you cant switch a String?

[Justin Fox]

why can't I switch a java.lang.String object?

says i have to pass an integer?

anyway around this?

Justin
[ September 18, 2006: Message edited by: Bear Bibeault ]

[Jean-Francois Briere]

Use if else if instead.

[marc weber]

Or maybe look into using enums instead of Strings.

[Justin Fox]

ok, i used if else, but i have to look at input and decide if its a "special command" or not, then execute that special command.

Example:

#logoff
#sethost <hostname>
#setport <port>
etc...

i am extracting the input, and using substring to get the names and
seeing if its a command..

any easier way?

Justin

[Steve Fahlbusch]

Well,

You could put the key words in a dictionary (Hashmap in Java) and if it is a command, do command something - assuming that one command something is similar to another command something.

If every command is different (say like a compiler checking the input) and if you do not have a formal language to define it, then a series of if .. elses is probably the best way.

If the commands have a lot in common, put a dictionary with key:value where key is the command and value is an int value you can use for the switch.

-steve

[Ken Blair]

Originally posted by Steve Fahlbusch:
Well,

You could put the key words in a dictionary (Hashmap in Java) and if it is a command, do command something - assuming that one command something is similar to another command something.

If every command is different (say like a compiler checking the input) and if you do not have a formal language to define it, then a series of if .. elses is probably the best way.

If the commands have a lot in common, put a dictionary with key:value where key is the command and value is an int value you can use for the switch.

-steve

Or better yet, take that one step further and use Strategy instead of a switch. If you're going to be looking at the command as a String simply use that String as a key to map to a Command object or something similar. Then your code ends up looking something like this:

final Command cmd = commandRegistry.get(inputLine);
if (cmd != null) {
    cmd.execute();
} else {
    // Wasn't a command
}

Certainly preferable to a giant switch statement in my eyes. Has the benefit of being able to map a String to any Command, even changing it at runtime based upon a configuration file or Preferences.

[Justin Fox]

i will definately read up on this "strategy", but i got it working with
if\else, and I am too lazy to change it now lol...

thanks again,

Justin

[Rahul Bhattacharjee]

That is how the switch is suppose to work.These are java language constructs and if our program doesnot adhere to this then it would raise a
compile time error.

It is something like we cannot have a statement like

new String() = a String;

we need to write it as
String a = new String();

These are the java language constructs.