583: Highlights

• If you want to store instances, but you cannot predict how many there will be, then use a vector, rather than an array.
• If you want to implement a queue or a push-down stack, then use a vector.
• If you want to declare a vector variable and to create a vector instance, then instantiate the following pattern:

  Vector vector name = new Vector(); 
  

• If you want to add elements to the front or back of a vector, or to insert an element into a vector, then instantiate one of the following patterns:

  vector name.insertElementAt(instance, 0) 
  vector name.addElement(instance) 
  vector name.insertElementAt(instance, index) 
  

• If you want to retrieve an element from the front or back of a vector, then instantiate one of the following patterns:

  vector name.firstElement() 
  vector name.lastElement() 
  

• If you want to retrieve an element from a vector, or to replace an element in a vector as though that vector were an array, then instantiate one of the following patterns:

  vector name.elementAt(index) 
  vector name.setElementAt(index) 
  

• If you want to know how many elements a vector contains, then instantiate the following pattern:

  vector name.size() 
  

• If you want to use a vector element as a target for a method that belongs to a particular class, and that vector element is known to be an instance of the class, then cast the vector element to the class by instantiating the following pattern:

  ((class name) vector element) 
  

• If you want to perform a computation using every element of a vector in turn, then instantiate the following pattern:

  for (Iterator iterator variable = vector.iterator() 
       ; iterator variable.hasNext() 
       ;) {  
   ... iterator variable.next() ... 
   } 
  

• If you want to store int values in a vector, then wrap those values in Integer instances.