Extract constants with minimum and maximum TCP protocol versions

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

@@ -105,6 +105,16 @@ public class Constants {
      */
     public static final int TCP_PROTOCOL_VERSION_17 = 17;
 
+    /**
+     * Minimum supported version of TCP protocol.
+     */
+    public static final int TCP_PROTOCOL_VERSION_MIN_SUPPORTED = TCP_PROTOCOL_VERSION_6;
+
+    /**
+     * Maximum supported version of TCP protocol.
+     */
+    public static final int TCP_PROTOCOL_VERSION_MAX_SUPPORTED = TCP_PROTOCOL_VERSION_17;
+
     /**
      * The major version of this database.
      */

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

@@ -117,8 +117,8 @@ public class SessionRemote extends SessionWithState implements DataHandler {
         Transfer trans = new Transfer(this, socket);
         trans.setSSL(ci.isSSL());
         trans.init();
-        trans.writeInt(Constants.TCP_PROTOCOL_VERSION_6);
-        trans.writeInt(Constants.TCP_PROTOCOL_VERSION_17);
+        trans.writeInt(Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
+        trans.writeInt(Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED);
         trans.writeString(db);
         trans.writeString(ci.getOriginalURL());
         trans.writeString(ci.getUserName());

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

@@ -89,15 +89,15 @@ public class TcpServerThread implements Runnable {
                 }
                 int minClientVersion = transfer.readInt();
                 int maxClientVersion = transfer.readInt();
-                if (maxClientVersion < Constants.TCP_PROTOCOL_VERSION_6) {
+                if (maxClientVersion < Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED) {
                     throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
-                            "" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_6);
-                } else if (minClientVersion > Constants.TCP_PROTOCOL_VERSION_17) {
+                            "" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
+                } else if (minClientVersion > Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED) {
                     throw DbException.get(ErrorCode.DRIVER_VERSION_ERROR_2,
-                            "" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_17);
+                            "" + clientVersion, "" + Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED);
                 }
-                if (maxClientVersion >= Constants.TCP_PROTOCOL_VERSION_17) {
-                    clientVersion = Constants.TCP_PROTOCOL_VERSION_17;
+                if (maxClientVersion >= Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED) {
+                    clientVersion = Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED;
                 } else {
                     clientVersion = maxClientVersion;
                 }

h2/src/main/org/h2/store/FileLock.java

@@ -210,8 +210,8 @@ public class FileLock implements Runnable {
                     Constants.DEFAULT_TCP_PORT, false);
             Transfer transfer = new Transfer(null, socket);
             transfer.init();
-            transfer.writeInt(Constants.TCP_PROTOCOL_VERSION_6);
-            transfer.writeInt(Constants.TCP_PROTOCOL_VERSION_17);
+            transfer.writeInt(Constants.TCP_PROTOCOL_VERSION_MIN_SUPPORTED);
+            transfer.writeInt(Constants.TCP_PROTOCOL_VERSION_MAX_SUPPORTED);
             transfer.writeString(null);
             transfer.writeString(null);
             transfer.writeString(id);