Minor changes for java doc and variable names (#7688)

* Update javadoc

* Update ShardingSphereServiceLoader

* Refactor SQLRouteEngine

* Update java doc

shardingsphere-features/shardingsphere-sharding/shardingsphere-sharding-route/src/main/java/org/apache/shardingsphere/sharding/route/engine/ShardingSQLRouter.java

@@ -59,8 +59,8 @@ public final class ShardingSQLRouter implements SQLRouter<ShardingRule> {
     public RouteContext createRouteContext(final LogicSQL logicSQL, final ShardingRule rule, final ConfigurationProperties props) {
         RouteContext result = new RouteContext();
         SQLStatement sqlStatement = logicSQL.getSqlStatementContext().getSqlStatement();
-        Optional<ShardingStatementValidator> shardingStatementValidator = ShardingStatementValidatorFactory.newInstance(sqlStatement);
-        shardingStatementValidator.ifPresent(validator -> validator.preValidate(rule, logicSQL.getSqlStatementContext(), logicSQL.getParameters(), logicSQL.getSchema().getMetaData()));
+        Optional<ShardingStatementValidator> validator = ShardingStatementValidatorFactory.newInstance(sqlStatement);
+        validator.ifPresent(v -> v.preValidate(rule, logicSQL.getSqlStatementContext(), logicSQL.getParameters(), logicSQL.getSchema().getMetaData()));
         ShardingConditions shardingConditions = getShardingConditions(
                 logicSQL.getParameters(), logicSQL.getSqlStatementContext(), logicSQL.getSchema().getMetaData().getRuleSchemaMetaData().getConfiguredSchemaMetaData(), rule);
         boolean needMergeShardingValues = isNeedMergeShardingValues(logicSQL.getSqlStatementContext(), rule);
@@ -69,7 +69,7 @@ public final class ShardingSQLRouter implements SQLRouter<ShardingRule> {
             mergeShardingConditions(shardingConditions);
         }
         ShardingRouteEngineFactory.newInstance(rule, logicSQL.getSchema().getMetaData(), logicSQL.getSqlStatementContext(), shardingConditions, props).route(result, rule);
-        shardingStatementValidator.ifPresent(validator -> validator.postValidate(sqlStatement, result));
+        validator.ifPresent(v -> v.postValidate(sqlStatement, result));
         return result;
     }
     

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/ddl/AlterIndexStatementHandler.java

@@ -27,16 +27,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.sqlserver.ddl.
 import java.util.Optional;
 
 /**
- * AlterIndexStatement handler for different dialect SQLStatements.
+ * Alter index statement handler for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class AlterIndexStatementHandler {
     
     /**
-     * Get SimpleTableSegment.
+     * Get simple table segment.
      *
-     * @param alterIndexStatement AlterIndexStatement
-     * @return SimpleTableSegment
+     * @param alterIndexStatement alter index statement
+     * @return simple table segment
      */
     public static Optional<SimpleTableSegment> getSimpleTableSegment(final AlterIndexStatement alterIndexStatement) {
         if (alterIndexStatement instanceof SQLServerStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/ddl/CreateTableStatementHandler.java

@@ -26,16 +26,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.Pos
 import org.apache.shardingsphere.sql.parser.sql.dialect.statement.postgresql.ddl.PostgreSQLCreateTableStatement;
 
 /**
- * CreateTableStatement handler for different dialect SQLStatements.
+ * Create table statement handler for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class CreateTableStatementHandler {
-
+    
     /**
-     * Judge whether contains NotExistClause.
+     * Judge whether contains not exist clause.
      *
-     * @param createTableStatement CreateTableStatement
-     * @return whether contains NotExistClause
+     * @param createTableStatement create table statement
+     * @return contains not exist clause or not
      */
     public static boolean containsNotExistClause(final CreateTableStatement createTableStatement) {
         if (createTableStatement instanceof MySQLStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/ddl/DropIndexStatementHandler.java

@@ -29,16 +29,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.sqlserver.ddl.
 import java.util.Optional;
 
 /**
- * DropIndexStatement handler for different dialect SQLStatements.
+ * Drop index statement handler for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class DropIndexStatementHandler {
     
     /**
-     * Get SimpleTableSegment.
+     * Get simple table segment.
      *
-     * @param dropIndexStatement DropIndexStatement
-     * @return SimpleTableSegment
+     * @param dropIndexStatement drop index statement
+     * @return simple table segment
      */
     public static Optional<SimpleTableSegment> getSimpleTableSegment(final DropIndexStatement dropIndexStatement) {
         if (dropIndexStatement instanceof MySQLStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/dml/DeleteStatementHandler.java

@@ -28,16 +28,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.mysql.dml.MySQ
 import java.util.Optional;
 
 /**
- * DeleteStatement handler for different dialect SQLStatements.
+ * Delete statement handler for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class DeleteStatementHandler {
-
+    
     /**
-     * Get OrderBySegment.
+     * Get order by segment.
      *
-     * @param deleteStatement DeleteStatement
-     * @return OrderBySegment
+     * @param deleteStatement delete statement
+     * @return order by segment
      */
     public static Optional<OrderBySegment> getOrderBySegment(final DeleteStatement deleteStatement) {
         if (deleteStatement instanceof MySQLStatement) {
@@ -45,12 +45,12 @@ public final class DeleteStatementHandler {
         }
         return Optional.empty();
     }
-
+    
     /**
-     * Get LimitSegment.
+     * Get limit segment.
      *
-     * @param deleteStatement DeleteStatement
-     * @return LimitSegment
+     * @param deleteStatement delete statement
+     * @return limit segment
      */
     public static Optional<LimitSegment> getLimitSegment(final DeleteStatement deleteStatement) {
         if (deleteStatement instanceof MySQLStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/dml/InsertStatementHandler.java

@@ -34,16 +34,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.sqlserver.dml.
 import java.util.Optional;
 
 /**
- * InsertStatement handler for different dialect SQLStatements.
+ * Insert statement handler for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class InsertStatementHandler {
     
     /**
-     * Get OnDuplicateKeyColumnsSegment.
+     * Get On duplicate key columns segment.
      *
-     * @param insertStatement InsertStatement
-     * @return OnDuplicateKeyColumnsSegment
+     * @param insertStatement insert statement
+     * @return on duplicate key columns segment
      */
     public static Optional<OnDuplicateKeyColumnsSegment> getOnDuplicateKeyColumnsSegment(final InsertStatement insertStatement) {
         if (insertStatement instanceof MySQLStatement) {
@@ -53,10 +53,10 @@ public final class InsertStatementHandler {
     }
     
     /**
-     * Get SetAssignmentSegment.
+     * Get set assignment segment.
      *
-     * @param insertStatement InsertStatement
-     * @return SetAssignmentSegment
+     * @param insertStatement insert statement
+     * @return set assignment segment
      */
     public static Optional<SetAssignmentSegment> getSetAssignmentSegment(final InsertStatement insertStatement) {
         if (insertStatement instanceof MySQLStatement) {
@@ -66,10 +66,10 @@ public final class InsertStatementHandler {
     }
     
     /**
-     * Get WithSegment.
+     * Get with segment.
      *
-     * @param insertStatement InsertStatement
-     * @return WithSegment
+     * @param insertStatement insert statement
+     * @return with segment
      */
     public static Optional<WithSegment> getWithSegment(final InsertStatement insertStatement) {
         if (insertStatement instanceof PostgreSQLStatement) {
@@ -82,10 +82,10 @@ public final class InsertStatementHandler {
     }
     
     /**
-     * Get OutputSegment.
+     * Get output segment.
      * 
-     * @param insertStatement InsertStatement
-     * @return OutputSegment
+     * @param insertStatement insert statement
+     * @return output segment
      */
     public static Optional<OutputSegment> getOutputSegment(final InsertStatement insertStatement) {
         if (insertStatement instanceof SQLServerStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/dml/SelectStatementHandler.java

@@ -36,16 +36,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.sqlserver.dml.
 import java.util.Optional;
 
 /**
- * SelectStatement helper class for different dialect SQLStatements.
+ * Select statement helper class for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class SelectStatementHandler {
 
     /**
-     * Get LimitSegment.
+     * Get limit segment.
      *
-     * @param selectStatement SelectStatement
-     * @return LimitSegment
+     * @param selectStatement select statement
+     * @return limit segment
      */
     public static Optional<LimitSegment> getLimitSegment(final SelectStatement selectStatement) {
         if (selectStatement instanceof MySQLStatement) {
@@ -64,10 +64,10 @@ public final class SelectStatementHandler {
     }
 
     /**
-     * Get LockSegment.
+     * Get lock segment.
      *
-     * @param selectStatement SelectStatement
-     * @return LockSegment
+     * @param selectStatement select statement
+     * @return lock segment
      */
     public static Optional<LockSegment> getLockSegment(final SelectStatement selectStatement) {
         if (selectStatement instanceof MySQLStatement) {

shardingsphere-sql-parser/shardingsphere-sql-parser-statement/src/main/java/org/apache/shardingsphere/sql/parser/sql/dialect/handler/dml/UpdateStatementHandler.java

@@ -28,16 +28,16 @@ import org.apache.shardingsphere.sql.parser.sql.dialect.statement.mysql.dml.MySQ
 import java.util.Optional;
 
 /**
- * UpdateStatement helper class for different dialect SQLStatements.
+ * Update statement helper class for different dialect SQL statements.
  */
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public final class UpdateStatementHandler {
 
     /**
-     * Get OrderBySegment.
+     * Get order by segment.
      *
-     * @param updateStatement UpdateStatement
-     * @return OrderBySegment
+     * @param updateStatement update statement
+     * @return order by segment
      */
     public static Optional<OrderBySegment> getOrderBySegment(final UpdateStatement updateStatement) {
         if (updateStatement instanceof MySQLStatement) {
@@ -47,10 +47,10 @@ public final class UpdateStatementHandler {
     }
 
     /**
-     * Get LimitSegment.
+     * Get limit segment.
      *
-     * @param updateStatement UpdateStatement
-     * @return LimitSegment
+     * @param updateStatement update statement
+     * @return limit segment
      */
     public static Optional<LimitSegment> getLimitSegment(final UpdateStatement updateStatement) {
         if (updateStatement instanceof MySQLStatement) {