org.apache.drill.exec.expr.fn.DrillDecimalCastFuncHolder Maven / Gradle / Ivy

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/**
 * 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.drill.exec.expr.fn;

import java.util.List;

import org.apache.drill.common.exceptions.DrillRuntimeException;
import org.apache.drill.common.expression.LogicalExpression;
import org.apache.drill.common.expression.ValueExpressions;
import org.apache.drill.common.types.TypeProtos;
import org.apache.drill.common.types.TypeProtos.MajorType;
import org.apache.drill.exec.expr.annotations.FunctionTemplate.NullHandling;

public class DrillDecimalCastFuncHolder extends DrillSimpleFuncHolder {

  public DrillDecimalCastFuncHolder(FunctionAttributes functionAttributes, FunctionInitializer initializer) {
    super(functionAttributes, initializer);
  }

    @Override
    public MajorType getReturnType(List args) {

        TypeProtos.DataMode mode = returnValue.type.getMode();

        if (nullHandling == NullHandling.NULL_IF_NULL) {
            // if any one of the input types is nullable, then return nullable return type
            for (LogicalExpression e : args) {
                if (e.getMajorType().getMode() == TypeProtos.DataMode.OPTIONAL) {
                    mode = TypeProtos.DataMode.OPTIONAL;
                    break;
                }
            }
        }

        if (args.size() != 3) {
            StringBuilder err = new StringBuilder();
            for (int i = 0; i < args.size(); i++) {
                err.append("arg" + i + ": " + args.get(i).getMajorType().getMinorType());
            }
            throw new DrillRuntimeException("Decimal cast function invoked with incorect arguments" + err);
        }

        int scale = (int) ((ValueExpressions.LongExpression)(args.get(args.size() - 1))).getLong();
        int precision = (int) ((ValueExpressions.LongExpression)(args.get(args.size() - 2))).getLong();
        return (TypeProtos.MajorType.newBuilder().setMinorType(returnValue.type.getMinorType()).setScale(scale).setPrecision(precision).setMode(mode).build());
    }
}