Java BigDecimal to toScientificNotation(BigDecimal bd)

Description

Formats a BigDecimal value to a string in scientific notation For example

• A value of 0.00001234 would be formated as 1.234E-5
• A value of 100000.00 would be formated as 1.00E5
• A value of 100 (scale zero) would be formated as 1E2

If bd has a precision higher than 20, this method will truncate the output string to have a precision of 20 (no rounding will be done, just a truncate).

License

Apache License

Declaration

public static String toScientificNotation(BigDecimal bd) 

Method Source Code

//package com.java2s;
/*/*from   w ww .j a v  a2s . c om*/
 // Licensed to DynamoBI Corporation (DynamoBI) under one
 // or more contributor license agreements.  See the NOTICE file
 // distributed with this work for additional information
 // regarding copyright ownership.  DynamoBI 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.
 */

import java.math.*;

public class Main {
    /**
     * Formats a {@link BigDecimal} value to a string in scientific notation For
     * example<br>
     *
     * <ul>
     * <li>A value of 0.00001234 would be formated as <code>1.234E-5</code></li>
     * <li>A value of 100000.00 would be formated as <code>1.00E5</code></li>
     * <li>A value of 100 (scale zero) would be formated as <code>
     * 1E2</code></li><br>
     * If <code>bd</code> has a precision higher than 20, this method will
     * truncate the output string to have a precision of 20 (no rounding will be
     * done, just a truncate).
     */
    public static String toScientificNotation(BigDecimal bd) {
        final int truncateAt = 20;
        String unscaled = bd.unscaledValue().toString();
        if (bd.signum() < 0) {
            unscaled = unscaled.substring(1);
        }
        int len = unscaled.length();
        int scale = bd.scale();
        int e = len - scale - 1;

        StringBuilder ret = new StringBuilder();
        if (bd.signum() < 0) {
            ret.append('-');
        }

        //do truncation
        unscaled = unscaled.substring(0, Math.min(truncateAt, len));
        ret.append(unscaled.charAt(0));
        if (scale == 0) {
            // trim trailing zeroes since they aren't significant
            int i = unscaled.length();
            while (i > 1) {
                if (unscaled.charAt(i - 1) != '0') {
                    break;
                }
                --i;
            }
            unscaled = unscaled.substring(0, i);
        }
        if (unscaled.length() > 1) {
            ret.append(".");
            ret.append(unscaled.substring(1));
        }

        ret.append("E");
        ret.append(e);
        return ret.toString();
    }
}

Related

1. toLong(BigDecimal value)
2. toLongObject(@Nullable final BigDecimal value)
3. toNumber(final BigDecimal bigDecimal, final Class clazz)
4. toObject(BigDecimal value)
5. toPercent(final BigDecimal decimalValue, final MathContext mathCntext)
6. toSimpleBigDecimal(Object num)
7. toString(BigDecimal num)
8. toString(BigDecimal value, int numberDecimalPlaces)
9. toString(final BigDecimal dec)