spark/src/main/java/org/apache/calcite/adapter/spark/SparkRel.java

/*
 * 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.calcite.adapter.spark;

import org.apache.calcite.adapter.enumerable.JavaRelImplementor;
import org.apache.calcite.adapter.enumerable.PhysType;
import org.apache.calcite.linq4j.tree.BlockStatement;
import org.apache.calcite.plan.Convention;
import org.apache.calcite.rel.RelNode;
import org.apache.calcite.rex.RexBuilder;

/**
 * Relational expression that uses Spark calling convention.
 */
public interface SparkRel extends RelNode {
  Result implementSpark(Implementor implementor);

  /** Calling convention for relational operations that occur in Spark. */
  Convention CONVENTION = new Convention.Impl("SPARK", SparkRel.class);

  /** Extension to {@link JavaRelImplementor} that can handle Spark relational
   * expressions. */
  abstract class Implementor extends JavaRelImplementor {
    public Implementor(RexBuilder rexBuilder) {
      super(rexBuilder);
    }

    abstract Result result(PhysType physType, BlockStatement blockStatement);

    abstract Result visitInput(SparkRel parent, int ordinal, SparkRel input);
  }

  /** Result of generating Java code to implement a Spark relational
   * expression. */
  class Result {
    public final BlockStatement block;
    public final PhysType physType;

    public Result(PhysType physType, BlockStatement block) {
      this.physType = physType;
      this.block = block;
    }
  }
}