hazelcast-master/hazelcast-sql/src/main/java/com/hazelcast/jet/sql/impl/opt/metadata/HazelcastRelMdRowCount.java
/*
 * Copyright 2023 Hazelcast Inc.
 *
 * Licensed under the Hazelcast Community License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://hazelcast.com/hazelcast-community-license
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hazelcast.jet.sql.impl.opt.metadata;

import org.apache.calcite.rel.metadata.ReflectiveRelMetadataProvider;
import org.apache.calcite.rel.metadata.RelMdRowCount;
import org.apache.calcite.rel.metadata.RelMetadataProvider;
import org.apache.calcite.util.BuiltInMethod;

/**
 * Metadata which provides row count estimates.
 */
public final class HazelcastRelMdRowCount extends RelMdRowCount {
    /** Do not change the name (see {@code RelMetadataQueryBase} JavaDoc). */
    public static final RelMetadataProvider SOURCE =
            ReflectiveRelMetadataProvider.reflectiveSource(BuiltInMethod.ROW_COUNT.method, new HazelcastRelMdRowCount());

    private HazelcastRelMdRowCount() {
        // No-op.
    }

    // Empty at the moment, will be extended in the future.
    // Now it serves as an example of how to wire up a metadata handler into Calcite.
}
