LinkedList Iterator

yangdd1205 · yangdd1205 · commit 3ab6f5eb4927 · 2017-02-24T18:57:04.000+08:00
diff --git a/group18/1049843090/src/com/coding/basic/LinkedList.java b/group18/1049843090/src/com/coding/basic/LinkedList.java
@@ -202,4 +202,37 @@ public Node(E data, Node<E> next) {
             this.next = next;
         }
     }
+
+    public Iterator iterator(){
+        return new LinkedListIterator<>();
+    }
+
+    private class LinkedListIterator<E> implements Iterator<E>{
+
+        private int cursor;//游标
+
+        private int lastRet = -1;//可被删除元素下标
+
+        @Override
+        public boolean hasNext() {
+            return cursor!=size;
+        }
+
+        @Override
+        public E next() {
+            int i = cursor;
+            cursor++;
+            return (E) LinkedList.this.get(lastRet=i);
+        }
+
+        @Override
+        public void remove() {
+            if(lastRet<0){
+                throw new IllegalStateException();
+            }
+            cursor = lastRet;
+            LinkedList.this.remove(lastRet);
+            lastRet = -1;
+        }
+    }
 }
diff --git a/group18/1049843090/test/com/coding/basic/LinkedListTest.java b/group18/1049843090/test/com/coding/basic/LinkedListTest.java
@@ -115,4 +115,15 @@ public void removeLast() throws Exception {
 
     }
 
+    @Test
+    public void iterator() throws Exception {
+        Iterator iterator = linkedList.iterator();
+        assertEquals(false,iterator.hasNext());
+        linkedList.add("A");
+        assertEquals(true,iterator.hasNext());
+        assertEquals("A",iterator.next());
+        iterator.remove();
+        assertEquals(0,linkedList.size());
+    }
+
 }

Original file line number	Diff line number	Diff line change
`@@ -115,4 +115,15 @@ public void removeLast() throws Exception {`
`115`	`115`
`116`	`116`	`}`
`117`	`117`
	`118`	`+ @Test`
	`119`	`+ public void iterator() throws Exception {`
	`120`	`+ Iterator iterator = linkedList.iterator();`
	`121`	`+ assertEquals(false,iterator.hasNext());`
	`122`	`+ linkedList.add("A");`
	`123`	`+ assertEquals(true,iterator.hasNext());`
	`124`	`+ assertEquals("A",iterator.next());`
	`125`	`+ iterator.remove();`
	`126`	`+ assertEquals(0,linkedList.size());`
	`127`	`+ }`
	`128`	`+`
`118`	`129`	`}`