Question

I’m trying to write a method that will take a single character string and (if possible) return the virtual key code it corresponds to.

For instance:

private static int getKeyCode(final String key) {
    if(key.length != 1)
        throw new IllegalArgumentException("Only support single characters");

    // Also check to see if the 'key' is (1-9)(A-Z), otherwise exception

    // How to perform the conversion?
}

// Returns KeyEvent.VK_D
MyKeyUtils.getKeyCode("D");

Thus, passing MyKeyUtils.getKeyCode("blah") throws an IllegalArgumentException because “blah” has 4 chars. Also, passing MyKeyUtils.getKeyCode("@")throws the same exception because “@” is neither a digit 0-9 or a character A – Z.

Any ideas how to do the regex check as well as the actual conversion? Thanks in advance!

Answer 1

if (key.matches("[^1-9A-Z]"))
  throw new IllegalArgumentException("...");

---

Convertion can be done using (int) key.charAt(0) value, because:

public static final int VK_0 48 
public static final int VK_1 49 
...
public static final int VK_9 57 
public static final int VK_A 65 
...