Re: Alternative to if...else for keyword based actions
On Mon, 04 Aug 2008 11:31:02 -0700, <c0balt279@gmail.com> wrote:
[...]
How can I override the condition check and directly call a method
based on a string name of the method?? I'm trying to create a program
that reads a notepad source file and executes a program based on it.
Having all of these if...else checks was really getting annoying. Help?
There are probably lots of possible solutions. One obvious one would be
to use a Map instance to store the key and an instance implementing an
interface that can be called. You'd look up the interface instance by the
key, and then just call the method on that interface.
For example:
interface Operator
{
public void operator(String parameter);
}
Then (initializing your Map once somewhere):
Map<String, Operator> map = new HashMap<String, Operator>();
map.put("print", new Operator() { public void operator(String
parameter) { println(parameter); } });
map.put("add", new Operator() { public void operator(String parameter)
{ add(parameter); } });
// etc.
Then when you want to actually process the token:
Operator op = map.get(token);
op.operator(parameter);
Note the use of anonymous classes to implement the Operator interface for
each token. The only difference between each line is the key passed to
the Map.put() method, and the method called within the anonymous class
instantiated for that key.
Pete