Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.math.BigDecimal;

/* 
 * 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.
 *
 *
 */
public class Main {

    /**
     * Subtract two long integers, checking for overflow.
     * 
     * @param a first value
     * @param b second value
     * @return the difference <code>a-b</code>
     * @throws ArithmeticException if the result can not be represented as an
     *         long
     * @since 1.2
     */
    public static long subAndCheck(long a, long b) {
        long ret;
        String msg = "overflow: subtract";
        if (b == Long.MIN_VALUE) {
            if (a < 0) {
                ret = a - b;
            } else {
                throw new ArithmeticException(msg);
            }
        } else {
            // use additive inverse
            ret = addAndCheck(a, -b, msg);
        }
        return ret;
    }

    /**
     * Add two long integers, checking for overflow.
     * 
     * @param a an addend
     * @param b an addend
     * @param msg the message to use for any thrown exception.
     * @return the sum <code>a+b</code>
     * @throws ArithmeticException if the result can not be represented as an
     *         long
     * @since 1.2
     */
    private static long addAndCheck(long a, long b, String msg) {
        long ret;
        if (a > b) {
            // use symmetry to reduce boundry cases
            ret = addAndCheck(b, a, msg);
        } else {
            // assert a <= b

            if (a < 0) {
                if (b < 0) {
                    // check for negative overflow
                    if (Long.MIN_VALUE - b <= a) {
                        ret = a + b;
                    } else {
                        throw new ArithmeticException(msg);
                    }
                } else {
                    // oppisite sign addition is always safe
                    ret = a + b;
                }
            } else {
                // assert a >= 0
                // assert b >= 0

                // check for positive overflow
                if (a <= Long.MAX_VALUE - b) {
                    ret = a + b;
                } else {
                    throw new ArithmeticException(msg);
                }
            }
        }
        return ret;
    }
}