vector methods and character input

[Sue Hellinger]

1. I have a class named 'node' and a vector made up of nodes. When I use a vector method like lastElement(), an Object is returned, not a node. However, I need a node to manipulate with as a result of this method call - for eg, I assign the node that I would like returned from the method to a newly created node. How do I tackle this?

2. How do I read character input from the console? i.e., objects of type 'char'?

Thanks.

[Tim McGuire]

In response to number 1, cast it as a Node:
if nodeVector is your vector,

(Node)nodeVector.getLastElement() will return a Node instead of an object

All java Collections work like this. (they pretend not to know what kind of objects they are holding and they make you tell them)

[Edwin Keeton]

Cast the Object type returned from lastElement() to a Node type.

A char is a standard type, not an Object or reference type. You can read them using an implementation of java.io.Reader.read() to read System.in. Like this:

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
char c = br.read();
// If you want to read a String instead of a single char
String s = br.readline();

[fred rosenberger]

If you are positive that only Nodes will be in the vector, Tim's solution is perfect. if there is ANY chance there might be something OTHER than a node in there, you may want to use the 'instanceOf' operator to make sure before you do your cast.

[Sue Hellinger]

Thanks much.

[Ernest Friedman-Hill]

If you're lucky enough to be using J2SE 5 (Tiger, aka JDK 1.5), you can use generics:

Vector<Node> myVector = new Vector<Node>();
myVector.add(new Node());
...
Node aNode = myVector.lastElement();

Note that here the cast is unnecessary!