samza-sql/src/main/java/org/apache/samza/sql/planner/SamzaSqlUdfOperatorTable.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.samza.sql.planner;

import java.util.List;
import java.util.stream.Collectors;
import org.apache.calcite.sql.SqlFunctionCategory;
import org.apache.calcite.sql.SqlIdentifier;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.SqlOperatorTable;
import org.apache.calcite.sql.SqlSyntax;
import org.apache.calcite.sql.parser.SqlParserPos;
import org.apache.calcite.sql.util.ListSqlOperatorTable;
import org.apache.calcite.sql.validate.SqlUserDefinedFunction;
import org.apache.samza.sql.interfaces.UdfMetadata;


public class SamzaSqlUdfOperatorTable implements SqlOperatorTable {

  private final ListSqlOperatorTable operatorTable;

  public SamzaSqlUdfOperatorTable(List<SamzaSqlScalarFunctionImpl> scalarFunctions) {
    operatorTable = new ListSqlOperatorTable(getSqlOperators(scalarFunctions));
  }

  private List<SqlOperator> getSqlOperators(List<SamzaSqlScalarFunctionImpl> scalarFunctions) {
    return scalarFunctions.stream().map(this::getSqlOperator).collect(Collectors.toList());
  }

  private SqlOperator getSqlOperator(SamzaSqlScalarFunctionImpl scalarFunction) {
    int numArguments = scalarFunction.numberOfArguments();
    UdfMetadata udfMetadata = scalarFunction.getUdfMetadata();

    if(udfMetadata.isDisableArgCheck()) {
      return new SqlUserDefinedFunction(new SqlIdentifier(scalarFunction.getUdfName(), SqlParserPos.ZERO),
          o -> scalarFunction.getReturnType(o.getTypeFactory()), null, Checker.ANY_CHECKER,
          null, scalarFunction);
    } else {
      return new SqlUserDefinedFunction(new SqlIdentifier(scalarFunction.getUdfName(), SqlParserPos.ZERO),
          o -> scalarFunction.getReturnType(o.getTypeFactory()), null, Checker.getChecker(numArguments, numArguments),
          null, scalarFunction);
    }
  }

  @Override
  public void lookupOperatorOverloads(SqlIdentifier opName, SqlFunctionCategory category, SqlSyntax syntax,
      List<SqlOperator> operatorList) {
    SqlIdentifier upperCaseOpName = opName;
    // Only udfs are case insensitive
    if (category != null && category.equals(SqlFunctionCategory.USER_DEFINED_FUNCTION)) {
      upperCaseOpName = new SqlIdentifier(opName.names.get(0).toUpperCase(), opName.getComponentParserPosition(0));
    }
    operatorTable.lookupOperatorOverloads(upperCaseOpName, category, syntax, operatorList);
  }

  @Override
  public List<SqlOperator> getOperatorList() {
    return operatorTable.getOperatorList();
  }
}