Gcode to cartesian

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package fromgcodetocartesian;

import static com.sun.xml.internal.bind.v2.schemagen.Util.equal;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

/**
 *
 * @author sirine
 */
public class FromGcodeToCartesian {

    /**
    * @param args the command line arguments
    */
    static void getCartesian(String expression_Initiale){
        if(equal(expression_Initiale.substring(0,3),"G01")
                ||equal(expression_Initiale.substring(0,3),"G02")
                ||equal(expression_Initiale.substring(0,3),"G03")
                ||equal(expression_Initiale.substring(0,3),"G04")){
            if(expression_Initiale.charAt(4)=='X'||expression_Initiale.charAt(4)=='Y'){
                String X = expression_Initiale.substring(5,10);
                Double XPrime = Double.parseDouble(X);
                String Y = expression_Initiale.substring(12,17);
                Double YPrime = Double.parseDouble(Y);
                System.out.println("(X="+XPrime+",Y="+YPrime+")");
                //Create the point and add it to the object
    }}
}
    public static void main(String[] args) {
        // TODO code application logic here
        BufferedReader reader;
        try{
            reader=new BufferedReader(new FileReader("/Users/apple/Desktop/IP.txt"));
            String line = reader.readLine();
            while(line!=null){
                getCartesian(line);
                //read the next line
                line = reader.readLine();
            }
            reader.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}