Thursday 19 May 2011

Common methods in Vector API of Java

There are many useful methods in the Vector class and its parent classes. Here are some of the most useful. v is a Vector, i is an int index, o is an Object.
Method Description
v.add(o) adds Object o to Vector v
v.add(i, o) Inserts Object o at index i, shifting elements up as necessary.
v.clear() removes all elements from Vector v
v.contains(o) Returns true if Vector v contains Object o
v.firstElement(i) Returns the first element.
v.get(i) Returns the object at int index i.
v.lastElement(i) Returns the last element.
v.listIterator() Returns a ListIterator that can be used to go over the Vector. This is a useful alternative to the for loop.
v.remove(i) Removes the element at position i, and shifts all following elements down.
v.set(i,o) Sets the element at index i to o.
v.size() Returns the number of elements in Vector v.
v.toArray(Object[]) The array parameter can be any Object subclass (eg, String). This returns the vector values in that array (or a larger array if necessary). This is useful when you need the generality of a Vector for input, but need the speed of arrays when processing the data.

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