Practice converting user input strings like "FFTLR" into arrays of enum values using Java. This Java program uses an enum KivaCommands, nested loops, and error handling to map input characters to robot commands. Includes a full working example using Scanner, arrays, and IllegalArgumentException for invalid input. Ideal for mastering enums and control flow in Java.
Convert User Input to an Array of KivaCommands
The RemoteControl class currently takes in a String of commands from
the user that looks like "FFFTRF". However, our Kiva robots
cannot understand instructions in that form. They can simply make one
move at a time, accepting a single KivaCommand. So, we'll need to take
the user inputted commands and convert them into a more Kiva friendly
format, a list of KivaCommands that we can send to the robot's move
method one at a time.
Write the Convert Method Using continue and/or break
Create a helper method in the RemoteControl class called
convertToKivaCommands(). This method should take a String as a
parameter, which will be the commands that the user types into the
console (for example "FFFTRF"). It should return an array of
KivaCommands (in this case FORWARD, FORWARD, FORWARD, TAKE, TURN_RIGHT,
FORWARD). We recommend doing this by using the values() method of the
KivaCommand enum to get an array of all of the KivaCommands. You can
then use the getDirectionKey() method to determine which KivaCommand
each char in the String should be converted to. If the user enters a
character that does not correspond to a command throw an
IllegalArgumentException with a useful error message.
Note: When you want to print out the contents of a KivaCommand[] array
variable called commands, for example, you would call
Arrays.toString(commands) to turn the array into a single String. You'll
need to import java.util.Arrays to use this method. Here is some sample
code that you can play with in BlueJ to demonstrate this, then use the
approach for your needs:
Answer
import java.lang.Math;
import
java.util.Scanner;
import java.util.Arrays
;
public class
RemoteControl {
public KivaCommands[]
convertToKivaCommands(String parameter){
KivaCommands[]
GOTOORDERS = new KivaCommands[parameter.length()];
KivaCommands[]
DETERMINE = KivaCommands.values();
int i = 0;
for (char directionKey
: parameter.toCharArray()){
for (KivaCommands
command : DETERMINE){
if (directionKey ==
command.getDirectionKey()){
GOTOORDERS[i] =
command;
break;
}
}
if (GOTOORDERS[i] ==
null){
throw new
IllegalArgumentException("Character \'"+directionKey+"\' does
not correspond to a command!");
}
i++;
}
return GOTOORDERS;
}
}// end class
// enum
enum KivaCommands
{
FORWARD('F'),
TURN_LEFT('L'),
TURN_RIGHT('R'),
TAKE('T'),
DROP('D');
private char
action;
KivaCommands(char
directionKey)
{
action =
directionKey;
}
public char
getDirectionKey()
{
return action;
}
}// end enum
import java.lang.Math;
import
java.util.Scanner;
import java.util.Arrays
;
public class
RemoteControlTest {
public static void
main(String [] args){
// keyboard from
console
Scanner input = new
Scanner(System.in);
// instance object
class from RemoteControl
RemoteControl x = new RemoteControl();
System.out.print (
"Enter a String of commands : " );
String orders =
input.next();
// array of
KivaCommands with length of orders
KivaCommands
commands[] = new KivaCommands[orders.length()];
// calling method
commands =
x.convertToKivaCommands(orders);
System.out.print(Arrays.toString(commands
) );
}
}