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;
  
  /**
   * Strategy to transform one type to another. The transformation is dependent on
   * the implemented strategy object and in the general case is a function of the
   * type and the other operands. Can not be used by itself. Must be used in an
   * object of type {@link SqlTypeTransformCascade}.
   *
   * <p>This class is an example of the
   * {@link org.apache.calcite.util.Glossary#STRATEGY_PATTERN strategy pattern}.
   *
   * @see SqlTypeTransforms
   */
  public interface SqlTypeTransform {
    //~ Methods ----------------------------------------------------------------
  
    /**
     * Transforms a type.
     *
     * @param opBinding       call context in which transformation is being
     *                        performed
     * @param typeToTransform type to be transformed, never null
     * @return transformed type, never null
     */
    RelDataType transformType(
        SqlOperatorBinding opBinding,
        RelDataType typeToTransform);
  
    /** Creates an operand type transform. */
    default SqlOperatorBinding apply(SqlOperatorBinding operatorBinding) {
      return operatorBinding.transform(this);
    }
  }
  