Merge pull request #5 from gm2211/feature/stream-from-iterator

1. Added public method to MoreStream to create a new stream from an i…

README.md

@@ -33,9 +33,11 @@ Each map function also accepts a [BiFunction], making it easy to modify keys bas
 
  * [Iterables][Iterable] (equivalent to the wordy `StreamSupport.stream(iterable.spliterator(), false)`)
  * [Optionals][] (equivalent to `optionalValue.map(Stream::of).orElse(Stream.of())`)
+ * [Iterators][Iterator] (equivalent to `StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED), false);`)
 
 [BiFunction]: https://docs.oracle.com/javase/8/docs/api/java/util/function/BiFunction.html
 [Iterable]: https://docs.oracle.com/javase/8/docs/api/java/lang/Iterable.html
+[Iterator]: https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html
 [Map]: https://docs.oracle.com/javase/8/docs/api/java/util/Map.html
 [Optionals]: https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html
 [Stream]: https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html

src/main/java/com/palantir/common/streams/MoreStreams.java

@@ -15,7 +15,10 @@
  */
 package com.palantir.common.streams;
 
+import java.util.Iterator;
 import java.util.Optional;
+import java.util.Spliterator;
+import java.util.Spliterators;
 import java.util.stream.Stream;
 import java.util.stream.StreamSupport;
 
@@ -43,5 +46,17 @@ public static <T> Stream<T> stream(Optional<T> optionalValue) {
         return optionalValue.map(Stream::of).orElse(Stream.of());
     }
 
+    /**
+     * Returns a stream from the provided iterator, preserving the iteration order.
+     *
+     * @param iterator Iterator for which a stream needs to be created
+     * @param <T> Type parameter for the iterator
+     * @return A stream for the iterator
+     */
+    public static <T> Stream<T> stream(Iterator<T> iterator) {
+        Spliterator<T> spliterator = Spliterators.spliteratorUnknownSize(iterator, Spliterator.ORDERED);
+        return StreamSupport.stream(spliterator, NOT_PARALLEL);
+    }
+
     private MoreStreams() {}
 }