content: /*
   * 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.calcite.sql.type;
  
  import org.apache.calcite.rel.type.RelDataType;
  import org.apache.calcite.sql.SqlOperatorBinding;
  
  import com.google.common.collect.ImmutableList;
  
  import org.checkerframework.checker.nullness.qual.Nullable;
  
  import java.util.List;
  
  import static com.google.common.base.Preconditions.checkArgument;
  
  /**
   * Returns the first type that matches a set of given {@link SqlTypeName}s. If
   * no match could be found, null is returned.
   */
  public class MatchReturnTypeInference implements SqlReturnTypeInference {
    //~ Instance fields --------------------------------------------------------
  
    private final int start;
    private final List<SqlTypeName> typeNames;
  
    //~ Constructors -----------------------------------------------------------
  
    /**
     * Returns the first type of typeName at or after position start (zero
     * based).
     *
     * @see #MatchReturnTypeInference(int, SqlTypeName[])
     */
    public MatchReturnTypeInference(int start, SqlTypeName... typeNames) {
      this(start, ImmutableList.copyOf(typeNames));
    }
  
    /**
     * Returns the first type matching any type in typeNames at or after
     * position start (zero based).
     */
    public MatchReturnTypeInference(int start, Iterable<SqlTypeName> typeNames) {
      checkArgument(start >= 0);
      this.start = start;
      this.typeNames = ImmutableList.copyOf(typeNames);
      checkArgument(!this.typeNames.isEmpty());
    }
  
    //~ Methods ----------------------------------------------------------------
  
    @Override public @Nullable RelDataType inferReturnType(
        SqlOperatorBinding opBinding) {
      for (int i = start; i < opBinding.getOperandCount(); i++) {
        RelDataType argType = opBinding.getOperandType(i);
        if (SqlTypeUtil.isOfSameTypeName(typeNames, argType)) {
          return argType;
        }
      }
      return null;
    }
  }
  