Add connection/handshake retry on same host

Author: mpv1989

ChangeLog

@@ -7,6 +7,7 @@ v4.2.2 (xxxx-xx-xx)
 * added ArangoDB.updateUserDefaultDatabaseAccess(String, Permissions)
 * added ArangoDB.updateUserDefaultCollectionAccess(String, Permissions)
 * added ArangoCollection.getDocuments(Collection<String>, Class)
+* added connection/handshake retry on same host
 
 v4.2.1 (2017-06-20)
 ---------------------------

src/main/java/com/arangodb/internal/DefaultHostHandler.java

@@ -31,13 +31,14 @@ public class DefaultHostHandler implements HostHandler {
 	private final List<Host> hosts;
 	private int current;
 	private int lastSuccess;
+	private int iterations;
 
 	/**
 	 * @param hosts
 	 */
 	public DefaultHostHandler(final List<Host> hosts) {
 		this.hosts = hosts;
-		current = lastSuccess = 0;
+		current = lastSuccess = iterations = 0;
 	}
 
 	@Override
@@ -50,8 +51,9 @@ public Host change() {
 		current++;
 		if ((current + 1) > hosts.size()) {
 			current -= hosts.size();
+			iterations++;
 		}
-		return current != lastSuccess ? get() : null;
+		return current != lastSuccess || iterations < 3 ? get() : null;
 	}
 
 	@Override

src/main/java/com/arangodb/internal/velocystream/internal/Connection.java

@@ -103,34 +103,35 @@ public synchronized void open() throws IOException {
 				}
 				socket.connect(new InetSocketAddress(host.getHost(), host.getPort()),
 					timeout != null ? timeout : ArangoDBConstants.DEFAULT_TIMEOUT);
+				socket.setKeepAlive(true);
+				socket.setTcpNoDelay(true);
+				if (LOGGER.isDebugEnabled()) {
+					LOGGER.debug(String.format("Connected to %s", socket));
+				}
+
+				outputStream = new BufferedOutputStream(socket.getOutputStream());
+				inputStream = socket.getInputStream();
+
+				if (useSsl != null && useSsl) {
+					if (LOGGER.isDebugEnabled()) {
+						LOGGER.debug(String.format("Start Handshake on %s", socket));
+					}
+					((SSLSocket) socket).startHandshake();
+				}
 				hostHandler.success();
 				break;
 			} catch (final IOException e) {
 				hostHandler.fail();
 				final Host failedHost = host;
 				host = hostHandler.change();
 				if (host != null) {
-					LOGGER.warn(String.format("Could not connect to %s. Try connecting to %s", failedHost, host));
+					LOGGER.warn(String.format("Could not connect to %s or SSL Handshake failed. Try connecting to %s",
+						failedHost, host));
 				} else {
 					throw e;
 				}
 			}
 		}
-		socket.setKeepAlive(true);
-		socket.setTcpNoDelay(true);
-		if (LOGGER.isDebugEnabled()) {
-			LOGGER.debug(String.format("Connected to %s", socket));
-		}
-
-		outputStream = new BufferedOutputStream(socket.getOutputStream());
-		inputStream = socket.getInputStream();
-
-		if (useSsl != null && useSsl) {
-			if (LOGGER.isDebugEnabled()) {
-				LOGGER.debug(String.format("Start Handshake on %s", socket));
-			}
-			((SSLSocket) socket).startHandshake();
-		}
 		sendProtocolHeader();
 		executor = Executors.newSingleThreadExecutor();
 		executor.submit(new Callable<Void>() {