for #1941, add DatabaseFrontendEngine.getCommandPacketTypeLoader

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/mysql/MySQLFrontendEngine.java

@@ -108,6 +108,11 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
         }
     }
     
+    @Override
+    public MySQLCommandPacketTypeLoader getCommandPacketTypeLoader(final PacketPayload payload) {
+        return new MySQLCommandPacketTypeLoader((MySQLPacketPayload) payload);
+    }
+    
     @Override
     public void executeCommand(final ChannelHandlerContext context, final PacketPayload packetPayload, final BackendConnection backendConnection) {
         try {
@@ -126,7 +131,7 @@ public final class MySQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     private void writePackets(final ChannelHandlerContext context, final MySQLPacketPayload payload, final BackendConnection backendConnection) throws SQLException {
-        MySQLCommandPacketType commandPacketType = new MySQLCommandPacketTypeLoader(payload).getCommandPacketType();
+        MySQLCommandPacketType commandPacketType = getCommandPacketTypeLoader(payload).getCommandPacketType();
         MySQLCommandPacket commandPacket = MySQLCommandPacketFactory.newInstance(commandPacketType, payload);
         CommandExecutor<MySQLPacket> commandPacketExecutor = MySQLCommandExecutorFactory.newInstance(commandPacketType, commandPacket, backendConnection);
         Collection<MySQLPacket> responsePackets = commandPacketExecutor.execute();

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/postgresql/PostgreSQLFrontendEngine.java

@@ -116,6 +116,11 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
         }
     }
     
+    @Override
+    public PostgreSQLCommandPacketTypeLoader getCommandPacketTypeLoader(final PacketPayload payload) {
+        return new PostgreSQLCommandPacketTypeLoader((PostgreSQLPacketPayload) payload);
+    }
+    
     @Override
     public void executeCommand(final ChannelHandlerContext context, final PacketPayload packetPayload, final BackendConnection backendConnection) {
         try {
@@ -131,7 +136,7 @@ public final class PostgreSQLFrontendEngine implements DatabaseFrontendEngine {
     }
     
     private void writePackets(final ChannelHandlerContext context, final PostgreSQLPacketPayload payload, final BackendConnection backendConnection) throws SQLException {
-        PostgreSQLCommandPacketType commandPacketType = new PostgreSQLCommandPacketTypeLoader(payload).getCommandPacketType();
+        PostgreSQLCommandPacketType commandPacketType = getCommandPacketTypeLoader(payload).getCommandPacketType();
         PostgreSQLCommandPacket commandPacket = PostgreSQLCommandPacketFactory.newInstance(commandPacketType, payload, backendConnection.getConnectionId());
         CommandExecutor<PostgreSQLPacket> commandPacketExecutor = PostgreSQLCommandExecutorFactory.newInstance(commandPacketType, commandPacket, backendConnection);
         Collection<PostgreSQLPacket> responsePackets = commandPacketExecutor.execute();

sharding-proxy/sharding-proxy-frontend/sharding-proxy-frontend-spi/src/main/java/org/apache/shardingsphere/shardingproxy/frontend/spi/DatabaseFrontendEngine.java

@@ -20,6 +20,7 @@ package org.apache.shardingsphere.shardingproxy.frontend.spi;
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandlerContext;
 import org.apache.shardingsphere.shardingproxy.backend.communication.jdbc.connection.BackendConnection;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketTypeLoader;
 import org.apache.shardingsphere.shardingproxy.transport.api.payload.PacketPayload;
 
 /**
@@ -69,6 +70,14 @@ public interface DatabaseFrontendEngine {
      */
     boolean auth(ChannelHandlerContext context, ByteBuf message, BackendConnection backendConnection);
     
+    /**
+     * Get command packet type loader.
+     * 
+     * @param packetPayload packet payload
+     * @return command packet type loader
+     */
+    CommandPacketTypeLoader getCommandPacketTypeLoader(PacketPayload packetPayload);
+    
     /**
      * Execute command.
      * 

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/transport/mysql/packet/command/MySQLCommandPacketType.java

@@ -19,7 +19,7 @@ package org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command;
 
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
-import org.apache.shardingsphere.shardingproxy.transport.common.packet.CommandPacketType;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketType;
 
 /**
  * MySQL command packet type.

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-mysql/src/main/java/org/apache/shardingsphere/shardingproxy/transport/mysql/packet/command/MySQLCommandPacketTypeLoader.java

@@ -19,7 +19,7 @@ package org.apache.shardingsphere.shardingproxy.transport.mysql.packet.command;
 
 import com.google.common.base.Preconditions;
 import lombok.RequiredArgsConstructor;
-import org.apache.shardingsphere.shardingproxy.transport.common.packet.CommandPacketTypeLoader;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketTypeLoader;
 import org.apache.shardingsphere.shardingproxy.transport.mysql.payload.MySQLPacketPayload;
 
 /**

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/transport/postgresql/packet/command/PostgreSQLCommandPacketType.java

@@ -19,7 +19,7 @@ package org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.comm
 
 import lombok.Getter;
 import lombok.RequiredArgsConstructor;
-import org.apache.shardingsphere.shardingproxy.transport.common.packet.CommandPacketType;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketType;
 
 /**
  * PostgreSQL command packet type.

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-postgresql/src/main/java/org/apache/shardingsphere/shardingproxy/transport/postgresql/packet/command/PostgreSQLCommandPacketTypeLoader.java

@@ -18,7 +18,7 @@
 package org.apache.shardingsphere.shardingproxy.transport.postgresql.packet.command;
 
 import lombok.RequiredArgsConstructor;
-import org.apache.shardingsphere.shardingproxy.transport.common.packet.CommandPacketTypeLoader;
+import org.apache.shardingsphere.shardingproxy.transport.api.packet.CommandPacketTypeLoader;
 import org.apache.shardingsphere.shardingproxy.transport.postgresql.payload.PostgreSQLPacketPayload;
 
 /**

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-core/src/main/java/org/apache/shardingsphere/shardingproxy/transport/common/packet/CommandPacketType.java → sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-spi/src/main/java/org/apache/shardingsphere/shardingproxy/transport/api/packet/CommandPacketType.java

@@ -15,7 +15,7 @@
  * limitations under the License.
  */
 
-package org.apache.shardingsphere.shardingproxy.transport.common.packet;
+package org.apache.shardingsphere.shardingproxy.transport.api.packet;
 
 /**
  * Command packet type.

sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-core/src/main/java/org/apache/shardingsphere/shardingproxy/transport/common/packet/CommandPacketTypeLoader.java → sharding-proxy/sharding-proxy-transport/sharding-proxy-transport-spi/src/main/java/org/apache/shardingsphere/shardingproxy/transport/api/packet/CommandPacketTypeLoader.java

@@ -15,14 +15,14 @@
  * limitations under the License.
  */
 
-package org.apache.shardingsphere.shardingproxy.transport.common.packet;
+package org.apache.shardingsphere.shardingproxy.transport.api.packet;
 
 /**
  * Command packet type loader.
  * 
- * @param <T> Type of command packet type
- * 
  * @author zhangliang
+ * 
+ * @param <T> Type of command packet type
  */
 public interface CommandPacketTypeLoader<T extends CommandPacketType> {