refactor

src/main/java/com/alibaba/druid/mapping/MappingEngine.java

@@ -46,12 +46,12 @@ public class MappingEngine {
         return provider.createOutputVisitor(this, out);
     }
 
-    public SQLSelectQueryBlock explainToSQLObject(String sql) {
-        return provider.explainToSQLObject(this, sql);
+    public SQLSelectQueryBlock explainToSelectSQLObject(String sql) {
+        return provider.explainToSelectSQLObject(this, sql);
     }
 
-    public String explainToSQL(String sql) {
-        SQLSelectQueryBlock query = explainToSQLObject(sql);
+    public String explainToSelectSQL(String sql) {
+        SQLSelectQueryBlock query = explainToSelectSQLObject(sql);
 
         query.accept(this.createMappingVisitor());
 

src/main/java/com/alibaba/druid/mapping/spi/MSSQLServerMappingProvider.java

@@ -21,7 +21,7 @@ public class MSSQLServerMappingProvider implements MappingProvider {
         return new SQLServerOutputVisitor(out);
     }
 
-    public SQLSelectQueryBlock explainToSQLObject(MappingEngine engine, String sql) {
+    public SQLSelectQueryBlock explainToSelectSQLObject(MappingEngine engine, String sql) {
         SQLServerSelectParser selectParser = new SQLServerSelectParser(sql);
         SQLServerSelectQueryBlock query = (SQLServerSelectQueryBlock) selectParser.query();
 

src/main/java/com/alibaba/druid/mapping/spi/MappingProvider.java

@@ -10,5 +10,5 @@ public interface MappingProvider {
 
     SQLASTOutputVisitor createOutputVisitor(MappingEngine engine, Appendable out);
 
-    SQLSelectQueryBlock explainToSQLObject(MappingEngine engine, String sql);
+    SQLSelectQueryBlock explainToSelectSQLObject(MappingEngine engine, String sql);
 }

src/main/java/com/alibaba/druid/mapping/spi/MySqlMappingProvider.java

@@ -21,7 +21,7 @@ public class MySqlMappingProvider implements MappingProvider {
         return new MySqlOutputVisitor(out);
     }
 
-    public SQLSelectQueryBlock explainToSQLObject(MappingEngine engine, String sql) {
+    public SQLSelectQueryBlock explainToSelectSQLObject(MappingEngine engine, String sql) {
         MySqlSelectParser selectParser = new MySqlSelectParser(sql);
         MySqlSelectQueryBlock query = (MySqlSelectQueryBlock) selectParser.query();
 

src/main/java/com/alibaba/druid/mapping/spi/OracleMappingProvider.java

@@ -19,7 +19,7 @@ public class OracleMappingProvider implements MappingProvider {
         return new OracleOutputVisitor(out);
     }
 
-    public SQLSelectQueryBlock explainToSQLObject(MappingEngine engine, String sql) {
+    public SQLSelectQueryBlock explainToSelectSQLObject(MappingEngine engine, String sql) {
         OracleSelectParser selectParser = new OracleSelectParser(sql);
         OracleSelectQueryBlock query = (OracleSelectQueryBlock) selectParser.query();