Move leaked session switch to config

It was previously in system property. This commit makes it part of `Config` so
we have a single place with all configuration parameters.

Author: lutovich

driver/src/main/java/org/neo4j/driver/internal/DriverFactory.java

@@ -129,7 +129,7 @@ ConnectionPool createConnectionPool( AuthToken authToken, SecurityPlan securityP
 
     private static SessionFactory createSessionFactory( Config config )
     {
-        if ( LeakLoggingNetworkSessionFactory.leakLoggingEnabled() )
+        if ( config.logLeakedSessions() )
         {
             return new LeakLoggingNetworkSessionFactory( config.logging() );
         }

driver/src/main/java/org/neo4j/driver/internal/LeakLoggingNetworkSessionFactory.java

@@ -23,24 +23,17 @@
 import org.neo4j.driver.v1.Logging;
 import org.neo4j.driver.v1.Session;
 
-public class LeakLoggingNetworkSessionFactory implements SessionFactory
+class LeakLoggingNetworkSessionFactory implements SessionFactory
 {
-    private static final String SYSTEM_PROPERTY_NAME = "org.neo4j.driver.logSessionLeaks";
     private static final String LOGGER_NAME = "sessionLeak";
 
     private final Logger logger;
 
-    public LeakLoggingNetworkSessionFactory( Logging logging )
+    LeakLoggingNetworkSessionFactory( Logging logging )
     {
         this.logger = logging.getLog( LOGGER_NAME );
     }
 
-    public static boolean leakLoggingEnabled()
-    {
-        String value = System.getProperty( SYSTEM_PROPERTY_NAME );
-        return Boolean.parseBoolean( value );
-    }
-
     @Override
     public Session newInstance( Connection connection )
     {

driver/src/main/java/org/neo4j/driver/internal/NetworkSessionFactory.java

@@ -21,7 +21,7 @@
 import org.neo4j.driver.internal.spi.Connection;
 import org.neo4j.driver.v1.Session;
 
-public class NetworkSessionFactory implements SessionFactory
+class NetworkSessionFactory implements SessionFactory
 {
     @Override
     public Session newInstance( Connection connection )

driver/src/main/java/org/neo4j/driver/internal/SessionFactory.java

@@ -21,7 +21,7 @@
 import org.neo4j.driver.internal.spi.Connection;
 import org.neo4j.driver.v1.Session;
 
-public interface SessionFactory
+interface SessionFactory
 {
     Session newInstance( Connection connection );
 }

driver/src/main/java/org/neo4j/driver/v1/Config.java

@@ -26,6 +26,7 @@
 import org.neo4j.driver.internal.logging.JULogging;
 import org.neo4j.driver.internal.net.pooling.PoolSettings;
 import org.neo4j.driver.v1.util.Immutable;
+import org.neo4j.driver.v1.util.Resource;
 
 import static org.neo4j.driver.v1.Config.TrustStrategy.trustAllCertificates;
 
@@ -48,6 +49,7 @@ public class Config
 {
     /** User defined logging */
     private final Logging logging;
+    private final boolean logLeakedSessions;
 
     private final int maxIdleConnectionPoolSize;
 
@@ -63,6 +65,7 @@ public class Config
     private Config( ConfigBuilder builder)
     {
         this.logging = builder.logging;
+        this.logLeakedSessions = builder.logLeakedSessions;
 
         this.maxIdleConnectionPoolSize = builder.maxIdleConnectionPoolSize;
 
@@ -81,6 +84,16 @@ public Logging logging()
         return logging;
     }
 
+    /**
+     * Check if leaked sessions logging is enabled.
+     *
+     * @return {@code true} if enabled, {@code false} otherwise.
+     */
+    public boolean logLeakedSessions()
+    {
+        return logLeakedSessions;
+    }
+
     /**
      * Max number of connections per URL for this driver.
      * @return the max number of connections
@@ -158,6 +171,7 @@ RoutingSettings routingSettings()
     public static class ConfigBuilder
     {
         private Logging logging = new JULogging( Level.INFO );
+        private boolean logLeakedSessions;
         private int maxIdleConnectionPoolSize = PoolSettings.DEFAULT_MAX_IDLE_CONNECTION_POOL_SIZE;
         private EncryptionLevel encryptionLevel = EncryptionLevel.REQUIRED;
         private TrustStrategy trustStrategy = trustAllCertificates();
@@ -178,6 +192,27 @@ public ConfigBuilder withLogging( Logging logging )
             return this;
         }
 
+        /**
+         * Enable logging of leaked sessions.
+         * <p>
+         * Each {@link Session session} is associated with a network connection and thus is a
+         * {@link Resource resource} that needs to be explicitly closed. Unclosed sessions will result in socket
+         * leaks and could cause {@link OutOfMemoryError}s.
+         * <p>
+         * Session is considered to be leaked when it is finalized via {@link Object#finalize()} while not being
+         * closed. This option turns on logging of such sessions and stacktraces of where they were created.
+         * <p>
+         * <b>Note:</b> this option should mostly be used in testing environments for session leak investigations.
+         * Enabling it will add object finalization overhead.
+         *
+         * @return this builder
+         */
+        public ConfigBuilder withLeakedSessionsLogging()
+        {
+            this.logLeakedSessions = true;
+            return this;
+        }
+
         /**
          * The max number of sessions to keep open at once. Configure this
          * higher if you want more concurrent sessions, or lower if you want

driver/src/test/java/org/neo4j/driver/internal/ConfigTest.java

@@ -27,6 +27,8 @@
 
 import static java.lang.System.getProperty;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 public class ConfigTest
 {
@@ -86,6 +88,16 @@ public void shouldIgnoreLivenessCheckTimeoutSetting() throws Throwable
         assertEquals( -1, config.idleTimeBeforeConnectionTest() );
     }
 
+    @Test
+    public void shouldTurnOnLeakedSessionsLogging()
+    {
+        // leaked sessions logging is turned off by default
+        assertFalse( Config.build().toConfig().logLeakedSessions() );
+
+        // it can be turned on using config
+        assertTrue( Config.build().withLeakedSessionsLogging().toConfig().logLeakedSessions() );
+    }
+
     public static void deleteDefaultKnownCertFileIfExists()
     {
         if( DEFAULT_KNOWN_HOSTS.exists() )

driver/src/test/java/org/neo4j/driver/internal/DriverFactoryTest.java

@@ -100,6 +100,28 @@ public void connectionPoolCloseExceptionIsSupressedWhenDriverCreationFails() thr
         verify( connectionPool ).close();
     }
 
+    @Test
+    public void usesStandardSessionFactoryWhenNothingConfigured()
+    {
+        Config config = Config.defaultConfig();
+        SessionFactoryCapturingDriverFactory factory = new SessionFactoryCapturingDriverFactory();
+
+        factory.newInstance( uri, dummyAuthToken(), dummyRoutingSettings(), config );
+
+        assertThat( factory.capturedSessionFactory, instanceOf( NetworkSessionFactory.class ) );
+    }
+
+    @Test
+    public void usesLeakLoggingSessionFactoryWhenConfigured()
+    {
+        Config config = Config.build().withLeakedSessionsLogging().toConfig();
+        SessionFactoryCapturingDriverFactory factory = new SessionFactoryCapturingDriverFactory();
+
+        factory.newInstance( uri, dummyAuthToken(), dummyRoutingSettings(), config );
+
+        assertThat( factory.capturedSessionFactory, instanceOf( LeakLoggingNetworkSessionFactory.class ) );
+    }
+
     private static AuthToken dummyAuthToken()
     {
         return AuthTokens.basic( "neo4j", "neo4j" );
@@ -139,4 +161,25 @@ ConnectionPool createConnectionPool( AuthToken authToken, SecurityPlan securityP
             return connectionPool;
         }
     }
+
+    private static class SessionFactoryCapturingDriverFactory extends DriverFactory
+    {
+        SessionFactory capturedSessionFactory;
+
+        @Override
+        DirectDriver createDirectDriver( BoltServerAddress address, ConnectionPool connectionPool, Config config,
+                SecurityPlan securityPlan, SessionFactory sessionFactory )
+        {
+            capturedSessionFactory = sessionFactory;
+            return null;
+        }
+
+        @Override
+        RoutingDriver createRoutingDriver( BoltServerAddress address, ConnectionPool connectionPool, Config config,
+                RoutingSettings routingSettings, SecurityPlan securityPlan, SessionFactory sessionFactory )
+        {
+            capturedSessionFactory = sessionFactory;
+            return null;
+        }
+    }
 }