for #2567, remove InsertColumns

sharding-core/sharding-core-optimize/src/main/java/org/apache/shardingsphere/core/optimize/api/segment/InsertColumns.java

-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.shardingsphere.core.optimize.api.segment;
-
-import java.util.Collection;
-
-/**
- * Insert columns.
- *
- * @author zhangliang
- */
-public interface InsertColumns {
-    
-    /**
-     * Get regular column names.
-     * 
-     * @return regular column names
-     */
-    Collection<String> getRegularColumnNames();
-}

sharding-core/sharding-core-optimize/src/main/java/org/apache/shardingsphere/core/optimize/sharding/segment/insert/ShardingInsertColumns.java

@@ -21,7 +21,6 @@ import com.google.common.base.Optional;
 import lombok.Getter;
 import lombok.ToString;
 import org.apache.shardingsphere.core.metadata.table.TableMetas;
-import org.apache.shardingsphere.core.optimize.api.segment.InsertColumns;
 import org.apache.shardingsphere.core.parse.sql.statement.dml.InsertStatement;
 import org.apache.shardingsphere.core.rule.ShardingRule;
 
@@ -35,7 +34,7 @@ import java.util.LinkedHashSet;
  * @author panjuan
  */
 @ToString
-public final class ShardingInsertColumns implements InsertColumns {
+public final class ShardingInsertColumns {
     
     @Getter
     private final Collection<String> regularColumnNames;