Created AC35 Streaming server

- Sends heartbeat messages every 5 seconds - Sends XML at beginning Tags: #story[29]
2026-05-09 14:28:43 +00:00 · 2017-04-19 19:05:19 +12:00
parent 34872a822b
commit edc306da22
12 changed files with 783 additions and 0 deletions
@@ -0,0 +1,96 @@
+package seng302.server.messages;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.zip.CRC32;
+
+public class XMLMessage extends Message{
+    private final MessageType MESSAGE_TYPE = MessageType.XML_MESSAGE;
+    private final int MESSAGE_VERSION = 1; //Always set to 1
+    private final int MESSAGE_SIZE = 14;
+
+    // Message fields
+    private int timeStamp;
+    private short ack = 0x00; //Unused
+    private XMLMessageSubType xmlMessageSubType;
+    private Short length;
+    private Short sequence;
+    private String content;
+    private CRC32 crc;
+
+    /**
+     * XML Message from the AC35 Streaming data spec
+     * @param content The XML content
+     * @param type The XML Message Sub Type
+     */
+    public XMLMessage(String content, XMLMessageSubType type, short sequenceNum){
+        this.content = content;
+        this.xmlMessageSubType = type;
+        crc = new CRC32();
+        timeStamp = (int) (System.currentTimeMillis() / 1000L);
+        ack = 0;
+        length = (short) this.content.length();
+        sequence = sequenceNum;
+
+        setHeader(new Header(MESSAGE_TYPE, 0x01, (short) getSize()));
+    }
+
+    /**
+     * @return The length of this message
+     */
+    public int getSize(){
+        return MESSAGE_SIZE + content.length();
+    }
+
+    /**
+     * Send this message as a stream of bytes
+     * @param outputStream The output stream to send the message
+     */
+    public void send(DataOutputStream outputStream) {
+        ByteBuffer buff = ByteBuffer.allocate(Header.getSize() + getSize() + 4);
+        buff.put(getHeader().getByteBuffer());
+        buff.position(Header.getSize());
+
+        // Version Number, 1 byte
+        buff.put(ByteBuffer.allocate(1).put((byte)MESSAGE_VERSION).array());
+        buff.position(Header.getSize() + 1);
+
+        // Ack, 2 bytes
+        buff.put(ByteBuffer.allocate(2).putShort(ack).array());
+        buff.position(Header.getSize() + 3);
+
+        // Timestamp, 6 bytes
+        buff.put(ByteBuffer.allocate(6).putInt(timeStamp).array());
+        buff.position(Header.getSize() + 9);
+
+        // XML message sub type, 1 byte
+        buff.put(ByteBuffer.allocate(1).put((byte)xmlMessageSubType.getType()).array());
+        buff.position(Header.getSize() + 10);
+
+        // Seq num, 2 bytes
+        buff.put(ByteBuffer.allocate(2).putShort(sequence).array());
+        buff.position(Header.getSize() + 12);
+
+        // Message length, 2 bytes
+        buff.put(ByteBuffer.allocate(2).putShort(length).array());
+        buff.position(Header.getSize() + 14);
+
+        // XML Content
+        buff.put(this.content.getBytes());
+        buff.position(Header.getSize() + 14 + this.content.getBytes().length);
+
+        // calculate CRC
+        crc.update(buff.array());
+
+        // Add CRC to message
+        buff.put(ByteBuffer.allocate(4).putInt((short)crc.getValue()).array());
+
+        // Send
+        try {
+            outputStream.write(buff.array());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}