Author: andy
Date: Fri Jun 20 18:52:42 2014
New Revision: 1604241
URL: http://svn.apache.org/r1604241
Log:
JENA-723 : Processing distinct must be done first
Modified:
jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/engine/iterator/QueryIterTopN.java
jena/trunk/jena-arq/src/main/java/org/apache/jena/atlas/lib/Tuple.java
Modified:
jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/engine/iterator/QueryIterTopN.java
URL:
http://svn.apache.org/viewvc/jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/engine/iterator/QueryIterTopN.java?rev=1604241&r1=1604240&r2=1604241&view=diff
==============================================================================
---
jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/engine/iterator/QueryIterTopN.java
(original)
+++
jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/engine/iterator/QueryIterTopN.java
Fri Jun 20 18:52:42 2014
@@ -39,23 +39,21 @@ import com.hp.hpl.jena.sparql.engine.bin
public class QueryIterTopN extends QueryIterPlainWrapper
{
+ /* We want to keep the N least elements (overall return is an ascending
sequence so limit+ascending = least).
+ * To do that we keep a priority heap of upto N eleemnts, ordered
descending.
+ * To keep another element, it must be less than the max so far.
+ * This leaves the least N in the heap.
+ */
private final QueryIterator embeddedIterator; // Keep a record of
the underlying source for .cancel.
- /* We want to keep the N least elements (overall return is an ascending
sequnce so limit+ascending = least).
- * To do that we keep a priority heap of upto N eleemnts, ordered
descending.
- * To keep another element, it must be less than the max so far.
- * This leaves the least N in the heap.
- */
private PriorityQueue<Binding> heap ;
private long limit ;
private final boolean distinct ;
- public QueryIterTopN(QueryIterator qIter, List<SortCondition> conditions,
long numItems, boolean distinct, ExecutionContext context)
- {
+ public QueryIterTopN(QueryIterator qIter, List<SortCondition> conditions,
long numItems, boolean distinct, ExecutionContext context) {
this(qIter, new BindingComparator(conditions, context), numItems,
distinct, context) ;
}
- public QueryIterTopN(QueryIterator qIter, Comparator<Binding> comparator,
long numItems, boolean distinct, ExecutionContext context)
- {
+ public QueryIterTopN(QueryIterator qIter, Comparator<Binding> comparator,
long numItems, boolean distinct, ExecutionContext context) {
super(null, context) ;
this.embeddedIterator = qIter ;
this.distinct = distinct ;
@@ -65,49 +63,39 @@ public class QueryIterTopN extends Query
limit = Long.MAX_VALUE ;
if ( limit < 0 )
- throw new QueryExecException("Negative LIMIT: "+limit) ;
-
- if ( limit == 0 )
- {
- // Keep Java happy.
- Iterator<Binding> iter0 = Iter.nullIterator() ;
+ throw new QueryExecException("Negative LIMIT: " + limit) ;
+
+ if ( limit == 0 ) {
+ // Keep Java happy.
+ Iterator<Binding> iter0 = Iter.nullIterator() ;
setIterator(iter0) ;
qIter.close() ;
return ;
}
-
- // Keep heap with maximum accessible.
+
+ // Keep heap with maximum accessible.
this.heap = new PriorityQueue<Binding>((int)numItems, new
ReverseComparator<Binding>(comparator)) ;
- this.setIterator(sortTopN(qIter, comparator));
+ this.setIterator(sortTopN(qIter, comparator)) ;
}
@Override
- public void requestCancel()
- {
- this.embeddedIterator.cancel();
+ public void requestCancel() {
+ this.embeddedIterator.cancel() ;
super.requestCancel() ;
}
-
- private Iterator<Binding> sortTopN(final QueryIterator qIter, final
Comparator<Binding> comparator)
- {
+
+ private Iterator<Binding> sortTopN(final QueryIterator qIter, final
Comparator<Binding> comparator) {
return new IteratorDelayedInitialization<Binding>() {
@Override
- protected Iterator<Binding> initializeIterator()
- {
- for ( ; qIter.hasNext() ; )
- {
+ protected Iterator<Binding> initializeIterator() {
+ for (; qIter.hasNext();) {
Binding binding = qIter.next() ;
if ( heap.size() < limit )
- add(binding) ;
+ add(binding) ;
else {
Binding currentMaxLeastN = heap.peek() ;
-
- if ( comparator.compare(binding, currentMaxLeastN) < 0
)
- {
- // If binding is less than current Nth least ...
- heap.poll() ; // Drop Nth least.
- add(binding) ;
- }
+ if ( comparator.compare(binding, currentMaxLeastN) < 0
)
+ add(binding) ;
}
}
qIter.close() ;
@@ -116,20 +104,16 @@ public class QueryIterTopN extends Query
Arrays.sort(y, comparator) ;
IteratorArray<Binding> iter = IteratorArray.create(y) ;
return iter ;
- }
- };
+ }
+ } ;
}
- private void add (Binding binding)
- {
- if ( distinct )
- {
- if ( !heap.contains(binding) ) heap.add(binding) ;
- }
- else
- {
- heap.add(binding) ;
- }
+ private void add(Binding binding) {
+ if ( distinct && heap.contains(binding) )
+ return ;
+ if ( heap.size() >= limit )
+ heap.poll() ; // Remove front element.
+ heap.add(binding) ;
}
}
Modified: jena/trunk/jena-arq/src/main/java/org/apache/jena/atlas/lib/Tuple.java
URL:
http://svn.apache.org/viewvc/jena/trunk/jena-arq/src/main/java/org/apache/jena/atlas/lib/Tuple.java?rev=1604241&r1=1604240&r2=1604241&view=diff
==============================================================================
--- jena/trunk/jena-arq/src/main/java/org/apache/jena/atlas/lib/Tuple.java
(original)
+++ jena/trunk/jena-arq/src/main/java/org/apache/jena/atlas/lib/Tuple.java Fri
Jun 20 18:52:42 2014
@@ -70,7 +70,7 @@ public class Tuple<T> implements Iterabl
protected final T[] tuple ;
- protected Tuple(T... tuple) {
+ protected Tuple(@SuppressWarnings("unchecked") T... tuple) {
this.tuple = tuple ;
}
