Suppose you are writing a simple debug tool for your colleagues. To start with, you are going to provide 2 implementations - one writes the messages out to the command line (ConsoleTrace), while another writes them to a file (FileTrace). All you want your colleagues to know about the tool is
- The interface (or what my tool can do for you)
public interface Trace {
// turn on and off debugging
public void setDebug( boolean debug );
// write out a debug message
public void debug( String message );
// write out an error message
public void error( String message );
}
- How to choose a certain debugger by giving an argument to your main(String args[]) method. (for example, use “trace.log” to choose the FileTrace implementation or “console” for the ConsoleTrace debugger. You may want to add more implementations later as they need it. But they won't have to change any code to switch from one implementation to another. Design/write your debugging tool in Java.