118 lines
3.6 KiB
Java
118 lines
3.6 KiB
Java
package protocolP2P;
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import protocolP2P.Payload;
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import tools.HostItem;
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import java.util.ArrayList;
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import java.util.List;
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import localException.InternalError;
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import localException.SizeError;
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import localException.ProtocolError;
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import localException.TransmissionError;
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import tools.BytesArrayTools;
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/** Representation of payload for discover response.
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* @author Louis Royer
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* @author Flavien Haas
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* @author JS Auge
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* @version 1.0
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*/
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public class DiscoverResponse extends Payload {
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private List<HostItem> hostList;
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private String filename;
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private static final int FILENAME_SIZE_POSITION = PAYLOAD_START_POSITION;
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private static final int FILENAME_POSITION = FILENAME_SIZE_POSITION + 4;
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/** Constructor with filename (typically used by tracker). If filename is null, it is initialized with "".
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* @param filename Name of the file related to the server list.
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* @param hostList List of servers
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* @throws InternalError
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*/
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public DiscoverResponse(String filename, List<HostItem> hostList) throws InternalError {
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super(RequestResponseCode.DISCOVER_RESPONSE);
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this.filename = filename;
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this.hostList = hostList;
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}
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/** Constructor (typically used by server) with a byte[] parameter containing the Packet received.
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* @param packet the full Packet received
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* @throws SizeError
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* @throws InternalError
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* @throws ProtocolError
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* @throws TransmissionError
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*/
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protected DiscoverResponse(byte[] packet) throws SizeError, ProtocolError, InternalError, TransmissionError {
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super(packet);
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int size = getPayloadSize(packet);
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/* Read filename size */
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int filenameSize = BytesArrayTools.readInt(packet, FILENAME_SIZE_POSITION);
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/* Read filename */
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filename = BytesArrayTools.readString(packet, FILENAME_POSITION, filenameSize);
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// TODO
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hostList = new ArrayList<>();
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int i = FILENAME_POSITION + filenameSize;
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while(i<size) {
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int port = BytesArrayTools.readInt16Bits(packet, i);
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i += 2;
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String hostname = BytesArrayTools.readString(packet, i, "\n");
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i += hostname.length();
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hostList.add(new HostItem(hostname, port));
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}
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}
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/** Returns a byte[] containing Packet with padding.
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* This Packet is still incomplete and should not be send directly.
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* ProtocolP2PPacket will use this method to generate the complete Packet.
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* @return Packet with padding
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* @throws InternalError
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*/
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protected byte[] toPacket() throws InternalError {
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int filenameSize = filename.length();
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int hostListSize = 0;
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for (HostItem hostItem: hostList) {
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hostListSize += (2 + hostItem.getHostname().length() + 1);
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}
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// compute total size
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int size = FILENAME_POSITION + filename.length() + hostListSize;
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byte[] packet = new byte[size + 1]; // java initialize all to zero
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// set request/response code
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packet[RequestResponseCode.RRCODE_POSITION] = requestResponseCode.codeValue;
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// set Payload size
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setPayloadSize(size - PAYLOAD_START_POSITION, packet);
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// write filename size
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BytesArrayTools.write(packet, FILENAME_SIZE_POSITION, filenameSize);
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// write filename
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BytesArrayTools.write(packet, filename, FILENAME_POSITION);
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int i = FILENAME_POSITION + filename.length();
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// write hostList
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for(HostItem hostItem: hostList) {
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try {
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BytesArrayTools.write16Bits(packet, i, hostItem.getPort());
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i+=2;
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String hostname = hostItem.getHostname() + "\n";
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BytesArrayTools.write(packet, hostname, i);
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i+=hostname.length();
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} catch (SizeError e) {
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throw new InternalError();
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}
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}
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return packet;
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}
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/** HostList getter.
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* @return hostList
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*/
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public List<HostItem> getHostList() {
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return hostList;
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}
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/** Filename getter.
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* @return filename
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*/
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public String getFilename() {
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return filename;
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}
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}
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