sdks/java/extensions/sql/zetasql/src/main/java/org/apache/beam/sdk/extensions/sql/zetasql/translation/SingleRowScanConverter.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
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package org.apache.beam.sdk.extensions.sql.zetasql.translation;

import com.google.zetasql.resolvedast.ResolvedNodes.ResolvedSingleRowScan;
import java.util.List;
import org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rel.RelNode;

/** Converts a single row value. */
class SingleRowScanConverter extends RelConverter<ResolvedSingleRowScan> {

  SingleRowScanConverter(ConversionContext context) {
    super(context);
  }

  @Override
  public boolean canConvert(ResolvedSingleRowScan zetaNode) {
    return zetaNode.getColumnList() == null || zetaNode.getColumnList().isEmpty();
  }

  @Override
  public RelNode convert(ResolvedSingleRowScan zetaNode, List<RelNode> inputs) {
    return createOneRow(getCluster());
  }
}