com.hazelcast.org.apache.calcite.rel.metadata.MetadataDef 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.Pair;
import com.hazelcast.com.google.common.collect.ImmutableList;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.List;
/**
* Definition of metadata.
*
* @param Kind of metadata
*/
public class MetadataDef {
public final Class metadataClass;
public final Class> handlerClass;
public final ImmutableList methods;
private MetadataDef(Class metadataClass,
Class> handlerClass, Method... methods) {
this.metadataClass = metadataClass;
this.handlerClass = handlerClass;
this.methods = ImmutableList.copyOf(methods);
final Method[] handlerMethods = handlerClass.getDeclaredMethods();
// Handler must have the same methods as Metadata, each method having
// additional "subclass-of-RelNode, RelMetadataQuery" parameters.
assert handlerMethods.length == methods.length;
for (Pair pair : Pair.zip(methods, handlerMethods)) {
final List> leftTypes =
Arrays.asList(pair.left.getParameterTypes());
final List> rightTypes =
Arrays.asList(pair.right.getParameterTypes());
assert leftTypes.size() + 2 == rightTypes.size();
assert RelNode.class.isAssignableFrom(rightTypes.get(0));
assert RelMetadataQuery.class == rightTypes.get(1);
assert leftTypes.equals(rightTypes.subList(2, rightTypes.size()));
}
}
/** Creates a {@link com.hazelcast.org.apache.calcite.rel.metadata.MetadataDef}. */
public static MetadataDef of(Class metadataClass,
Class> handlerClass, Method... methods) {
return new MetadataDef<>(metadataClass, handlerClass, methods);
}
}