deep iterator

deepIterator.java

@@ -0,0 +1,63 @@
+	//***************deep iterator***************
+	public static class NestedCollection implements Iterable<Object>{
+		List<Object> objs;
+
+		NestedCollection(List<Object> list){
+			objs = list;
+		}
+
+		@Override
+		public Iterator<Object> iterator() {
+			return new NestedIterator(objs);
+		}
+
+		private class NestedIterator implements Iterator<Object>{
+
+			private int index;
+			private List<Object> objs;
+			private Iterator<Object> curIterator;
+
+			NestedIterator(List<Object> objs){
+				index = 0;
+				this.objs = objs;
+			}
+
+			@Override
+			public boolean hasNext() {
+				if(index == objs.size())	return false;
+				Object obj = objs.get(index);
+				if(obj instanceof NestedCollection){
+					if(curIterator != null){
+						if(curIterator.hasNext()){
+							return true;
+						}else{
+							curIterator = null;
+							index++;
+							return this.hasNext();
+						}
+					}else{
+						curIterator = ((NestedCollection)obj).iterator();
+						return this.hasNext();
+					}
+				}else{
+					return true;
+				}
+			}
+
+			@Override
+			public Object next() {
+				if(this.hasNext()){
+					Object obj = objs.get(index);
+					if(obj instanceof NestedCollection){
+						return curIterator.next();
+					}else{
+						index++;
+						return obj;
+					}
+				}else{
+					throw new RuntimeException("No next element");
+				}
+			}
+
+		}
+	}