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* distributed with this work for additional information
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* 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
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package org.apache.samza.sql.interfaces;

import java.util.Collection;
import org.apache.calcite.rel.RelRoot;


/**
 * Samza SQL Application uses {@link DslConverter} to convert the input dsl to Calcite logical plan.
 */
public interface DslConverter {

  /**
   * Convert the dsl into the Calcite logical plan.
   * @param dsl String containing one or more dsl queries.
   * @return List of Root nodes of the Calcite logical plan.
   * If DSL represents multiple SQL statements. You might return root nodes one for each SQL statement.
   */
  Collection<RelRoot> convertDsl(String dsl);
}