Added database name in the ResultSummary.

driver/src/main/java/org/neo4j/driver/SessionParametersTemplate.java

@@ -58,8 +58,9 @@ public interface SessionParametersTemplate
 
     /**
      * Set the database that the newly created session is going to connect to.
-     * The given database name cannot be <code>null</code>.
-     * If the database name is not set, then the default database configured on the server configuration will be connected when the session established.
+     * If the database name is not set or the database name is set to <code>null</code>,
+     * then the default database configured in the server configuration will be connected when the session is established.
+     * For servers that do not support multi-databases, this database value should not be set or could only be set to <code>null</code>.
      *
      * @param database the database the session going to connect to.
      * @return this builder.

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

@@ -28,6 +28,8 @@
 import org.neo4j.driver.internal.retry.RetryLogic;
 import org.neo4j.driver.internal.spi.ConnectionProvider;
 
+import static org.neo4j.driver.internal.messaging.request.MultiDatabaseUtil.ABSENT_DB_NAME;
+
 public class SessionFactoryImpl implements SessionFactory
 {
     private final ConnectionProvider connectionProvider;
@@ -47,7 +49,7 @@ public class SessionFactoryImpl implements SessionFactory
     public NetworkSession newInstance( SessionParameters parameters )
     {
         BookmarksHolder bookmarksHolder = new DefaultBookmarksHolder( Bookmarks.from( parameters.bookmarks() ) );
-        return createSession( connectionProvider, retryLogic, parameters.database(), parameters.defaultAccessMode(), bookmarksHolder, logging );
+        return createSession( connectionProvider, retryLogic, parameters.database().orElse( ABSENT_DB_NAME ), parameters.defaultAccessMode(), bookmarksHolder, logging );
     }
 
     @Override

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

@@ -21,6 +21,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 
 import org.neo4j.driver.AccessMode;
 import org.neo4j.driver.SessionParametersTemplate;
@@ -87,11 +88,11 @@ public AccessMode defaultAccessMode()
 
     /**
      * The database where the session is going to connect to.
-     * @return the database name where the session is going to connect to.
+     * @return the nullable database name where the session is going to connect to.
      */
-    public String database()
+    public Optional<String> database()
     {
-        return database;
+        return Optional.ofNullable( database );
     }
 
     @Override
@@ -125,7 +126,7 @@ public static class Template implements SessionParametersTemplate
     {
         private List<String> bookmarks = null;
         private AccessMode defaultAccessMode = AccessMode.WRITE;
-        private String database = ABSENT_DB_NAME;
+        private String database = null;
 
         private Template()
         {
@@ -162,7 +163,11 @@ public Template withDefaultAccessMode( AccessMode mode )
         @Override
         public Template withDatabase( String database )
         {
-            Objects.requireNonNull( database, "Database cannot be null." );
+            if ( ABSENT_DB_NAME.equals( database ) )
+            {
+                // Disallow users to use bolt internal value directly. To users, this is totally an illegal database name.
+                throw new IllegalArgumentException( String.format( "Illegal database name '%s'.", database ) );
+            }
             this.database = database;
             return this;
         }

driver/src/main/java/org/neo4j/driver/internal/summary/InternalDatabaseInfo.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.neo4j.driver.internal.summary;
+
+import java.util.Objects;
+
+import org.neo4j.driver.summary.DatabaseInfo;
+
+public class InternalDatabaseInfo implements DatabaseInfo
+{
+    public static DatabaseInfo DEFAULT_DATABASE_INFO = new InternalDatabaseInfo( null );
+
+    private final String name;
+
+    public InternalDatabaseInfo( String name )
+    {
+        this.name = name;
+    }
+
+    @Override
+    public String name()
+    {
+        return this.name;
+    }
+
+    @Override
+    public boolean equals( Object o )
+    {
+        if ( this == o )
+        {
+            return true;
+        }
+        if ( o == null || getClass() != o.getClass() )
+        {
+            return false;
+        }
+        InternalDatabaseInfo that = (InternalDatabaseInfo) o;
+        return Objects.equals( name, that.name );
+    }
+
+    @Override
+    public int hashCode()
+    {
+        return Objects.hash( name );
+    }
+
+    @Override
+    public String toString()
+    {
+        return "InternalDatabaseInfo{" + "name='" + name + '\'' + '}';
+    }
+}

driver/src/main/java/org/neo4j/driver/internal/summary/InternalResultSummary.java

@@ -24,6 +24,7 @@
 import java.util.concurrent.TimeUnit;
 
 import org.neo4j.driver.Statement;
+import org.neo4j.driver.summary.DatabaseInfo;
 import org.neo4j.driver.summary.Notification;
 import org.neo4j.driver.summary.Plan;
 import org.neo4j.driver.summary.ProfiledPlan;
@@ -43,13 +44,14 @@ public class InternalResultSummary implements ResultSummary
     private final List<Notification> notifications;
     private final long resultAvailableAfter;
     private final long resultConsumedAfter;
+    private final DatabaseInfo databaseInfo;
 
-    public InternalResultSummary( Statement statement, ServerInfo serverInfo, StatementType statementType,
-            SummaryCounters counters, Plan plan, ProfiledPlan profile, List<Notification> notifications,
-            long resultAvailableAfter, long resultConsumedAfter )
+    public InternalResultSummary( Statement statement, ServerInfo serverInfo, DatabaseInfo databaseInfo, StatementType statementType,
+            SummaryCounters counters, Plan plan, ProfiledPlan profile, List<Notification> notifications, long resultAvailableAfter, long resultConsumedAfter )
     {
         this.statement = statement;
         this.serverInfo = serverInfo;
+        this.databaseInfo = databaseInfo;
         this.statementType = statementType;
         this.counters = counters;
         this.plan = resolvePlan( plan, profile );
@@ -127,6 +129,12 @@ public ServerInfo server()
         return serverInfo;
     }
 
+    @Override
+    public DatabaseInfo database()
+    {
+        return databaseInfo;
+    }
+
     @Override
     public boolean equals( Object o )
     {
@@ -163,6 +171,7 @@ public String toString()
         return "InternalResultSummary{" +
                "statement=" + statement +
                ", serverInfo=" + serverInfo +
+               ", databaseInfo=" + databaseInfo +
                ", statementType=" + statementType +
                ", counters=" + counters +
                ", plan=" + plan +

driver/src/main/java/org/neo4j/driver/internal/summary/InternalServerInfo.java

@@ -18,6 +18,8 @@
  */
 package org.neo4j.driver.internal.summary;
 
+import java.util.Objects;
+
 import org.neo4j.driver.internal.BoltServerAddress;
 import org.neo4j.driver.internal.util.ServerVersion;
 import org.neo4j.driver.summary.ServerInfo;
@@ -44,4 +46,31 @@ public String version()
     {
         return version;
     }
+
+    @Override
+    public boolean equals( Object o )
+    {
+        if ( this == o )
+        {
+            return true;
+        }
+        if ( o == null || getClass() != o.getClass() )
+        {
+            return false;
+        }
+        InternalServerInfo that = (InternalServerInfo) o;
+        return Objects.equals( address, that.address ) && Objects.equals( version, that.version );
+    }
+
+    @Override
+    public int hashCode()
+    {
+        return Objects.hash( address, version );
+    }
+
+    @Override
+    public String toString()
+    {
+        return "InternalServerInfo{" + "address='" + address + '\'' + ", version='" + version + '\'' + '}';
+    }
 }

driver/src/main/java/org/neo4j/driver/internal/util/MetadataExtractor.java

@@ -23,17 +23,19 @@
 import java.util.List;
 import java.util.Map;
 
+import org.neo4j.driver.Statement;
+import org.neo4j.driver.Value;
+import org.neo4j.driver.exceptions.UntrustedServerException;
 import org.neo4j.driver.internal.Bookmarks;
 import org.neo4j.driver.internal.spi.Connection;
+import org.neo4j.driver.internal.summary.InternalDatabaseInfo;
 import org.neo4j.driver.internal.summary.InternalNotification;
 import org.neo4j.driver.internal.summary.InternalPlan;
 import org.neo4j.driver.internal.summary.InternalProfiledPlan;
 import org.neo4j.driver.internal.summary.InternalResultSummary;
 import org.neo4j.driver.internal.summary.InternalServerInfo;
 import org.neo4j.driver.internal.summary.InternalSummaryCounters;
-import org.neo4j.driver.Statement;
-import org.neo4j.driver.Value;
-import org.neo4j.driver.exceptions.UntrustedServerException;
+import org.neo4j.driver.summary.DatabaseInfo;
 import org.neo4j.driver.summary.Notification;
 import org.neo4j.driver.summary.Plan;
 import org.neo4j.driver.summary.ProfiledPlan;
@@ -42,6 +44,7 @@
 import org.neo4j.driver.summary.StatementType;
 
 import static java.util.Collections.emptyList;
+import static org.neo4j.driver.internal.summary.InternalDatabaseInfo.DEFAULT_DATABASE_INFO;
 import static org.neo4j.driver.internal.types.InternalTypeSystem.TYPE_SYSTEM;
 
 public class MetadataExtractor
@@ -99,12 +102,26 @@ public long extractResultAvailableAfter( Map<String,Value> metadata )
     public ResultSummary extractSummary( Statement statement, Connection connection, long resultAvailableAfter, Map<String,Value> metadata )
     {
         ServerInfo serverInfo = new InternalServerInfo( connection.serverAddress(), connection.serverVersion() );
-        return new InternalResultSummary( statement, serverInfo, extractStatementType( metadata ),
-                extractCounters( metadata ), extractPlan( metadata ), extractProfiledPlan( metadata ),
-                extractNotifications( metadata ), resultAvailableAfter, extractResultConsumedAfter( metadata, resultConsumedAfterMetadataKey ) );
+        DatabaseInfo dbInfo = extractDatabaseInfo( metadata );
+        return new InternalResultSummary( statement, serverInfo, dbInfo, extractStatementType( metadata ), extractCounters( metadata ), extractPlan( metadata ),
+                extractProfiledPlan( metadata ), extractNotifications( metadata ), resultAvailableAfter,
+                extractResultConsumedAfter( metadata, resultConsumedAfterMetadataKey ) );
+    }
+
+    public static DatabaseInfo extractDatabaseInfo( Map<String,Value> metadata )
+    {
+        Value dbValue = metadata.get( "db" );
+        if ( dbValue == null || dbValue.isNull() )
+        {
+            return DEFAULT_DATABASE_INFO;
+        }
+        else
+        {
+            return new InternalDatabaseInfo( dbValue.asString() );
+        }
     }
 
-    public Bookmarks extractBookmarks( Map<String,Value> metadata )
+    public static Bookmarks extractBookmarks( Map<String,Value> metadata )
     {
         Value bookmarkValue = metadata.get( "bookmark" );
         if ( bookmarkValue != null && !bookmarkValue.isNull() && bookmarkValue.hasType( TYPE_SYSTEM.STRING() ) )

driver/src/main/java/org/neo4j/driver/summary/DatabaseInfo.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (c) 2002-2019 "Neo4j,"
+ * Neo4j Sweden AB [http://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.neo4j.driver.summary;
+
+/**
+ * Provides basic information about where a {@link ResultSummary} is obtained from.
+ */
+public interface DatabaseInfo
+{
+    /**
+     * The name of the database where a {@link ResultSummary} is obtained from.
+     * Default to {@code null} if servers does not support multi-databases.
+     * @return the name of the database where a {@link ResultSummary} is obtained from
+     */
+    String name();
+}

driver/src/main/java/org/neo4j/driver/summary/ResultSummary.java

@@ -110,7 +110,13 @@ public interface ResultSummary
 
     /**
      * The basic information of the server where the result is obtained from
-     * @return basic information of the server where the result is obtain from
+     * @return basic information of the server where the result is obtained from
      */
     ServerInfo server();
+
+    /**
+     * The basic information of the database where the result is obtained from
+     * @return the basic information of the database where the result is obtained from
+     */
+    DatabaseInfo database();
 }

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

@@ -34,7 +34,9 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.neo4j.driver.internal.SessionParameters.empty;
 import static org.neo4j.driver.internal.SessionParameters.template;
 import static org.neo4j.driver.internal.messaging.request.MultiDatabaseUtil.ABSENT_DB_NAME;
@@ -47,7 +49,7 @@ void shouldReturnDefaultValues() throws Throwable
         SessionParameters parameters = empty();
 
         Assert.assertEquals( AccessMode.WRITE, parameters.defaultAccessMode() );
-        assertEquals( ABSENT_DB_NAME, parameters.database() );
+        assertFalse( parameters.database().isPresent() );
         assertNull( parameters.bookmarks() );
     }
 
@@ -60,18 +62,28 @@ void shouldChangeAccessMode( AccessMode mode ) throws Throwable
     }
 
     @ParameterizedTest
-    @ValueSource( strings = {"", "foo", "data", ABSENT_DB_NAME} )
+    @ValueSource( strings = {"foo", "data", "my awesome database", " "} )
     void shouldChangeDatabaseName( String databaseName )
     {
         SessionParameters parameters = template().withDatabase( databaseName ).build();
-        assertEquals( databaseName, parameters.database() );
+        assertTrue( parameters.database().isPresent() );
+        assertEquals( databaseName, parameters.database().get() );
     }
 
     @Test
-    void shouldForbiddenNullDatabaseName() throws Throwable
+    void shouldAllowNullDatabaseName() throws Throwable
     {
-        NullPointerException error = assertThrows( NullPointerException.class, () -> template().withDatabase( null ).build());
-        assertThat( error.getMessage(), equalTo( "Database cannot be null." ) );
+        SessionParameters parameters = template().withDatabase( null ).build();
+        assertFalse( parameters.database().isPresent() );
+        assertEquals( "", parameters.database().orElse( ABSENT_DB_NAME ) );
+    }
+
+    @ParameterizedTest
+    @ValueSource( strings = {"", ABSENT_DB_NAME} )
+    void shouldForbiddenEmptyStringDatabaseName( String databaseName ) throws Throwable
+    {
+        IllegalArgumentException error = assertThrows( IllegalArgumentException.class, () -> template().withDatabase( databaseName ).build());
+        assertThat( error.getMessage(), equalTo( "Illegal database name ''." ) );
     }
 
     @Test