Update protocol classes modelisation

src/exception/SizeError.java

@@ -0,0 +1,3 @@
+package exception;
+/** Used on reception side when size as set in datagram is too big, and we cant store this in a int/long as usual. */
+public class SizeError extends Exception {}

src/protocolP2P/FileList.java

@@ -31,10 +31,10 @@ public class FileList extends Payload {
 
 	/** Constructor (typically used by client) with a byte[] parameter containing the datagram received.
 	 * @param datagram	the full datagram received
-	 * @throws	ProtocolError
+	 * @throws	SizeError
 	 * @throws	InternalError
 	 */
-	public FileList(byte[] datagram) throws ProtocolError, InternalError {
+	protected FileList(byte[] datagram) throws SizeError, InternalError {
 		//TODO
 		/* assert to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) == RequestResponseCode.LIST_RESPONSE : "FileList subclass is incompatible with this datagram, request/response code must be checked before using this constructor";

src/protocolP2P/FilePart.java

@@ -39,19 +39,19 @@ public class FilePart extends Payload {
 
 	/** Constructor (typically used by client) with datagram received as parameter.
 	 * @param datagram	the full datagram received
-	 * @throws	ProtocolError
+	 * @throws	SizeError
 	 * @throws	InternalError
 	 */
-	public FilePart(byte[] datagram) throws ProtocolError, InternalError {
+	protected FilePart(byte[] datagram) throws SizeError, ProtocolError, InternalError {
 		/* assert to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) == RequestResponseCode.LOAD_RESPONSE : "FilePart subclass is incompatible with this datagram, request/response code must be checked before using this constructor";
 		/* InternalErrorException */
 		if (RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LOAD_RESPONSE) {
 			throw new InternalError();
 		}
-		setOffset(datagram); // this can throw ProtocolError
+		setOffset(datagram); // this can throw SizeError
-		setTotalFileSize(datagram); // this can throw ProtocolError
+		setTotalFileSize(datagram); // this can throw SizeError
-		int size = getPayloadSize(datagram); // this can throw ProtocolError
+		int size = getPayloadSize(datagram); // this can throw SizeError
 		int partialContentStart = setFilename(datagram, size) + 1; // this can throw ProtocolError
 		setPartialContent(datagram, partialContentStart, size);
 	}
@@ -61,7 +61,7 @@ public class FilePart extends Payload {
 	 * ProtocolP2PDatagram will use this method to generate the complete datagram.
 	 * @return datagram with padding
 	 */
-	public byte[] toDatagram() {
+	protected byte[] toDatagram() {
 		//TODO : calculate payload size
 		int size = ;
 		byte[] datagram = new byte[size]; // java initialize all to zero
@@ -76,16 +76,16 @@ public class FilePart extends Payload {
 		//TODO : write partialContent to datagram
 	}
 
-	private setOffset(byte[] datagram) throws ProtocolError {
+	private setOffset(byte[] datagram) throws SizeError {
 		//TODO: copy from 8 to 15 into long and write into offset.
 		// throw protocolerror if offset is < 0
 	}
-	private setTotalFileSize(byte[] datagram) throw ProtocolError {
+	private setTotalFileSize(byte[] datagram) throw SizeError {
 		// TODO: convert from byte 16 to 23 (included)
 		// into long and write into totalFileSize
 		// throw protocolerror if offset is < 0
 	}
-	private int setFilename(byte[] datagram, size) throws ProtocolError {
+	private int setFilename(byte[] datagram, int payloadSize) throws ProtocolError {
 		// TODO: copy datagram from byte 24 to the first \n (excluded)
 		// into filename unless we excess size
 		// (in this case the wrong size has been
@@ -93,7 +93,7 @@ public class FilePart extends Payload {
 		// return position of the \n
 		
 	}
-	private setPartialContent(byte[] datagram, int start, size) {
+	private setPartialContent(byte[] datagram, int start, int payloadSize) {
 		// TODO: copy datagram from start to size into partialContent
 	}
 

src/protocolP2P/Payload.java

@@ -33,7 +33,7 @@ public class Payload {
 	 * @throws	ProtocolError
 	 * @throws	InternalError
 	 */
-	public Payload(byte[] datagram) throws ProtocolError, InternalError {
+	protected Payload(byte[] datagram) throws ProtocolError, InternalError {
 		/* asserts to help debugging */
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LIST_RESPONSE : "LIST_RESPONSE must use FilePart class";
 		assert RequestResponseCode.fromCode(datagram[RequestResponseCode.RRCODE_POSITION]) != RequestResponseCode.LOAD_RESPONSE : "LOAD_RESPONSE must use FileList class";
@@ -56,7 +56,7 @@ public class Payload {
 	 * ProtocolP2PDatagram will use this method to generate the complete datagram.
 	 * @return datagram with padding
 	 */
-	public byte[] toDatagram() {
+	protected byte[] toDatagram() {
 		byte [] datagram = new byte[8]; // java initialize all to zero
 		// size is keep blank (ProtocolP2PDatagram will handle it)
 		// set request/response code
@@ -68,34 +68,35 @@ public class Payload {
 	/** Set payload’s size in a datagram.
 	 * @param size	integer representing payload size
 	 * @param datagram	datagram to be completed
-	 * @return	datagram with payload’s size set
 	 * @throws	InternalError
 	 */ 
-	protected static byte[] setPayloadSize(int size, byte[] datagram) throws InternalError {
+	protected static setPayloadSize(int size, byte[] datagram) throws InternalError {
 		/* assert to help debugging */
-		assert size >= 0: "Payload size cannont be negative";
+		assert size >= 0: "Payload size cannot be negative";
 		if (size < 0) {
+			// We don't throw SizeError
+			// because this is only for reception side
 			throw new InternalError();
 		}
 		for(int i=0;i<4;i++) {
 				datagram[Payload.PAYLOAD_SIZE_POSITON + i] = (byte) ((size >> (8 * (3 - i))) & 0xFF);
 		}
 	}
-		return datagram;
-	}
 
 	/** Get payload’s size from a datagram.
 	 * @param datagram	the full datagram received
 	 * @return	integer representing payload size
-	 * @throws	ProtocolError
+	 * @throws	SizeError
 	 */
-	protected static int getPayloadSize(byte[] datagram) throws ProtocolError {
+	protected static int getPayloadSize(byte[] datagram) throws SizeError {
 		int size = 0;
 		for(int i=0;i<4;i++) {
 			size |= ((int)datagram[PAYLOAD_SIZE_POSITON + i]) << (8* i);
 		}
 		if (size < 0) {
-			throw new ProtocolError();
+			// Size in datagram is probably correct
+			// but we cannot store it into a int (or this will be negative)
+			throw new SizeError();
 		}
 		return size;
 	}

src/protocolP2P/ProtocolP2PDatagram.java

@@ -5,6 +5,8 @@ import protocolP2P.Payload;
 import protocolP2P.RequestResponseCode;
 import java.util.ArrayList;
 import java.lang.Byte;
+import java.net.DatagramPacket;
+import java.net.DatagramSocket;
 
 /** Representation of datagram.
  * @author	Louis Royer
@@ -26,12 +28,37 @@ public class ProtocolP2PDatagram {
 		this.payload = payload;
 	}
 
-	/** Constructor with datagram as byte[] parameter (typically used when receiving datagram).
+	/** Send datagram on socket
+	 * @param socket	DatagramSocket used to send datagram
+	 */
+	public void send(DatagramSocket socket) {
+		//TODO
+		byte[] datagram = toDatagram();
+		// generate DatagramPacket
+		// send it
+	}
+
+	/** Receive datagram on socket
+	 * @param socket	DatagramSocket used to receive datagram
+	 * @return	payload of the datagram
+	 * @throws	ProtocolError
+	 * @throws	VersionError
+	 */
+	public static Payload receive(DatagramSocket socket) throws ProtocolError, VersionError {
+		//TODO
+		// reception
+		//datagram =
+		// contruction
+		ProtocolP2PDatagram p = new ProtocolP2PDatagram(datagram);
+		return p.getPayload();
+
+	}
+	/** Private constructor with datagram as byte[] parameter (typically used when receiving datagram).
 	 * @param datagram	the full datagram received
 	 * @throws	ProtocolError
 	 * @throws	VersionError
 	 */
-	public ProtocolP2PDatagram(byte[] datagram) throws ProtocolError, VersionError {
+	private ProtocolP2PDatagram(byte[] datagram) throws ProtocolError, VersionError, SizeError {
 		// unwrap version
 		version = datagram[VERSION_POSITON];
 		checkProtocolVersion(); // this can throw VersionError
@@ -53,7 +80,7 @@ public class ProtocolP2PDatagram {
 	 * This datagram is still complete and ready to be send.
 	 * @return the full datagram to send
 	 */
-	public byte[] toDatagram() {
+	private byte[] toDatagram() {
 		byte[] datagram = payload.toDatagram();
 		datagram[VERSION_POSITON] = version;
 		return datagram;
@@ -62,7 +89,7 @@ public class ProtocolP2PDatagram {
 	/** Returns Payload associated with the datagram.
 	 * @return	payload associated with the datagram
 	 */
-	public Payload getPayload() {
+	private Payload getPayload() {
 		return payload;
 	}