content: /*
   * 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.beam.sdk.extensions.sql.impl.cep;
  
  import java.io.Serializable;
  import org.apache.beam.sdk.extensions.sql.impl.SqlConversionException;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexCall;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexLiteral;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexNode;
  import org.apache.beam.vendor.calcite.v1_40_0.org.apache.calcite.rex.RexPatternFieldRef;
  
  /**
   * {@code CEPOperation} is the base class for the evaluation operations defined in the {@code
   * DEFINE} syntax of {@code MATCH_RECOGNIZE}. {@code CEPCall}, {@code CEPFieldRef}, {@code
   * CEPLiteral} are the subclasses of it.
   */
  public abstract class CEPOperation implements Serializable {
  
    public static CEPOperation of(RexNode operation) {
      if (operation.getClass() == RexCall.class) {
        RexCall call = (RexCall) operation;
        return CEPCall.of(call);
      } else if (operation.getClass() == RexLiteral.class) {
        RexLiteral lit = (RexLiteral) operation;
        return CEPLiteral.of(lit);
      } else if (operation.getClass() == RexPatternFieldRef.class) {
        RexPatternFieldRef fieldRef = (RexPatternFieldRef) operation;
        return CEPFieldRef.of(fieldRef);
      } else {
        throw new SqlConversionException("RexNode not supported: " + operation.getClass().getName());
      }
    }
  }
  