NAs decoding

nas.java

import com.oss.nas1570.Nas1570 

import com.oss.nas1570.NASCoder;
import com.oss.nas1570.Nas1570;

import java.nio.ByteBuffer;

public class Test {
    public static void main(String[] args) throws Throwable {
        // NAS 2.0.0 - nasjava-r15.7.0

        Nas1570.initialize();
        NASCoder coder = Nas1570.getNASCoder();

        System.out.println(
                coder.decodeToJSON(
                        ByteBuffer.wrap(
                                decodeHexString("2741f768d52a720ec101081a06767a77617070066d6e63343830066d636333313104677072730d030000002672674a010a901b095d013030101b931f7196fefe7603ffff00fa00fa003205833401095e06fefee8e80505274d800003102607f1600010c00800ce000d000000030003102607f1600010c0020000000000000003000d04c6e22494000d04ac10c164802110030000108106c6e224948306ac10c1640010020594")
                        )
                )
        );


    }

    public static byte[] decodeHexString(String hexString) {
        if (hexString.length() % 2 == 1) {
            throw new IllegalArgumentException(
                    "Invalid hexadecimal String supplied.");
        }

        byte[] bytes = new byte[hexString.length() / 2];
        for (int i = 0; i < hexString.length(); i += 2) {
            bytes[i / 2] = hexToByte(hexString.substring(i, i + 2));
        }
        return bytes;
    }

    public static byte hexToByte(String hexString) {
        int firstDigit = toDigit(hexString.charAt(0));
        int secondDigit = toDigit(hexString.charAt(1));
        return (byte) ((firstDigit << 4) + secondDigit);
    }

    private static int toDigit(char hexChar) {
        int digit = Character.digit(hexChar, 16);
        if (digit == -1) {
            throw new IllegalArgumentException(
                    "Invalid Hexadecimal Character: " + hexChar);
        }
        return digit;
    }
}


/*
{
  "emmMessage":{
    "protected":{
      "protocolDiscriminator":7,
      "securityHeaderType":2,
      "mac":1106733269,
      "sequenceNumber":42,
      "message":"720EC101081A06767A77617070066D6E63343830066D636333313104677072730D030000002672674A010A901B095D013030101B931F7196FEFE7603FFFF00FA00FA003205833401095E06FEFEE8E80505274D800003102607F1600010C00800CE000D000000030003102607F1600010C0020000000000000003000D04C6E22494000D04AC10C164802110030000108106C6E224948306AC10C1640010020594"
    }
  }
}
*/