{"id":1204,"date":"2016-03-21T14:28:15","date_gmt":"2016-03-21T14:28:15","guid":{"rendered":"http:\/\/abhiandroid.com\/java\/?page_id=1204"},"modified":"2016-03-21T14:28:15","modified_gmt":"2016-03-21T14:28:15","slug":"listiterator","status":"publish","type":"page","link":"https:\/\/abhiandroid.com\/java\/listiterator","title":{"rendered":"ListIterator In Java With Example"},"content":{"rendered":"

Iterator<\/a>, as we have discussed in earlier topic is for traversing the collection objects and access the elements of\u00a0 that collection. Basically Iterator is for both List Interface and set Interface.<\/p>\n

Now we have a special type of Iterator that is only for List Interface which is known as ListIterator. It is even better Iterator for a List containing more utility methods like getting index of elements and adding elements to the base object.<\/p>\n

Using ListIterator we can iterate in both the directions, in forward direction as well as backward direction.\u00a0<\/strong><\/p>\n

\n

Methods of ListIterator<\/strong><\/h4>\n

<\/u>1. void add(E e):<\/strong><\/span>
\nThis method inserts the specified element into the list.<\/p>\n

2. boolean hasNext():<\/strong><\/span>
\nThis method \u00a0returns true if this listIterator has more elements when traversing the list in the forward direction.<\/p>\n

3. boolean hasPrevious():<\/strong><\/span>
\nThis method \u00a0returns true if this listIterator has more elements when traversing the list in the backward direction.<\/p>\n

4. E next():<\/strong><\/span>
\nThis method returns the next element in the list and advances the cursor position one step further.<\/p>\n

5. int nextIndex():<\/strong><\/span>
\nThis method returns the index of the element that would be returned by a subsequent call to next() method.<\/p>\n

6. E previous():<\/strong><\/span>
\nThis method returns the previous element in the list and moves the cursor position backwards direction.<\/p>\n

7. int previousIndex():<\/strong><\/span>
\nThis method returns the index of the element that would be returned by a subsequent call to previous() method.<\/p>\n

8. void remove():<\/strong><\/span>
\nThis method removes from the list the last element that was returned by next() method or previous() method.<\/p>\n

9. void set(E e):<\/strong><\/span>
\nThis method replaces the last element returned by next() method or previous() method with the specified element in the argument list<\/p>\n

\n

Example of List Iterator<\/strong><\/h4>\n

Let us discuss ListIterator with List Implementation with the help of program, following program has been divided into 5 Steps that we will discuss one by one<\/p>\n

import java.util.ArrayList;\r\nimport java.util.List;\r\nimport java.util.ListIterator;\r\n\r\npublic class ListIteratorDemo {\r\npublic static void main(String a[]){\r\n\r\n\/\/Step 1: Object of ArrayList is Created of String Type\r\nList<String> arrayListObj = new ArrayList<String>();\r\n\r\n\/\/Step 2 : Elements are added in the array list\r\n\r\narrayListObj.add(\"This\");\r\narrayListObj.add(\"is\");\r\narrayListObj.add(\"Example\");\r\narrayListObj.add(\"of\");\r\narrayListObj.add(\"ListIterator\");\r\n\r\n\/\/Step 3: Obtaining list iterator of type String\r\nListIterator<String> litr =arrayListObj.listIterator();\r\n\r\n\/\/Step 4: Traversing in Forward Direction\r\n\r\nSystem.out.println(\"Traversing the list in forward direction:\");\r\nwhile(litr.hasNext()){\r\nSystem.out.println(litr.next());\r\n}\r\n\r\n\/\/Step 5: Traversing in Backward Direction\r\nSystem.out.println(\"\\nTraversing the list in backward direction:\");\r\nwhile(litr.hasPrevious()){\r\nSystem.out.println(litr.previous());\r\n}\r\n}\r\n}\r\n<\/pre>\n
Output:<\/strong><\/span><\/p>\n
Traversing the list in forward direction:\r\n\r\nThis\r\nis\r\nExample\r\nof\r\nListIterator\r\n\r\nTraversing the list in backward direction:\r\n\r\nListIterator\r\nof\r\nExample\r\nis\r\nThis\u00a0\r\n<\/pre>\n
Description of Example:<\/strong><\/span><\/p>\n