Updated iterators to track number of entries retrieved, potentially r…

…educing total reads by one.

core/src/main/java/me/prettyprint/cassandra/model/IndexedSlicesQuery.java

@@ -124,6 +124,10 @@ public IndexedSlicesQuery<K, N, V> setRowCount(int rowCount) {
     return this;
   }
 
+	public int getRowCount() {
+		return indexClause.getCount();
+	}
+
   @Override
   public QueryResult<OrderedRows<K, N, V>> execute() {
 

core/src/main/java/me/prettyprint/cassandra/service/ColumnSliceIterator.java

@@ -5,6 +5,7 @@
 import me.prettyprint.hector.api.query.SliceQuery;
 
 /**
+ * Iterates over the column slice, refreshing until all qualifing columns are retrieved.
  *
  * @author thrykol
  */
@@ -16,6 +17,7 @@ public class ColumnSliceIterator<K, N, V> implements Iterator {
 	private ColumnSliceFinish<N> finish;
 	private boolean reversed;
 	private int count = 100;
+	private int columns = 0;
 
 	/**
 	 * Constructor
@@ -28,6 +30,7 @@ public class ColumnSliceIterator<K, N, V> implements Iterator {
 	public ColumnSliceIterator(SliceQuery<K, N, V> query, N start, final N finish, boolean reversed) {
 		this(query, start, new ColumnSliceFinish<N>() {
 
+			@Override
 			public N function() {
 				return finish;
 			}
@@ -51,12 +54,14 @@ public ColumnSliceIterator(SliceQuery<K, N, V> query, N start, ColumnSliceFinish
 		this.query.setRange(this.start, this.finish.function(), this.reversed, count);
 	}
 
+	@Override
 	public boolean hasNext() {
 		if (iterator == null) {
 			iterator = query.execute().get().getColumns().iterator();
-		} else if (!iterator.hasNext()) {
+		} else if (!iterator.hasNext() && columns == count) {  // only need to do another query if maximum columns were retrieved
 			query.setRange(start, finish.function(), reversed, count);
 			iterator = query.execute().get().getColumns().iterator();
+			columns = 0;
 
 			// First element is start which was the last element on the previous query result - skip it
 			if (iterator.hasNext()) {
@@ -67,13 +72,16 @@ public boolean hasNext() {
 		return iterator.hasNext();
 	}
 
+	@Override
 	public HColumn<N, V> next() {
 		HColumn<N, V> column = iterator.next();
 		start = column.getName();
+		columns++;
 
 		return column;
 	}
 
+	@Override
 	public void remove() {
 		iterator.remove();
 	}

core/src/main/java/me/prettyprint/cassandra/service/IndexedSlicesIterator.java

@@ -5,6 +5,7 @@
 import me.prettyprint.hector.api.beans.Row;
 
 /**
+ * Iterates over the index slices, automatically refreshing the query until all matching rows are returned.
  *
  * @author thrykol
  */
@@ -13,6 +14,7 @@ public class IndexedSlicesIterator<K, N, V> implements Iterator {
 	private IndexedSlicesQuery<K, N, V> query;
 	private K startKey;
 	private Iterator<Row<K, N, V>> iterator;
+	private int rows = 0;
 
 	public IndexedSlicesIterator(IndexedSlicesQuery<K, N, V> query, K startKey) {
 		this.query = query;
@@ -21,14 +23,16 @@ public IndexedSlicesIterator(IndexedSlicesQuery<K, N, V> query, K startKey) {
 		this.query.setStartKey(startKey);
 	}
 
+	@Override
 	public boolean hasNext() {
 		if (iterator == null) {
 			// First time through
 			iterator = query.execute().get().getList().iterator();
-		} else if (!iterator.hasNext()) {
+		} else if (!iterator.hasNext() && rows == query.getRowCount()) {  // only need to do another query if maximum rows were retrieved
 			query.setStartKey(startKey);
 			iterator = query.execute().get().getList().iterator();
-
+			rows = 0;
+
 			if (iterator.hasNext()) {
 				// First element is startKey which was the last element on the previous query result - skip it
 				iterator.next();
@@ -38,13 +42,16 @@ public boolean hasNext() {
 		return iterator.hasNext();
 	}
 
+	@Override
 	public Row<K, N, V> next() {
 		Row<K, N, V> row = iterator.next();
 		startKey = row.getKey();
+		rows++;
 
 		return row;
 	}
 
+	@Override
 	public void remove() {
 		iterator.remove();
 	}