Iterator#iterate based on comments from @danieldietrich and @paplorinc

vavr-io · Jul 9, 2016 · f369a5c · f369a5c
1 parent 3d76301
commit f369a5c
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 6 deletions.
diff --git a/javaslang/src/main/java/javaslang/collection/Iterator.java b/javaslang/src/main/java/javaslang/collection/Iterator.java
@@ -968,8 +968,11 @@ public T getNext() {
     static <T> Iterator<T> iterate(T seed, Function<? super T, ? extends T> f) {
         Objects.requireNonNull(f, "f is null");
         return new AbstractIterator<T>() {
-            Function<? super T, ? extends T> nextFunc = (s) -> seed;
-            T previous = null;
+            Function<? super T, ? extends T> nextFunc = s -> {
+                nextFunc = f;
+                return seed;
+            };
+            T current = null;
 
             @Override
             public boolean hasNext() {
@@ -978,9 +981,8 @@ public boolean hasNext() {
 
             @Override
             public T getNext() {
-                previous = nextFunc.apply(previous);
-                nextFunc = f;
-                return previous;
+                current = nextFunc.apply(current);
+                return current;
             }
         };
     }

diff --git a/javaslang/src/test/java/javaslang/collection/IteratorTest.java b/javaslang/src/test/java/javaslang/collection/IteratorTest.java
@@ -362,7 +362,7 @@ public void shouldGenerateInfiniteStreamBasedOnSupplierWithAccessToPreviousValue
 
     @Test
     public void shouldNotCallSupplierUntilNecessary() {
-        assertThat(iterate(2, (i) -> {throw new RuntimeException("The supplier function should not be called since the next value is not needed in order to get head.");}).head()).isEqualTo(2);
+        assertThat(iterate(2, (i) -> {throw new RuntimeException();}).head()).isEqualTo(2);
     }
 
     // ++++++ OBJECT ++++++