Created AC35 Streaming server

- Sends heartbeat messages every 5 seconds
- Sends XML at beginning

Tags: #story[29]

src/main/java/seng302/server/messages/Heartbeat.java

@@ -0,0 +1,51 @@
+package seng302.server.messages;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.zip.CRC32;
+
+public class Heartbeat extends Message {
+    private final int MESSAGE_SIZE = 4;
+    private int seqNo;
+
+    /**
+     * Heartbeat from the AC35 Streaming data spec
+     * @param seqNo Increment every time a message is sent
+     */
+    public Heartbeat(int seqNo){
+        this.seqNo = seqNo;
+    }
+
+    @Override
+    public int getSize() {
+        return MESSAGE_SIZE;
+    }
+
+    @Override
+    public void send(DataOutputStream outputStream) {
+        setHeader(new Header(MessageType.HEARTBEAT, 0x01, (short) getSize()));
+
+        ByteBuffer buff = ByteBuffer.allocate(Header.getSize() + getSize() + getSize());
+
+        // Write header
+        buff.put(getHeader().getByteBuffer());
+        buff.position(Header.getSize());
+
+        // Write seq num
+        buff.put(ByteBuffer.allocate(4).putInt(seqNo).array());
+        buff.position(Header.getSize()+4);
+
+        // Write CRC
+        CRC32 crc = new CRC32();
+        crc.update(buff.array());
+
+        buff.put(ByteBuffer.allocate(4).putInt((short)crc.getValue()).array());
+
+        try {
+            outputStream.write(buff.array());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}