org.apache.kudu.util.DecimalUtil.java Source code

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Here is the source code for org.apache.kudu.util.DecimalUtil.java

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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.kudu.util;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.RoundingMode;

import com.google.common.base.Strings;

import org.apache.kudu.ColumnTypeAttributes;
import org.apache.yetus.audience.InterfaceAudience;

import static org.apache.kudu.Common.DataType;

@InterfaceAudience.Private
public class DecimalUtil {
    public static final int MAX_DECIMAL32_PRECISION = 9;
    public static final int MAX_UNSCALED_DECIMAL32 = 999999999;
    public static final int MIN_UNSCALED_DECIMAL32 = -MAX_UNSCALED_DECIMAL32;
    public static final int DECIMAL32_SIZE = 32 / Byte.SIZE;

    public static final int MAX_DECIMAL64_PRECISION = 18;
    public static final long MAX_UNSCALED_DECIMAL64 = 999999999999999999L;
    public static final long MIN_UNSCALED_DECIMAL64 = -MAX_UNSCALED_DECIMAL64;
    public static final int DECIMAL64_SIZE = 64 / Byte.SIZE;

    public static final int MAX_DECIMAL128_PRECISION = 38;
    public static final BigInteger MAX_UNSCALED_DECIMAL128 = new BigInteger(
            Strings.repeat("9", MAX_DECIMAL128_PRECISION));
    public static final BigInteger MIN_UNSCALED_DECIMAL128 = MAX_UNSCALED_DECIMAL128.negate();
    public static final int DECIMAL128_SIZE = 128 / Byte.SIZE;

    public static final int MAX_DECIMAL_PRECISION = MAX_DECIMAL128_PRECISION;

    /**
     * Given a precision, returns the size of the Decimal in Bytes.
     * @return the size in Bytes.
     */
    public static int precisionToSize(int precision) {
        if (precision <= MAX_DECIMAL32_PRECISION) {
            return DECIMAL32_SIZE;
        } else if (precision <= MAX_DECIMAL64_PRECISION) {
            return DECIMAL64_SIZE;
        } else if (precision <= MAX_DECIMAL128_PRECISION) {
            return DECIMAL128_SIZE;
        } else {
            throw new IllegalArgumentException("Unsupported decimal type precision: " + precision);
        }
    }

    /**
     * Given a precision, returns the smallest unscaled data type.
     * @return the smallest valid DataType.
     */
    public static DataType precisionToDataType(int precision) {
        if (precision <= MAX_DECIMAL32_PRECISION) {
            return DataType.DECIMAL32;
        } else if (precision <= MAX_DECIMAL64_PRECISION) {
            return DataType.DECIMAL64;
        } else if (precision <= MAX_DECIMAL128_PRECISION) {
            return DataType.DECIMAL128;
        } else {
            throw new IllegalArgumentException("Unsupported decimal type precision: " + precision);
        }
    }

    /**
     * Returns the maximum value of a Decimal give a precision and scale.
     * @param precision the precision of the decimal.
     * @param scale the scale of the decimal.
     * @return the maximum decimal value.
     */
    public static BigDecimal maxValue(int precision, int scale) {
        String maxPrecision = Strings.repeat("9", precision);
        return new BigDecimal(new BigInteger(maxPrecision), scale);
    }

    /**
     * Returns the minimum value of a Decimal give a precision and scale.
     * @param precision the precision of the decimal.
     * @param scale the scale of the decimal.
     * @return the minimum decimal value.
     */
    public static BigDecimal minValue(int precision, int scale) {
        return maxValue(precision, scale).negate();
    }

    /**
     * Returns the smallest value of a Decimal give a precision and scale.
     * This value can be useful for incrementing a Decimal.
     * @param scale the scale of the decimal.
     * @return the smallest decimal value.
     */
    public static BigDecimal smallestValue(int scale) {
        return new BigDecimal(BigInteger.ONE, scale);
    }

    /**
     * Attempts to coerce a big decimal to a target precision and scale and
     * returns the result. Throws an {@link IllegalArgumentException} if the value
     * can't be coerced without rounding or exceeding the targetPrecision.
     *
     * @param val the BigDecimal value to coerce.
     * @param targetPrecision the target precision of the coerced value.
     * @param targetScale the target scale of the coerced value.
     * @return the coerced BigDecimal value.
     */
    public static BigDecimal coerce(BigDecimal val, int targetPrecision, int targetScale) {
        if (val.scale() != targetScale) {
            try {
                val = val.setScale(targetScale, RoundingMode.UNNECESSARY);
            } catch (ArithmeticException ex) {
                throw new IllegalArgumentException(
                        "Value scale " + val.scale() + " can't be coerced to target scale " + targetScale + ". ");
            }
        }
        if (val.precision() > targetPrecision) {
            throw new IllegalArgumentException("Value precision " + val.precision()
                    + " (after scale coercion) can't be coerced to target precision " + targetPrecision + ". ");
        }
        return val;
    }

    /**
     * Convenience method to create column type attributes for decimal columns.
     * @param precision the precision.
     * @param scale the scale.
     * @return the column type attributes.
     */
    public static ColumnTypeAttributes typeAttributes(int precision, int scale) {
        return new ColumnTypeAttributes.ColumnTypeAttributesBuilder().precision(precision).scale(scale).build();
    }

}