ListEnumerator Class

Article
04/11/2014

The ListEnumerator class lets you traverse the elements in a list.

Syntax

class ListEnumerator extends Object implements Enumerator

Run On

Called

Methods

	Method	Description
	cancelTimeOut	Cancels a previous method call to the setTimeOut method. (Inherited from Object.)
	current	Retrieves the value that is pointed to by the enumerator.
	definitionString	Returns a description of the enumerator.
	equal	Determines whether the specified object is equal to the current one. (Inherited from Object.)
	getTimeOutTimerHandle	Returns the timer handle for the object. (Inherited from Object.)
	handle	Retrieves the handle of the class of the object. (Inherited from Object.)
	moveNext	Determines whether the enumerator denotes a valid list element.
	new	Initializes a new instance of the Object class. (Inherited from Object.)
	notify	Releases the hold on an object that has called the wait method on this object. (Inherited from Object.)
	notifyAll	Releases a lock on the object that was issued by the wait method on this object. (Inherited from Object.)
	objectOnServer	Determines whether the object is on a server. (Inherited from Object.)
	owner	Returns the instance that owns the object. (Inherited from Object.)
	reset	Moves the enumerator to the start of the list.
	setTimeOut	Sets up the scheduled execution of a specified method. (Inherited from Object.)
	toString	Returns a description of the content of the element in the list that the enumerator is currently pointing to. (Overrides the toString Method.)
	usageCount	Returns the current number of references, that is, the value of the reference counter, that the object has. (Inherited from Object.)
	wait	Pauses a process. (Inherited from Object.)
	xml	Returns an XML string that represents the current object. (Inherited from Object.)

Top

Remarks

List enumerators start before the first element in the list. You must call the ListEnumerator.moveNext method to make it point to the first element in the list.

It is best practice to use the ListEnumerator class instead of the ListIterator class, because enumerators are automatically created on the same tier as the list (when the list.getEnumerator method is called). This avoids a potential problem in code that is marked as Called from, where the iterator and list can be on separate tiers. In addition, list enumerators require less code than list iterators and therefore perform slightly better. The only situation where you have to use a list iterator is if you want to delete items from a list (use the ListIterator.delete method).

Examples

The following example creates a list of integers and puts some values into it. It then creates an enumerator, and then sets the enumerator to the first element in the list and then the second element in the list.

{ 
    List list = new List(Types::Integer); 
    ListEnumerator enumerator; 
  
    // Add some elements to the list 
    list.addEnd(1); 
    list.addEnd(2); 
    list.addStart(3); 
  
    // Set the enumerator 
    enumerator = list.getEnumerator(); 
 
    // Print a description of the list 
    print enumerator.definitionString(); 
 
    // Go to beginning of enumerator 
    enumerator.reset(); 
    //Go to the first element in the List 
    enumerator.moveNext(); 
  
    // Print contents of first and second elements 
    // First element is 3 as this was added to start of list 
    print enumerator.toString(); 
    enumerator.moveNext(); 
    print enumerator.toString(); 
    pause; 
}

Inheritance Hierarchy

Object Class
ListEnumerator Class