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  #1 (permalink)  
Old April 22nd, 2009, 10:18 PM
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Default Passing Data Using Data/Bye Streams

Hello Everyone!
First Let me say thanks for viewing this thread. Second I have been spending a week trying to reverse engineer this code to work and it has been driving me crazy. Basically, I set some variables of ints, shorts, and one ByteArray to place into an object, then into a ByteArrayOutputStream, then into a DataOutputStream. Then this data gets placed inside a datagram packet and I reverse engineer the code to get the original data out again. I hope that makes basic sense. My problem is the original variables that I am trying to get back I can get back my ints and shorts but I cannot get back my original ByteArray which contains a string. This program is a testdriver I need to work. I have included most of the code from the 2 primary classes. I thank you very much again!

//Test Driver Code
public class DriverClass {
static SignalPdu s = new SignalPdu();
static SignalPdu s2 = new SignalPdu();

static EntityID eid = new EntityID();
static byte pDatabyte[];
static String aString = "a";
static int id = 1;
static int encode = 2;
static int tdl = 6;
static int rate = 1;
static int radioId = 100;
static short dataLength = 100;
static int pDataLength = 100;
static ByteArrayOutputStream baos = new ByteArrayOutputStream();
static int encoder = 0;
public static void main(String[] args) {
TestDriver test = new TestDriver();


// Create PayLoad of A's in pDatabyte ByteArray
//for (int index = 0; index < 3; index++) {
//for (int index = 0; index < pDataLength; index++) {

aString = aString.concat(aString);
System.out.println("This is the new value of aString: " + aString);

aString = aString.concat("This is a test");

pDatabyte = aString.getBytes();
// aString.
System.out.println("This is the value of the bytearray pDatabyte: "
+ pDatabyte);
// }

// Prepare OutStream and Marshalling
DataOutputStream dos = new DataOutputStream(baos);

byte[] pduData = baos.toByteArray();

// Create Datagram Packet and Put byte data inside pDatabyte2
DatagramPacket packet = new DatagramPacket(pduData, pduData.length);

int pduDataLength = pduData.length;
System.out.println("The length of pduData is currently: " + pduDataLength);
for(int c = 0; c<pduDataLength; c++)
System.out.println("This is the value of pduData at : " + c + " " + pduData[c]);
//End of testing

byte[] pDatabyte2;
pDatabyte2 = packet.getData();

int pDatabyte2Length = pDatabyte2.length;
System.out.println("The length of pDatabyte2 is currently: " + pDatabyte2Length);
for(int j = 0; j<pDatabyte2Length; j++)
System.out.println("This is the value of pDatabyte2 at : " + j + " " + pDatabyte2[j]);
//End of Testing

// Create InputStream and prepare to unmarshal data
ByteArrayInputStream baos2 = new ByteArrayInputStream(pDatabyte2);
DataInputStream dis = new DataInputStream(baos2);

//If statements to test
// Test the Databyte--which is the onlyone that fails

if (s.getDatabyte() == s2.getDatabyte()) {
System.out.println("DataByte is the same");
} else {
System.out.println("DataByte is the (NOT)same");
System.out.println("This is the DataByte of s + s2: "
+ s.getDatabyte() + " " + s2.getDatabyte());

//Next Class
public class SignalPdu extends RadioCommunicationsFamilyPdu implements
Serializable {
/** encoding scheme used, and enumeration */
protected int encodingScheme;

/** tdl type */
protected int tdlType;

/** sample rate */
protected int sampleRate;

/** length od data */
protected short dataLength;

/** number of samples */
protected short samples;


public List data = new ArrayList();

protected byte pData[];

/** Constructor */
public SignalPdu() {


public int getMarshalledSize() {
int marshalSize = 0;

marshalSize = super.getMarshalledSize();
marshalSize = marshalSize + 2; // encodingScheme
marshalSize = marshalSize + 2; // tdlType
marshalSize = marshalSize + 4; // sampleRate
marshalSize = marshalSize + 2; // dataLength
marshalSize = marshalSize + 2; // samples
marshalSize = marshalSize + this.getDataLength(); // samples
for (int idx = 0; idx < pData.length; idx++) {
.println("****** <><><> This is before the getMarshallSize loop");

marshalSize = marshalSize + 1*8 ;

// OneByteChunk listElement = data.get(idx);
// marshalSize = marshalSize + listElement.getMarshalledSize();
.println("****** <><><> This is after the getMarshallSize loop");

return marshalSize;

public void setEncodingScheme(int pEncodingScheme) {
encodingScheme = pEncodingScheme;

public int getEncodingScheme() {
return encodingScheme;

public void setTdlType(int pTdlType) {
tdlType = pTdlType;

public int getTdlType() {
return tdlType;

public void setSampleRate(int pSampleRate) {
sampleRate = pSampleRate;

public int getSampleRate() {
return sampleRate;

public void setDataLength(short pDataLength) {
dataLength = pDataLength;

public short getDataLength() {
return dataLength;

// new code
public void setpDatabyte(byte pDatabyte[]) {
pData = pDatabyte;

public byte[] getDatabyte() {
return pData;

// end new code

public void setSamples(short pSamples) {
samples = pSamples;

public short getSamples() {
return samples;

public void setData(List pData1) {
.println("************* The setData method in SignalPdu is being called!!!");
data = pData1;

@XmlElementWrapper(name = "dataList")
public List getData() {
return data;

public void marshal(DataOutputStream dos) {

.println("**********%%%%%%%%%%% 1-2. This is the SignalPdu Class super.marshal(dos) method this is pData" + " " + pData);

String test;
byte dataByte[];
int marshalSize = 0;

try {

dos.writeShort((short) encodingScheme);
dos.writeShort((short) tdlType);
dos.writeInt((int) sampleRate);
dos.writeShort((short) dataLength);
dos.writeShort((short) samples);

.println("**********%%%%%%%%%%% 2-2. This is the SignalPdu Class super.marshal(dos) method ");

for (int idx1 = 0; idx1 < pData.length; idx1++) {


.println("**********%%%%%%%%%%% 3-2. This is the SignalPdu Class super.marshal(dos) method - This is value of dos "
+ dos);


catch (Exception e) {
//.println("**********%%%%%%%%%%% 4-2. This is the SignalPdu Class super.marshal(dos) method ");

} // end of marshal method

public void unmarshal(DataInputStream dis) {
.println("**********()()()()()() SignalPDU class, unmarshall method being called");
try {
encodingScheme = (int) dis.readUnsignedShort();
tdlType = (int) dis.readUnsignedShort();
System.out.println("c in the SignalPdu Class tdlType is equal to = " + tdlType);
sampleRate = dis.readInt();
dataLength = dis.readShort();
System.out.println("This is the unmarshall method of the signalpdu..... this is that datalength values: " + dataLength);
samples = dis.readShort();

String test2;
System.out.println("This is the unmarshalled method of the SignalPdu right before the loop");
for (int idx = 11; idx < pData.length; idx++) {

// dis.read
// test2 = dis.readUTF();

pData[idx] = dis.readByte();
System.out.println("&&&*** This is pData at unmarshal method of SignalPdu **&&&" + pData);
.println("This result is from the unmarshal method which accepts the DataInputStream dis looking for string: "

.println("This result is from the unmarshal method which accepts the DataInputStream dis:= "
+ pData[idx]);


} // end try
catch (Exception e) {
System.out.println("This is the unmarshalled method of the SignalPdu");
System.out.println("This is the unmarshalled method of the SignalPdu");

} // end of unmarshal method
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  #2 (permalink)  
Old April 23rd, 2009, 12:20 PM
Authorized User
Join Date: Feb 2009
Posts: 21
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Default Convert byte to bytearra[]

Hello Everyone!
I think I might have a solution to my own problem. The Output streams I do not think are letting me pass data that is not of primitive type. I was trying to pass a byte[] and it was coming up null everytime on the other end. My idea is to pass in a loop a bunch of bytes and then put them into a bytearray on the other side. To me it makes sense. I have had some issues trying to perform this conversion.

It is possible to convert several bytes into a byte[] array, correct?

Thanks a lot,
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