/*
 * 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.iotdb.db.queryengine.plan.relational.planner.assertions;

/**
 * An implementation of ExpectedValueProvider should hold the values and SymbolAliases needed to
 * call T's constructor, and call SymbolAlias.toSymbol() to get actual Symbols to pass to T's
 * constructor. Doing this ensures that changes to T's .equals() method that requires a change to
 * T's constructor result in a compilation error.
 *
 * <p>In particular, if adding a new field to T's .equals() method requires passing a value for that
 * field to T's constuctor, using an ExpectedValueProvider that calls T's constructor will ensure
 * that there is a compilation error to be fixed. By contrast, implementing the comparison logic in
 * the test code and using SymbolAliases directly will likely cause tests to pass erroneously
 * without any notification.
 */
public interface ExpectedValueProvider<T> {
  T getExpectedValue(SymbolAliases aliases);
}
