com.hazelcast.org.apache.calcite.sql.fun.SqlThrowOperator Maven / Gradle / Ivy
/*
* 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.hazelcast.org.apache.calcite.sql.fun;
import com.hazelcast.org.apache.calcite.sql.SqlCall;
import com.hazelcast.org.apache.calcite.sql.SqlKind;
import com.hazelcast.org.apache.calcite.sql.SqlSpecialOperator;
import com.hazelcast.org.apache.calcite.sql.SqlWriter;
import com.hazelcast.org.apache.calcite.sql.type.OperandTypes;
import com.hazelcast.org.apache.calcite.sql.type.ReturnTypes;
/**
* An internal operator that throws an exception.
*
* The exception is thrown with a (localized) error message which is the only
* input parameter to the operator.
*
* The return type is defined as a BOOLEAN
to facilitate the use
* of it in constructs such as the following:
*
* CASE
* WHEN <conditionn> THEN true
* ELSE throw("what's wrong with you man?")
* END
*/
public class SqlThrowOperator extends SqlSpecialOperator {
//~ Constructors -----------------------------------------------------------
public SqlThrowOperator() {
super(
"$throw",
SqlKind.OTHER,
2,
true,
ReturnTypes.BOOLEAN,
null,
OperandTypes.CHARACTER);
}
//~ Methods ----------------------------------------------------------------
public void unparse(
SqlWriter writer,
SqlCall call,
int leftPrec,
int rightPrec) {
final SqlWriter.Frame frame = writer.startFunCall(getName());
call.operand(0).unparse(writer, 0, 0);
writer.endFunCall(frame);
}
}