[DE-528] non-blocking acquireHostList

core/src/main/java/com/arangodb/ArangoDB.java

@@ -22,6 +22,7 @@
 
 import com.arangodb.entity.*;
 import com.arangodb.internal.ArangoDBImpl;
+import com.arangodb.internal.ArangoExecutorSync;
 import com.arangodb.internal.InternalArangoDBBuilder;
 import com.arangodb.internal.net.*;
 import com.arangodb.model.*;
@@ -363,10 +364,13 @@ public ArangoDB build() {
             HostHandler hostHandler = createHostHandler(hostResolver);
             hostHandler.setJwt(config.getJwt());
 
+            CommunicationProtocol protocol = protocolProvider.createProtocol(config, hostHandler);
+            ArangoExecutorSync executor = new ArangoExecutorSync(protocol, config);
+            hostResolver.init(executor, config.getInternalSerde());
+
             return new ArangoDBImpl(
                     config,
-                    hostResolver,
-                    protocolProvider,
+                    protocol,
                     hostHandler
             );
         }

core/src/main/java/com/arangodb/ArangoDBException.java

@@ -39,7 +39,7 @@ public ArangoDBException(final ErrorEntity errorEntity) {
         super(String.format("Response: %s, Error: %s - %s", errorEntity.getCode(), errorEntity.getErrorNum(),
                 errorEntity.getErrorMessage()));
         this.entity = errorEntity;
-        this.responseCode = null;
+        this.responseCode = errorEntity.getCode();
         this.requestId = null;
     }
 
@@ -117,6 +117,9 @@ public static ArangoDBException of(Throwable t, Long requestId) {
 
     private static ArangoDBException of(String message, Throwable t, Long requestId) {
         Objects.requireNonNull(t);
+        if (t instanceof CompletionException) {
+            return of(message, t.getCause(), requestId);
+        }
         Throwable cause = unwrapCause(t);
         String msg = message != null ? message
                 : t.getMessage() != null ? t.getMessage()
@@ -141,7 +144,7 @@ private static ArangoDBException of(String message, Throwable t, Long requestId)
     }
 
     private static Throwable unwrapCause(Throwable t) {
-        if (t instanceof ArangoDBException || t instanceof CompletionException) {
+        if (t instanceof ArangoDBException) {
             return unwrapCause(t.getCause());
         }
         return t;

core/src/main/java/com/arangodb/internal/ArangoDBImpl.java

@@ -23,9 +23,8 @@
 import com.arangodb.*;
 import com.arangodb.entity.*;
 import com.arangodb.internal.config.ArangoConfig;
+import com.arangodb.internal.net.CommunicationProtocol;
 import com.arangodb.internal.net.HostHandler;
-import com.arangodb.internal.net.HostResolver;
-import com.arangodb.internal.net.ProtocolProvider;
 import com.arangodb.internal.serde.SerdeUtils;
 import com.arangodb.model.*;
 import org.slf4j.Logger;
@@ -44,11 +43,10 @@ public class ArangoDBImpl extends InternalArangoDB implements ArangoDB {
     private final HostHandler hostHandler;
 
     public ArangoDBImpl(final ArangoConfig config,
-                        final HostResolver hostResolver, final ProtocolProvider protocolProvider,
+                        final CommunicationProtocol protocol,
                         final HostHandler hostHandler) {
-        super(protocolProvider.createProtocol(config, hostHandler), config, config.getInternalSerde());
+        super(protocol, config);
         this.hostHandler = hostHandler;
-        hostResolver.init(executorSync(), getSerde());
         LOGGER.debug("ArangoDB Client is ready to use");
     }
 

core/src/main/java/com/arangodb/internal/ArangoExecuteable.java

@@ -37,10 +37,8 @@ public abstract class ArangoExecuteable implements ArangoSerdeAccessor {
     private final ArangoExecutorAsync executorAsync;
     private final InternalSerde serde;
 
-    protected ArangoExecuteable(final CommunicationProtocol protocol,
-                                final ArangoConfig config,
-                                final InternalSerde serde) {
-        this(new ArangoExecutorSync(protocol, config), new ArangoExecutorAsync(protocol, config), serde);
+    protected ArangoExecuteable(final CommunicationProtocol protocol, final ArangoConfig config) {
+        this(new ArangoExecutorSync(protocol, config), new ArangoExecutorAsync(protocol, config), config.getInternalSerde());
     }
 
     protected ArangoExecuteable(final ArangoExecuteable other) {

core/src/main/java/com/arangodb/internal/InternalArangoDB.java

@@ -50,8 +50,8 @@ public abstract class InternalArangoDB extends ArangoExecuteable {
     private static final String PATH_API_USER = "/_api/user";
     private static final String PATH_API_QUERY_RULES = "/_api/query/rules";
 
-    protected InternalArangoDB(final CommunicationProtocol protocol, final ArangoConfig config, final InternalSerde util) {
-        super(protocol, config, util);
+    protected InternalArangoDB(final CommunicationProtocol protocol, final ArangoConfig config) {
+        super(protocol, config);
     }
 
     protected InternalArangoDB(final ArangoExecuteable other) {

core/src/main/java/com/arangodb/internal/InternalArangoDBBuilder.java

@@ -337,10 +337,9 @@ protected HostResolver createHostResolver(final Collection<Host> hosts, final Co
             LOG.debug("Use SimpleHostResolver");
             return new SimpleHostResolver(new ArrayList<>(hosts));
         }
-
     }
 
-    protected <C extends Connection> Collection<Host> createHostList(final ConnectionFactory connectionFactory) {
+    protected Collection<Host> createHostList(final ConnectionFactory connectionFactory) {
         final Collection<Host> hostList = new ArrayList<>();
         for (final HostDescription host : config.getHosts()) {
             hostList.add(HostUtils.createHost(host, config, connectionFactory));

core/src/main/java/com/arangodb/internal/net/DirtyReadHostHandler.java

@@ -72,27 +72,12 @@ public void reset() {
         determineHostHandler().reset();
     }
 
-    @Override
-    public void confirm() {
-        determineHostHandler().confirm();
-    }
-
     @Override
     public void close() throws IOException {
         master.close();
         follower.close();
     }
 
-    @Override
-    public void closeCurrentOnError() {
-        determineHostHandler().closeCurrentOnError();
-    }
-
-    @Override
-    public void closeCurrentOnErrorIfNotMatch(HostDescription host) {
-        determineHostHandler().closeCurrentOnErrorIfNotMatch(host);
-    }
-
     @Override
     public void setJwt(String jwt) {
         master.setJwt(jwt);

core/src/main/java/com/arangodb/internal/net/ExtendedHostResolver.java

@@ -33,6 +33,10 @@
 import org.slf4j.LoggerFactory;
 
 import java.util.*;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
 
 import static com.arangodb.internal.serde.SerdeUtils.constructParametricType;
 
@@ -48,10 +52,10 @@ public class ExtendedHostResolver implements HostResolver {
     private final ArangoConfig config;
     private final ConnectionFactory connectionFactory;
     private final Integer acquireHostListInterval;
-    private long lastUpdate;
+    private final ScheduledExecutorService scheduler;
     private ArangoExecutorSync executor;
     private InternalSerde arangoSerialization;
-
+    private ScheduledFuture<?> schedule;
 
     public ExtendedHostResolver(final List<Host> hosts, final ArangoConfig config,
                                 final ConnectionFactory connectionFactory, Integer acquireHostListInterval) {
@@ -61,22 +65,34 @@ public ExtendedHostResolver(final List<Host> hosts, final ArangoConfig config,
         this.config = config;
         this.connectionFactory = connectionFactory;
 
-        lastUpdate = 0;
+        scheduler = Executors.newSingleThreadScheduledExecutor(r -> {
+                    Thread t = Executors.defaultThreadFactory().newThread(r);
+                    t.setDaemon(true);
+                    return t;
+                }
+        );
     }
 
     @Override
     public void init(ArangoExecutorSync executor, InternalSerde arangoSerialization) {
         this.executor = executor;
         this.arangoSerialization = arangoSerialization;
+        resolve();
+        schedule = scheduler.scheduleAtFixedRate(this::resolve, acquireHostListInterval, acquireHostListInterval, TimeUnit.MILLISECONDS);
     }
 
     @Override
-    public HostSet resolve(boolean initial, boolean closeConnections) {
-
-        if (!initial && isExpired()) {
+    public void close() {
+        schedule.cancel(false);
+        scheduler.shutdown();
+    }
 
-            lastUpdate = System.currentTimeMillis();
+    @Override
+    public HostSet getHosts() {
+        return hosts;
+    }
 
+    private void resolve() {
             final Collection<String> endpoints = resolveFromServer();
             if (LOGGER.isDebugEnabled()) {
                 LOGGER.debug("Resolve {} Endpoints", endpoints.size());
@@ -110,17 +126,11 @@ public HostSet resolve(boolean initial, boolean closeConnections) {
                 }
             }
             hosts.clearAllMarkedForDeletion();
-        }
-
-        return hosts;
     }
 
     private Collection<String> resolveFromServer() {
-
         Collection<String> response;
-
         try {
-
             response = executor.execute(
                     new InternalRequest(ArangoRequestParam.SYSTEM, RequestType.GET, "/_api/cluster/endpoints"),
                     response1 -> {
@@ -136,7 +146,6 @@ private Collection<String> resolveFromServer() {
                     }, null);
         } catch (final ArangoDBException e) {
             final Integer responseCode = e.getResponseCode();
-
             // responseCode == 403: single server < 3.7
             // responseCode == 501: single server >= 3.7
             if (responseCode != null && (responseCode == 403 || responseCode == 501)) {
@@ -145,12 +154,6 @@ private Collection<String> resolveFromServer() {
                 throw e;
             }
         }
-
         return response;
     }
-
-    private boolean isExpired() {
-        return System.currentTimeMillis() > (lastUpdate + acquireHostListInterval);
-    }
-
 }

core/src/main/java/com/arangodb/internal/net/FallbackHostHandler.java

@@ -37,16 +37,14 @@ public class FallbackHostHandler implements HostHandler {
     private Host current;
     private Host lastSuccess;
     private int iterations;
-    private boolean firstOpened;
     private HostSet hosts;
 
     public FallbackHostHandler(final HostResolver resolver) {
         this.resolver = resolver;
         lastFailExceptions = new ArrayList<>();
         reset();
-        hosts = resolver.resolve(true, false);
+        hosts = resolver.getHosts();
         current = lastSuccess = hosts.getHostsList().get(0);
-        firstOpened = true;
     }
 
     @Override
@@ -69,7 +67,7 @@ public void success() {
 
     @Override
     public void fail(Exception exception) {
-        hosts = resolver.resolve(false, false);
+        hosts = resolver.getHosts();
         final List<Host> hostList = hosts.getHostsList();
         final int index = hostList.indexOf(current) + 1;
         final boolean inBound = index < hostList.size();
@@ -93,30 +91,10 @@ public void reset() {
         lastFailExceptions.clear();
     }
 
-    @Override
-    public void confirm() {
-        if (firstOpened) {
-            // after first successful established connection, update host list
-            hosts = resolver.resolve(false, false);
-            firstOpened = false;
-        }
-    }
-
     @Override
     public void close() {
         hosts.close();
-    }
-
-    @Override
-    public void closeCurrentOnError() {
-        current.closeOnError();
-    }
-
-    @Override
-    public synchronized void closeCurrentOnErrorIfNotMatch(HostDescription host) {
-        if (!host.equals(current.getDescription())) {
-            closeCurrentOnError();
-        }
+        resolver.close();
     }
 
     @Override

core/src/main/java/com/arangodb/internal/net/HostHandler.java

@@ -39,14 +39,8 @@ public interface HostHandler {
 
     void reset();
 
-    void confirm();
-
     void close() throws IOException;
 
-    void closeCurrentOnError();
-
-    void closeCurrentOnErrorIfNotMatch(HostDescription host);
-
     void setJwt(String jwt);
 
 }

core/src/main/java/com/arangodb/internal/net/HostResolver.java

@@ -28,8 +28,12 @@
  */
 public interface HostResolver {
 
-    void init(ArangoExecutorSync executorSync, InternalSerde arangoSerialization);
+    default void init(ArangoExecutorSync executorSync, InternalSerde arangoSerialization) {
+    }
 
-    HostSet resolve(boolean initial, boolean closeConnections);
+    default void close() {
+    }
+
+    HostSet getHosts();
 
 }

core/src/main/java/com/arangodb/internal/net/RandomHostHandler.java

@@ -39,13 +39,15 @@ public RandomHostHandler(final HostResolver resolver, final HostHandler fallback
         super();
         this.resolver = resolver;
         this.fallback = fallback;
-        current = getRandomHost(true, false);
+        hosts = resolver.getHosts();
+        current = getRandomHost();
     }
 
     @Override
     public Host get(final HostHandle hostHandle, AccessType accessType) {
         if (current == null) {
-            current = getRandomHost(false, true);
+            hosts = resolver.getHosts();
+            current = getRandomHost();
         }
         return current;
     }
@@ -68,8 +70,7 @@ public synchronized void failIfNotMatch(HostDescription host, Exception exceptio
         }
     }
 
-    private Host getRandomHost(final boolean initial, final boolean closeConnections) {
-        hosts = resolver.resolve(initial, closeConnections);
+    private Host getRandomHost() {
         final ArrayList<Host> hostList = new ArrayList<>(hosts.getHostsList());
         Collections.shuffle(hostList);
         return hostList.get(0);
@@ -80,25 +81,10 @@ public void reset() {
         fallback.reset();
     }
 
-    @Override
-    public void confirm() {
-    }
-
     @Override
     public void close() {
         hosts.close();
-    }
-
-    @Override
-    public void closeCurrentOnError() {
-        current.closeOnError();
-    }
-
-    @Override
-    public synchronized void closeCurrentOnErrorIfNotMatch(HostDescription host) {
-        if (!host.equals(current.getDescription())) {
-            closeCurrentOnError();
-        }
+        resolver.close();
     }
 
     @Override