org.apache.flink.table.planner.typeutils.RowTypeUtils Maven / Gradle / Ivy

/*
 * 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.flink.table.planner.typeutils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/** Utils for deriving row types of {@link org.apache.calcite.rel.RelNode}s. */
public class RowTypeUtils {

    public static String getUniqueName(String oldName, List checklist) {
        return getUniqueName(Collections.singletonList(oldName), checklist).get(0);
    }

    public static List getUniqueName(List oldNames, List checklist) {
        List result = new ArrayList<>();
        for (String oldName : oldNames) {
            if (checklist.contains(oldName) || result.contains(oldName)) {
                int suffix = -1;
                String changedName;
                do {
                    suffix++;
                    changedName = oldName + "_" + suffix;
                } while (checklist.contains(changedName) || result.contains(changedName));
                result.add(changedName);
            } else {
                result.add(oldName);
            }
        }
        return result;
    }
}