/*
* 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.eigenbase.relopt;
/**
* Provides library users a way to store data within the planner session and
* access it within rules. Frameworks can implement their own implementation
* of Context and pass that as part of the FrameworkConfig.
*/
public interface Context {
/**
* If assignable to clazz, provide the underlying clazz.
* @param clazz The Class object of the desired class.
* @return Underlying object if matches, otherwise null.
*/
<T> T unwrap(Class<T> clazz);
}