Avoid loading and looking up Locks factory for each database.

Extract factories for various locks construction from CommunityEditionModule.
Extract interface for LocksFactory into separate class.

community/kernel/src/main/java/org/neo4j/kernel/impl/locking/DynamicLocksFactory.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.impl.locking;
+
+import org.neo4j.helpers.Service;
+
+/**
+ * Factory for lock managers that can be loaded over service loading.
+ */
+public abstract class DynamicLocksFactory extends Service implements LocksFactory
+{
+    public DynamicLocksFactory( String key, String... altKeys )
+    {
+        super( key, altKeys );
+    }
+}

community/kernel/src/main/java/org/neo4j/kernel/impl/locking/Locks.java

@@ -19,11 +19,8 @@
  */
 package org.neo4j.kernel.impl.locking;
 
-import java.time.Clock;
 import java.util.stream.Stream;
 
-import org.neo4j.helpers.Service;
-import org.neo4j.kernel.configuration.Config;
 import org.neo4j.storageengine.api.lock.AcquireLockTimeoutException;
 import org.neo4j.storageengine.api.lock.LockTracer;
 import org.neo4j.storageengine.api.lock.ResourceLocker;
@@ -51,15 +48,6 @@
  */
 public interface Locks
 {
-    abstract class Factory extends Service
-    {
-        public Factory( String key, String... altKeys )
-        {
-            super( key, altKeys );
-        }
-
-        public abstract Locks newInstance( Config config, Clock clocks, ResourceType[] resourceTypes );
-    }
 
     /** For introspection and debugging. */
     interface Visitor

community/kernel/src/main/java/org/neo4j/kernel/impl/locking/LocksFactory.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.impl.locking;
+
+import java.time.Clock;
+
+import org.neo4j.kernel.configuration.Config;
+import org.neo4j.storageengine.api.lock.ResourceType;
+
+public interface LocksFactory
+{
+    Locks newInstance( Config config, Clock clock, ResourceType[] resourceTypes );
+}

community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/CommunityLocksFactory.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.impl.locking.community;
+
+import java.time.Clock;
+
+import org.neo4j.kernel.configuration.Config;
+import org.neo4j.kernel.impl.locking.Locks;
+import org.neo4j.kernel.impl.locking.LocksFactory;
+import org.neo4j.storageengine.api.lock.ResourceType;
+
+public class CommunityLocksFactory implements LocksFactory
+{
+    @Override
+    public Locks newInstance( Config config, Clock clock, ResourceType[] resourceTypes )
+    {
+        return new CommunityLockManger( config, clock );
+    }
+}

community/kernel/src/test/java/org/neo4j/kernel/impl/locking/community/CommunityLocksFactoryTest.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.kernel.impl.locking.community;
+
+import org.junit.jupiter.api.Test;
+
+import org.neo4j.kernel.configuration.Config;
+import org.neo4j.kernel.impl.locking.Locks;
+import org.neo4j.kernel.impl.locking.ResourceTypes;
+import org.neo4j.time.Clocks;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.instanceOf;
+import static org.junit.jupiter.api.Assertions.assertNotSame;
+
+class CommunityLocksFactoryTest
+{
+
+    @Test
+    void createDifferentCommunityLockManagers()
+    {
+        CommunityLocksFactory factory = new CommunityLocksFactory();
+        Locks locks1 = factory.newInstance( Config.defaults(), Clocks.systemClock(), ResourceTypes.values() );
+        Locks locks2 = factory.newInstance( Config.defaults(), Clocks.systemClock(), ResourceTypes.values() );
+        assertNotSame( locks1, locks2 );
+        assertThat( locks1, instanceOf( CommunityLockManger.class ) );
+        assertThat( locks2, instanceOf( CommunityLockManger.class ) );
+    }
+}

community/neo4j/src/main/java/org/neo4j/graphdb/factory/EditionLocksFactories.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2002-2018 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.neo4j.graphdb.factory;
+
+import java.time.Clock;
+
+import org.neo4j.graphdb.factory.module.CommunityEditionModule;
+import org.neo4j.helpers.Service;
+import org.neo4j.kernel.configuration.Config;
+import org.neo4j.kernel.impl.locking.DynamicLocksFactory;
+import org.neo4j.kernel.impl.locking.Locks;
+import org.neo4j.kernel.impl.locking.LocksFactory;
+import org.neo4j.kernel.impl.locking.ResourceTypes;
+import org.neo4j.kernel.impl.locking.community.CommunityLocksFactory;
+import org.neo4j.kernel.impl.logging.LogService;
+
+public final class EditionLocksFactories
+{
+    public static Locks createLockManager( LocksFactory locksFactory, Config config, Clock clock )
+    {
+        return locksFactory.newInstance( config, clock, ResourceTypes.values() );
+    }
+
+    public static LocksFactory createLockFactory( Config config, LogService logging )
+    {
+        String key = config.get( GraphDatabaseSettings.lock_manager );
+        for ( DynamicLocksFactory candidate : Service.load( DynamicLocksFactory.class ) )
+        {
+            String candidateId = candidate.getKeys().iterator().next();
+            if ( key.equals( candidateId ) )
+            {
+                return candidate;
+            }
+            else if ( "".equals( key ) )
+            {
+                logging.getInternalLog( CommunityEditionModule.class )
+                        .info( "No locking implementation specified, defaulting to '" + candidateId + "'" );
+                return candidate;
+            }
+        }
+
+        if ( "community".equals( key ) )
+        {
+            return new CommunityLocksFactory();
+        }
+        else if ( "".equals( key ) )
+        {
+            logging.getInternalLog( CommunityEditionModule.class )
+                    .info( "No locking implementation specified, defaulting to 'community'" );
+            return new CommunityLocksFactory();
+        }
+
+        throw new IllegalArgumentException( "No lock manager found with the name '" + key + "'." );
+    }
+}

community/neo4j/src/main/java/org/neo4j/graphdb/factory/module/CommunityEditionModule.java

@@ -20,12 +20,10 @@
 package org.neo4j.graphdb.factory.module;
 
 import java.io.File;
-import java.time.Clock;
 import java.util.function.Predicate;
 
 import org.neo4j.function.Predicates;
 import org.neo4j.graphdb.factory.GraphDatabaseSettings;
-import org.neo4j.helpers.Service;
 import org.neo4j.internal.kernel.api.exceptions.KernelException;
 import org.neo4j.io.fs.FileSystemAbstraction;
 import org.neo4j.io.pagecache.IOLimiter;
@@ -52,10 +50,9 @@
 import org.neo4j.kernel.impl.factory.ReadOnly;
 import org.neo4j.kernel.impl.index.IndexConfigStore;
 import org.neo4j.kernel.impl.locking.Locks;
-import org.neo4j.kernel.impl.locking.ResourceTypes;
+import org.neo4j.kernel.impl.locking.LocksFactory;
 import org.neo4j.kernel.impl.locking.SimpleStatementLocksFactory;
 import org.neo4j.kernel.impl.locking.StatementLocksFactory;
-import org.neo4j.kernel.impl.locking.community.CommunityLockManger;
 import org.neo4j.kernel.impl.logging.LogService;
 import org.neo4j.kernel.impl.proc.Procedures;
 import org.neo4j.kernel.impl.store.id.DefaultIdGeneratorFactory;
@@ -70,6 +67,9 @@
 import org.neo4j.kernel.lifecycle.LifeSupport;
 import org.neo4j.udc.UsageData;
 
+import static org.neo4j.graphdb.factory.EditionLocksFactories.createLockFactory;
+import static org.neo4j.graphdb.factory.EditionLocksFactories.createLockManager;
+
 /**
  * This implementation of {@link EditionModule} creates the implementations of services
  * that are specific to the Community edition.
@@ -97,7 +97,8 @@ public CommunityEditionModule( PlatformModule platformModule )
         dependencies.satisfyDependency(
                 SslPolicyLoader.create( config, logging.getInternalLogProvider() ) ); // for bolt and web server
 
-        locksSupplier = () -> createLockManager( config, platformModule.clock, logging );
+        LocksFactory lockFactory = createLockFactory( config, logging );
+        locksSupplier = () -> createLockManager( lockFactory, config, platformModule.clock );
         statementLocksFactoryProvider = locks -> createStatementLocksFactory( locks, config, logging );
 
         idTypeConfigurationProvider = createIdTypeConfigurationProvider( config );
@@ -215,38 +216,6 @@ protected IdGeneratorFactory createIdGeneratorFactory( FileSystemAbstraction fs,
         return new DefaultIdGeneratorFactory( fs, idTypeConfigurationProvider );
     }
 
-    public static Locks createLockManager( Config config, Clock clock, LogService logging )
-    {
-        String key = config.get( GraphDatabaseSettings.lock_manager );
-        for ( Locks.Factory candidate : Service.load( Locks.Factory.class ) )
-        {
-            String candidateId = candidate.getKeys().iterator().next();
-            if ( key.equals( candidateId ) )
-            {
-                return candidate.newInstance( config, clock, ResourceTypes.values() );
-            }
-            else if ( key.equals( "" ) )
-            {
-                logging.getInternalLog( CommunityEditionModule.class )
-                        .info( "No locking implementation specified, defaulting to '" + candidateId + "'" );
-                return candidate.newInstance( config, clock, ResourceTypes.values() );
-            }
-        }
-
-        if ( key.equals( "community" ) )
-        {
-            return new CommunityLockManger( config, clock );
-        }
-        else if ( key.equals( "" ) )
-        {
-            logging.getInternalLog( CommunityEditionModule.class )
-                    .info( "No locking implementation specified, defaulting to 'community'" );
-            return new CommunityLockManger( config, clock );
-        }
-
-        throw new IllegalArgumentException( "No lock manager found with the name '" + key + "'." );
-    }
-
     protected TransactionHeaderInformationFactory createHeaderInformationFactory()
     {
         return TransactionHeaderInformationFactory.DEFAULT;