SetIterator Class

Article
04/11/2014

The SetIterator class allows you to iterate over the elements in a set.

Syntax

class SetIterator extends Object

Run On

Called

Methods

	Method	Description
	begin	Moves the iterator to the start of the set.
	cancelTimeOut	Cancels a previous method call to the setTimeOut method. (Inherited from Object.)
	definitionString	Returns a textual representation of the type of the iterator.
	delete	Removes the element that is pointed to by the iterator of the set.
	end	Moves the iterator past the last element in the set.
	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.)
	more	Determines whether the iterator denotes a valid set element.
	new	Creates a new iterator for a set. (Overrides the new Method.)
	next	Moves the iterator to the next element.
	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.)
	setTimeOut	Sets up the scheduled execution of a specified method. (Inherited from Object.)
	toString	Returns a textual representation of the current element in the set that is pointed to by the iterator. (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.)
	value	Retrieves the value that the iterator is pointing to.
	wait	Pauses a process. (Inherited from Object.)
	xml	Returns an XML string that represents the current object. (Inherited from Object.)

Top

Remarks

Set iterators may be viewed as pointers into the sets over which they iterate. Functionality is available to start the iteration, to determine whether more elements are available, and to fetch the element pointed to by the iterator.

Newly created set iterators are positioned at the first element in the set. The order in which the elements occur during iteration is defined not by the sequence in which the elements are inserted, but by the ordering of the elements. Elements with lower values appear before elements with higher values. The usual ordering for the types is used. If the constituent elements are objects; however, the addresses of the objects are used to supply the ordering. No specific ordering may consequently be inferred. The addresses of the objects are transient by nature.

It is best practice to use the class instead of the SetIterator class. This avoids problems if you are accessing the set on one tier with an iterator on another tier. Set iterators and the sets over which they iterate must be on the same client/server side. If you use SetIterator and code is marked as Called from, it is possible that the set and the iterator will end up on different tiers, and the code will fail. If you use SetEnumerator, the enumerator is automatically created on the same tier as the set. Also, to move to the next item in a set, you must explicitly call the more and next methods if you are using a set iterator. If you use SetEnumerator, you only have to call moveNext method.

Examples

The following example creates a set of integers and then adds four values to it. It then iterates through the set that is printing out information about each set element.

    Set s1 = new Set (Types::Integer); 
    int theElement; 
    SetIterator it; 
    ; 
  
    // Add some elements. 
    s1.add(3); 
    s1.add(4); 
    s1.add(13); 
    s1.add(1); 
  
    // Start a traversal of the elements in the set. 
    it = new SetIterator(s1); 
  
    // Prints "(begin)[1]". 
    print it.toString(); 
    // The elements are fetched in the order: 1, 3, 4, 13. 
    while (it.more()) 
    { 
        theElement = it.value(); 
        print theElement; 
  
         // Fetch the next element. 
        it.next(); 
    } 
    pause; 
}

Inheritance Hierarchy

Object Class
SetIterator Class
InventDimOnHandIterator Class

Share via