implement Torrent type to hold InfoHash and PeerSet

src/test/java/com/mykola2312/retracker/tracker/Torrent.java

@@ -0,0 +1,39 @@
+package com.mykola2312.retracker.tracker;
+
+import java.util.Collection;
+
+public class Torrent {
+	private InfoHash infoHash;
+	private PeerSet peers;
+	
+	public Torrent(InfoHash infoHash) {
+		this.infoHash = infoHash;
+		this.peers = new PeerSet();
+	}
+	
+	// will construct PeerSet with initial single peer
+	public Torrent(InfoHash infoHash, Peer initiator) {
+		this.infoHash = infoHash;
+		this.peers = new PeerSet(1);
+		peers.put(initiator);
+	}
+	
+	public InfoHash getInfoHash() {
+		return infoHash;
+	}
+	
+	/* Copy current set of peers into destination collection.
+	 * Copying over reference is preferable in concurrent environment
+	 */
+	public <T extends Collection<Peer>> void copyPeers(T dst) {
+		for (Peer peer : peers) {
+			dst.add(peer);
+		}
+	}
+	
+	public <T extends Collection<Peer>> void updatePeers(T src) {
+		for (Peer peer : src) {
+			peers.put(peer);
+		}
+	}
+}

src/test/java/com/mykola2312/retracker/tracker/TorrentTest.java

@@ -0,0 +1,44 @@
+package com.mykola2312.retracker.tracker;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+public class TorrentTest {
+	private static InetSocketAddress newAddress(String addr, int port) throws UnknownHostException {
+		return new InetSocketAddress(InetAddress.getByName(addr), port);
+	}
+	
+	@Test
+	public void testUpdatePeers() throws Exception {
+		final InfoHash infoHash = new InfoHash();
+		infoHash.fromString("360775c6629eb06e60d90201aed1b7bc49a1ce16");
+		
+		Torrent torrent = new Torrent(infoHash);
+		{
+			ArrayList<Peer> copy = new ArrayList<Peer>();
+			torrent.copyPeers(copy);
+			
+			assertEquals(0, copy.size());
+		}
+		
+		List<Peer> src = Arrays.asList(new Peer(newAddress("127.0.0.1", 1337)),
+										new Peer(newAddress("127.0.0.1", 1338)));
+		torrent.updatePeers(src);
+		{
+			ArrayList<Peer> copy = new ArrayList<Peer>();
+			torrent.copyPeers(copy);
+			
+			assertEquals(2, copy.size());
+			assertEquals(1337, copy.get(0).getAddress().getPort());
+			assertEquals(1338, copy.get(1).getAddress().getPort());
+		}
+	}
+}