src/share/classes/java/util/BitSet.java

rev 7009 : 8012645: Stream methods on BitSet, Random, ThreadLocalRandom, ZipFile
Contributed-by: akhil.arora@oracle.com, brian.goetz@oracle.com

*** 27,36 ****
--- 27,38 ----
  
  import java.io.*;
  import java.nio.ByteBuffer;
  import java.nio.ByteOrder;
  import java.nio.LongBuffer;
+ import java.util.stream.IntStream;
+ import java.util.stream.StreamSupport;
  
  /**
   * This class implements a vector of bits that grows as needed. Each
   * component of the bit set has a {@code boolean} value. The
   * bits of a {@code BitSet} are indexed by nonnegative integers.
*** 1186,1191 ****
--- 1188,1232 ----
          }
  
          b.append('}');
          return b.toString();
      }
+ 
+     /**
+      * Returns a stream of indices for which this {@code BitSet}
+      * contains a bit in the set state. The indices are returned
+      * in order, from lowest to highest. The size of the stream
+      * is the number of bits in the set state, equal to the value
+      * returned by the {@link #cardinality()} method.
+ 
+      * @return a stream of integers representing set indices
+      * @since 1.8
+      */
+     public IntStream stream() {
+         class BitSetIterator implements PrimitiveIterator.OfInt {
+             int next = nextSetBit(0);
+ 
+             @Override
+             public boolean hasNext() {
+                 return next != -1;
+             }
+ 
+             @Override
+             public int nextInt() {
+                 if (next != -1) {
+                     int ret = next;
+                     next = nextSetBit(next+1);
+                     return ret;
+                 } else {
+                     throw new NoSuchElementException();
+                 }
+             }
+         }
+ 
+         return StreamSupport.intStream(
+                 () -> Spliterators.spliterator(
+                         new BitSetIterator(), cardinality(),
+                         Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.SORTED),
+                 Spliterator.SIZED | Spliterator.SUBSIZED |
+                         Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.SORTED);
+     }
  }