Simplify SessionFactory a bit.

h2/src/main/org/h2/engine/Engine.java

@@ -24,15 +24,12 @@ import org.h2.util.StringUtils;
  * It is also responsible for opening and creating new databases.
  * This is a singleton class.
  */
-public class Engine {
+public class Engine implements SessionFactory {
 
     private static final Engine INSTANCE = new Engine();
-    private static final HashMap<String, Database> DATABASES = New.hashMap();
-    private volatile long wrongPasswordDelay = SysProperties.DELAY_WRONG_PASSWORD_MIN;
 
-    private Engine() {
-        // don't allow others to instantiate
-    }
+    private final HashMap<String, Database> databases = New.hashMap();
+    private volatile long wrongPasswordDelay = SysProperties.DELAY_WRONG_PASSWORD_MIN;
 
     public static Engine getInstance() {
         return INSTANCE;
@@ -45,7 +42,7 @@ public class Engine {
         if (openNew || ci.isUnnamedInMemory()) {
             database = null;
         } else {
-            database = DATABASES.get(name);
+            database = databases.get(name);
         }
         User user = null;
         boolean opened = false;
@@ -64,7 +61,7 @@ public class Engine {
                 database.setMasterUser(user);
             }
             if (!ci.isUnnamedInMemory()) {
-                DATABASES.put(name, database);
+                databases.put(name, database);
             }
         }
         synchronized (database) {
@@ -108,7 +105,11 @@ public class Engine {
      * @param ci the connection information
      * @return the session
      */
-    public Session getSession(ConnectionInfo ci) {
+    public Session createSession(ConnectionInfo ci) {
+        return INSTANCE.createSessionAndValidate(ci);
+    }
+
+    private Session createSessionAndValidate(ConnectionInfo ci) {
         try {
             ConnectionInfo backup = null;
             String lockMethodName = ci.getProperty("FILE_LOCK", null);
@@ -213,7 +214,7 @@ public class Engine {
      * @param name the database name
      */
     public void close(String name) {
-        DATABASES.remove(name);
+        databases.remove(name);
     }
 
     /**

h2/src/main/org/h2/engine/Session.java

@@ -42,7 +42,7 @@ import org.h2.value.ValueString;
  * mode, this object resides on the server side and communicates with a
  * SessionRemote object on the client side.
  */
-public class Session extends SessionWithState implements SessionFactory {
+public class Session extends SessionWithState {
 
     /**
      * This special log position means that the log entry has been written.
@@ -118,10 +118,6 @@ public class Session extends SessionWithState implements SessionFactory {
         this.currentSchemaName = Constants.SCHEMA_MAIN;
     }
 
-    public SessionInterface createSession(ConnectionInfo ci) {
-        return Engine.getInstance().getSession(ci);
-    }
-
     public boolean setCommitOrRollbackDisabled(boolean x) {
         boolean old = commitOrRollbackDisabled;
         commitOrRollbackDisabled = x;
@@ -1178,7 +1174,7 @@ public class Session extends SessionWithState implements SessionFactory {
     public SessionInterface reconnect(boolean write) {
         readSessionState();
         close();
-        Session newSession = Engine.getInstance().getSession(connectionInfo);
+        Session newSession = Engine.getInstance().createSession(connectionInfo);
         newSession.sessionState = sessionState;
         newSession.recreateSessionState();
         if (write) {

h2/src/main/org/h2/jdbc/JdbcConnection.java

@@ -108,7 +108,7 @@ public class JdbcConnection extends TraceObject implements Connection {
             }
             checkJavaVersion();
             // this will return an embedded or server connection
-            session = new SessionRemote().createSession(ci);
+            session = new SessionRemote(ci).createSession(ci);
             trace = session.getTrace();
             int id = getNextId(TraceObject.CONNECTION);
             setTrace(trace, TraceObject.CONNECTION, id);

h2/src/main/org/h2/server/TcpServerThread.java

@@ -121,8 +121,7 @@ public class TcpServerThread implements Runnable {
                 for (int i = 0; i < len; i++) {
                     ci.setProperty(transfer.readString(), transfer.readString());
                 }
-                Engine engine = Engine.getInstance();
-                session = engine.getSession(ci);
+                session = Engine.getInstance().createSession(ci);
                 transfer.setSession(session);
                 transfer.writeInt(SessionRemote.STATUS_OK);
                 transfer.writeInt(clientVersion);