added SqlPlatform class with getters to platform specific implementations

core/src/main/java/jef/model/DbContext.java

@@ -1,9 +1,9 @@
 package jef.model;
 
-import jef.Database;
 import jef.DbSet;
 import jef.model.annotations.Clazz;
 import jef.model.constraints.ForeignKeyConstraint;
+import jef.platform.base.Database;
 import jef.serializable.SerializableObject;
 import lombok.Getter;
 

core/src/main/java/jef/model/DbContextOptions.java

@@ -1,6 +1,6 @@
 package jef.model;
 
-import jef.DatabaseOptions;
+import jef.platform.base.DatabaseOptions;
 import lombok.AllArgsConstructor;
 import lombok.Builder;
 import lombok.Getter;

core/src/main/java/jef/platform/SqlPlatform.java

@@ -0,0 +1,14 @@
+package jef.platform;
+
+import jef.platform.base.SqlTypeMapper;
+import jef.platform.base.DatabaseOptions;
+import jef.platform.base.migration.MigrationApplier;
+import jef.platform.base.MigrationOperationTranslator;
+
+import java.sql.Connection;
+
+public interface SqlPlatform {
+    MigrationOperationTranslator getTranslator();
+    SqlTypeMapper getTypeMapper();
+    MigrationApplier getMigrationApplier(Connection connection, DatabaseOptions options);
+}

core/src/main/java/jef/platform/base/Database.java

@@ -1,5 +1,6 @@
-package jef;
+package jef.platform.base;
 
+import jef.MigrationException;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 

core/src/main/java/jef/platform/base/DatabaseOptions.java

@@ -1,4 +1,4 @@
-package jef;
+package jef.platform.base;
 
 import lombok.Getter;
 

core/src/main/java/jef/platform/base/MigrationOperationTranslator.java

@@ -0,0 +1,11 @@
+package jef.platform.base;
+
+import jef.model.migration.operation.MigrationOperation;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.SQLException;
+
+public interface MigrationOperationTranslator {
+    PreparedStatement translate(Connection connection, MigrationOperation op) throws SQLException;
+}

core/src/main/java/jef/platform/base/SqlTypeMapper.java

@@ -1,4 +1,4 @@
-package jef.model;
+package jef.platform.base;
 
 import java.util.Optional;
 

core/src/main/java/jef/platform/base/migration/MigrationApplier.java

@@ -1,10 +1,11 @@
-package jef.mysql.migration;
+package jef.platform.base.migration;
 
-import jef.DatabaseOptions;
 import jef.MigrationException;
 import jef.model.migration.Migration;
 import jef.model.migration.MigrationBuilder;
 import jef.model.migration.operation.MigrationOperation;
+import jef.platform.SqlPlatform;
+import jef.platform.base.DatabaseOptions;
 import lombok.AllArgsConstructor;
 import lombok.Getter;
 
@@ -21,6 +22,7 @@ import java.util.stream.Collectors;
 public abstract class MigrationApplier {
     protected final Connection connection;
     protected final DatabaseOptions options;
+    protected final SqlPlatform sqlPlatform;
 
     public void migrate() throws MigrationException {
         var migrations = findMigrations(options.getMigrationsPackage()); //TODO find all migrations, support multiple db contexts
@@ -47,7 +49,7 @@ public abstract class MigrationApplier {
             connection.setAutoCommit(false);
             try {
                 for (MigrationOperation op : operations) {
-                    var stmt = MysqlMigrationOperationTranslator.translate(connection, op);
+                    var stmt = sqlPlatform.getTranslator().translate(connection, op);
                     try {
                         stmt.execute();
                     } catch (SQLException e) {

core/src/main/java/jef/platform/nul/NullDatabase.java

@@ -0,0 +1,14 @@
+package jef.platform.nul;
+
+import jef.MigrationException;
+import jef.platform.base.Database;
+
+public class NullDatabase extends Database {
+    public NullDatabase() {
+        super(null, null);
+    }
+
+    @Override
+    public void migrate() throws MigrationException {
+    }
+}

core/src/main/java/jef/platform/nul/NullPlatform.java

@@ -0,0 +1,26 @@
+package jef.platform.nul;
+
+import jef.platform.SqlPlatform;
+import jef.platform.base.DatabaseOptions;
+import jef.platform.base.MigrationOperationTranslator;
+import jef.platform.base.SqlTypeMapper;
+import jef.platform.base.migration.MigrationApplier;
+
+import java.sql.Connection;
+
+public class NullPlatform implements SqlPlatform {
+    @Override
+    public MigrationOperationTranslator getTranslator() {
+        return null;
+    }
+
+    @Override
+    public SqlTypeMapper getTypeMapper() {
+        return new NullTypeMapper();
+    }
+
+    @Override
+    public MigrationApplier getMigrationApplier(Connection connection, DatabaseOptions options) {
+        return null;
+    }
+}

core/src/main/java/jef/platform/nul/NullTypeMapper.java

@@ -0,0 +1,12 @@
+package jef.platform.nul;
+
+import jef.platform.base.SqlTypeMapper;
+
+import java.util.Optional;
+
+public class NullTypeMapper extends SqlTypeMapper {
+    @Override
+    public Optional<String> map(String typeName) {
+        return Optional.ofNullable(typeName);
+    }
+}