com.hazelcast.org.apache.calcite.rel.metadata.MetadataHandlerProvider 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 com.hazelcast.org.apache.calcite.rel.metadata;
import com.hazelcast.org.apache.calcite.rel.RelNode;
import com.hazelcast.org.apache.calcite.util.ControlFlowException;
/**
* Provides {@link MetadataHandler} call sites for
* {@link RelMetadataQuery}. The handlers provided are responsible for
* updating the cache stored in {@link RelMetadataQuery}.
*/
public interface MetadataHandlerProvider {
/**
* Provide a handler for the requested metadata class.
* @param handlerClass The handler interface expected
* @param The metadata type the handler relates to.
* @return The handler implementation.
*/
> MH handler(Class handlerClass);
/** Re-generates the handler for a given kind of metadata. */
/**
* Revise the handler for a given kind of metadata.
*
* Should be invoked if the existing handler throws a {@link NoHandler} exception.
*
* @param handlerClass The type of class to revise.
* @param The type metadata the handler provides.
* @return A new handler that should be used instead of any previous handler provided.
*/
default > MH revise(Class handlerClass) {
throw new UnsupportedOperationException("This provider doesn't support handler revision.");
}
/** Exception that indicates there there should be a handler for
* this class but there is not. The action is probably to
* re-generate the handler class. */
class NoHandler extends ControlFlowException {
public final Class relClass;
public NoHandler(Class relClass) {
this.relClass = relClass;
}
}
}