDTVocabulary.DICTIONARY_TYPE_FOUR_SECTION;
+	/*
+	 * 4 Quad Section dictionary
+	 */
+	@Value(key = DICTIONARY_TYPE_KEY, desc = "Four quad section dictionary")
+	public static final String DICTIONARY_TYPE_VALUE_FOUR_QUAD_SECTION = HDTVocabulary.DICTIONARY_TYPE_FOUR_QUAD_SECTION;
 	/**
 	 * Prefix AND Suffix front-coded (PSFC) 4 Section dictionary
 	 */

hdt-api/src/main/java/org/rdfhdt/hdt/quad/QuadString.java

@@ -18,7 +18,7 @@ public QuadString(CharSequence subject, CharSequence predicate, CharSequence obj
 
 	public QuadString(TripleString other) {
 		super(other);
-		this.context = other.getObject();
+		this.context = other.getGraph();
 	}
 
 	@Override
@@ -29,9 +29,6 @@ public void clear() {
 
 	@Override
 	public boolean equals(Object other) {
-		if (context.length() == 0) {
-			return super.equals(other);
-		}
 		if (!(other instanceof QuadString)) {
 			return false;
 		}
@@ -116,4 +113,9 @@ public int hashCode() {
 	public QuadString tripleToString() {
 		return new QuadString(subject.toString(), predicate.toString(), object.toString(), context.toString());
 	}
+
+	@Override
+	public String toString() {
+		return super.toString() + " " + context;
+	}
 }

hdt-api/src/main/java/org/rdfhdt/hdt/rdf/RDFAccess.java

@@ -52,4 +52,28 @@ public interface RDFAccess {
 	 * @throws NotFoundException when the triple cannot be found
 	 */
 	IteratorTripleString search(CharSequence subject, CharSequence predicate, CharSequence object) throws NotFoundException;
+
+	/**
+	 * Iterate over the triples of an RDF Set that match the specified pattern.
+	 * null and empty strings act as a wildcard. 
+	 * (e.g. search(null, null, null, null) iterates over all elements)
+	 * 
+	 * @param subject
+	 *            The subject to search
+	 * @param predicate
+	 *            The predicate to search
+	 * @param object
+	 *            The object to search
+	 * @param graph
+	 *            The graph to search
+	 * 
+	 * @return Iterator of TripleStrings
+	 * @throws NotFoundException when the triple cannot be found
+	 */
+	IteratorTripleString search(
+		CharSequence subject,
+		CharSequence predicate,
+		CharSequence object,
+		CharSequence graph
+	) throws NotFoundException;
 }

hdt-api/src/main/java/org/rdfhdt/hdt/triples/TripleID.java

@@ -43,6 +43,8 @@ public final class TripleID implements Comparable<TripleID>, Serializable, Clone
 	private long subject;
 	private long predicate;
 	private long object;
+	private long graph;
+	private boolean isQuad = false;
 
 	/**
 	 * Basic constructor
@@ -68,6 +70,27 @@ public TripleID(long subject, long predicate, long object) {
 		this.object = object;
 	}
 
+	/**
+	 * Constructor
+	 * 
+	 * @param subject
+	 * 		  The subject
+	 * @param predicate
+	 * 		  The predicate
+	 * @param object
+	 * 		  The object
+	 * @param graph
+	 * 		  The graph
+	 */
+	public TripleID(long subject, long predicate, long object, long graph) {
+		super();
+		this.subject = subject;
+		this.predicate = predicate;
+		this.object = object;
+		this.graph = graph;
+		this.isQuad = true;
+	}
+
 	/**
 	 * Build a TripleID as a copy of another one.
 	 * @param other the triple ID to copy
@@ -77,6 +100,12 @@ public TripleID(TripleID other) {
 		this.subject = other.subject;
 		this.predicate = other.predicate;
 		this.object = other.object;
+		this.graph = other.graph;
+		this.isQuad = other.isQuad;
+	}
+
+	public boolean isQuad() {
+		return isQuad;
 	}
 
 	/**
@@ -124,6 +153,22 @@ public void setPredicate(long predicate) {
 		this.predicate = predicate;
 	}
 
+	/**
+	 * @return long the graph
+	 */
+	public long getGraph() {
+		return graph;
+	}
+
+	/**
+	 * @param graph
+	 *            the graph to set
+	 */
+	public void setGraph(long graph) {
+		this.graph = graph;
+		this.isQuad = true;
+	}
+
 	/**
 	 * Replace all components of a TripleID at once. Useful to reuse existing objects.
 	 * @param subject subject ID
@@ -136,17 +181,35 @@ public void setAll(long subject, long predicate, long object) {
 		this.object = object;
 	}
 
+	/**
+	 * Replace all components of a TripleID at once. Useful to reuse existing objects.
+	 * @param subject subject ID
+	 * @param predicate predicate ID
+	 * @param object object ID
+	 * @param graph graph ID
+	 */
+	public void setAll(long subject, long predicate, long object, long graph) {
+		this.subject = subject;
+		this.predicate = predicate;
+		this.object = object;
+		this.graph = graph;
+		this.isQuad = true;
+	}
+
 	public void assign(TripleID replacement) {
 		subject = replacement.getSubject();
         object = replacement.getObject();
         predicate = replacement.getPredicate();
+		graph = replacement.getGraph();
+		isQuad = replacement.isQuad();
 	}
 
 	/**
 	 * Set all components to zero.
 	 */
 	public void clear() {
-		subject = predicate = object = 0;
+		subject = predicate = object = graph = 0;
+		isQuad = false;
 	}
 
 	/*
@@ -156,6 +219,8 @@ public void clear() {
 	 */
 	@Override
 	public String toString() {
+		if (isQuad)
+			return subject + " " + predicate + " " + object + " " + graph;
 		return subject + " " + predicate + " " + object;
 	}
 
@@ -192,11 +257,13 @@ public boolean match(TripleID pattern) {
 		long subjectPattern = pattern.getSubject();
 		long predicatePattern = pattern.getPredicate();
 		long objectPattern = pattern.getObject();
+		long graphPattern = pattern.getGraph();
 
-		/* Remember that 0 acts as a wildcard */
 		if (subjectPattern == 0 || this.subject == subjectPattern) {
 			if (predicatePattern == 0 || this.predicate == predicatePattern) {
-				return objectPattern == 0 || this.object == objectPattern;
+				if (objectPattern == 0 || this.object == objectPattern) {
+					return graphPattern == 0 || this.graph == graphPattern;
+				}
 			}
 		}
 		return false;
@@ -207,23 +274,23 @@ public boolean match(TripleID pattern) {
 	 * @return boolean
 	 */
 	public boolean isEmpty() {
-		return !(subject != 0 || predicate != 0 || object != 0);
+		return !(subject != 0 || predicate != 0 || object != 0 || graph != 0);
 	}
 
 	/**
 	 * Check whether none of the components of the triple are empty.
 	 * @return boolean
 	 */
 	public boolean isValid() {
-		return subject>0 && predicate>0 && object>0;
+		return subject>0 && predicate>0 && object>0 && (isQuad ? graph>0 : true);
 	}
 
 	/**
 	 * Checks whether any of the components of the triple are "no match" (-1).
 	 * @return boolean
 	 */
 	public boolean isNoMatch() {
-		return subject == -1 || predicate == -1 || object == -1;
+		return subject == -1 || predicate == -1 || object == -1 || graph == -1;
 	}
 
 	/**
@@ -234,7 +301,8 @@ public String getPatternString() {
 		return "" +
 			(subject==0   ? '?' : 'S') +
 			(predicate==0 ? '?' : 'P') +
-			(object==0    ? '?' : 'O');
+			(object==0    ? '?' : 'O') +
+			(isQuad ? (graph==0 ? '?' : 'G') : "");
 	}
 
 	/**
@@ -252,7 +320,7 @@ public boolean equals(Object o) {
 			return false;
 		}
 		TripleID other = (TripleID) o;
-		return !( subject!=other.subject || predicate!=other.predicate || object!=other.object );
+		return !( subject!=other.subject || predicate!=other.predicate || object!=other.object || graph!=other.graph );
 	}
 
 	@Override
@@ -266,6 +334,6 @@ public TripleID clone() {
 
 	@Override
 	public int hashCode() {
-		return (int) (subject * 13 + predicate * 17 + object * 31);
+		return (int) (subject * 13 + predicate * 17 + object * 31 + graph * 37);
 	}
 }