/*
* 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 com.aliyun.odps.lot.common;
import apsara.odps.lot.ExpressionProtos;
/**
* 值表达式. null reference == NULL constant.
*/
public abstract class ScalarExpression {
public abstract ExpressionProtos.ScalarExpression toProtoBuf();
public static ExpressionProtos.ScalarExpression genNull() {
apsara.odps.ExpressionProtos.Null.Builder n = apsara.odps.ExpressionProtos.Null.newBuilder();
ExpressionProtos.ScalarExpression.Builder
builder =
ExpressionProtos.ScalarExpression.newBuilder();
builder.setNull(n.build());
return builder.build();
}
}