For loop

[Eleeist]

Hi,

I have an array "commands" containing two values. I want to compare "inputLine" to every value in the array and if there is a match - return "Command found: " + command message. But whatever value I pass into the method, the outputLine always stays null.

Why is this happening?

public class Processing {

    String[] commands = {"help", "start"};
    
    public String sortCommand(String inputLine) {
        
        String outputLine = null;
        
        for (int i = 0; i < commands.length; i++) {
        
            if (inputLine == commands[i]) {
                outputLine = "Command found: " + commands[i];
                break;
            }
        
        }
        
        return outputLine;

    }

}

[Shoss]

Have you tried verifying that whatever you're passing to the sortCommand function is what you think it is? I tried sortCommand("help") and it worked as you were expecting. Maybe check how you are getting your input.

[JosAH]

Don't compare Strings for equality with the == operator; use the equals(...) method instead; also read the API documentation for the String class.

kind regards,

Jos

[Eleeist]

@JosAH
Thanks, I corrected it to equals.

@Shoss
I think you are right. I tries to debug it myself but I still cannot find the source of this "null" value. Here is the code that sends "inputLine" to Processing.sortCommand():

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        
        Processing process = new Processing();
        
        outputLine = process.sortCommand(null);
        
        while ((inputLine = in.readLine()) != null) {
            
            out.println("->" + "\033[36m" + inputLine + "\033[0m");
            outputLine = process.sortCommand(inputLine);
            out.println(outputLine);
                    
        }

[Eleeist]

Problem solved, thanks for help.