Jdk8Methods.java
/*
* Copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of JSR-310 nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.threeten.bp.jdk8;
/**
* A set of utility methods that provide additional functionality for working
* with dates and times.
* <p>
* The contents of this class replace functionality available in JDK 8.
*
* <h3>Specification for implementors</h3>
* This is a thread-safe utility class.
* All returned classes are immutable and thread-safe.
*/
public final class Jdk8Methods {
/**
* Private constructor since this is a utility class.
*/
private Jdk8Methods() {
}
//-----------------------------------------------------------------------
/**
* Ensures that the argument is non-null.
*
* @param <T> the value type
* @param value the value to check
* @return the checked non-null value
* @throws NullPointerException if the value is null
*/
public static <T> T requireNonNull(T value) {
if (value == null) {
throw new NullPointerException("Value must not be null");
}
return value;
}
/**
* Ensures that the argument is non-null.
*
* @param <T> the value type
* @param value the value to check
* @param parameterName the name of the parameter
* @return the checked non-null value
* @throws NullPointerException if the value is null
*/
public static <T> T requireNonNull(T value, String parameterName) {
if (value == null) {
throw new NullPointerException(parameterName + " must not be null");
}
return value;
}
//-----------------------------------------------------------------------
/**
* Compares two objects.
*
* @param a the first value
* @param b the second value
* @return the result
*/
public static boolean equals(Object a, Object b) {
if (a == null) {
return b == null;
}
if (b == null) {
return false;
}
return a.equals(b);
}
/**
* Compares two ints.
*
* @param a the first value
* @param b the second value
* @return the result
*/
public static int compareInts(int a, int b) {
if (a < b) {
return -1;
}
if (a > b) {
return 1;
}
return 0;
}
/**
* Compares two longs.
*
* @param a the first value
* @param b the second value
* @return the result
*/
public static int compareLongs(long a, long b) {
if (a < b) {
return -1;
}
if (a > b) {
return 1;
}
return 0;
}
//-----------------------------------------------------------------------
/**
* Safely adds two int values.
*
* @param a the first value
* @param b the second value
* @return the result
* @throws ArithmeticException if the result overflows an int
*/
public static int safeAdd(int a, int b) {
int sum = a + b;
// check for a change of sign in the result when the inputs have the same sign
if ((a ^ sum) < 0 && (a ^ b) >= 0) {
throw new ArithmeticException("Addition overflows an int: " + a + " + " + b);
}
return sum;
}
/**
* Safely adds two long values.
*
* @param a the first value
* @param b the second value
* @return the result
* @throws ArithmeticException if the result overflows a long
*/
public static long safeAdd(long a, long b) {
long sum = a + b;
// check for a change of sign in the result when the inputs have the same sign
if ((a ^ sum) < 0 && (a ^ b) >= 0) {
throw new ArithmeticException("Addition overflows a long: " + a + " + " + b);
}
return sum;
}
//-----------------------------------------------------------------------
/**
* Safely subtracts one int from another.
*
* @param a the first value
* @param b the second value to subtract from the first
* @return the result
* @throws ArithmeticException if the result overflows an int
*/
public static int safeSubtract(int a, int b) {
int result = a - b;
// check for a change of sign in the result when the inputs have the different signs
if ((a ^ result) < 0 && (a ^ b) < 0) {
throw new ArithmeticException("Subtraction overflows an int: " + a + " - " + b);
}
return result;
}
/**
* Safely subtracts one long from another.
*
* @param a the first value
* @param b the second value to subtract from the first
* @return the result
* @throws ArithmeticException if the result overflows a long
*/
public static long safeSubtract(long a, long b) {
long result = a - b;
// check for a change of sign in the result when the inputs have the different signs
if ((a ^ result) < 0 && (a ^ b) < 0) {
throw new ArithmeticException("Subtraction overflows a long: " + a + " - " + b);
}
return result;
}
//-----------------------------------------------------------------------
/**
* Safely multiply one int by another.
*
* @param a the first value
* @param b the second value
* @return the result
* @throws ArithmeticException if the result overflows an int
*/
public static int safeMultiply(int a, int b) {
long total = (long) a * (long) b;
if (total < Integer.MIN_VALUE || total > Integer.MAX_VALUE) {
throw new ArithmeticException("Multiplication overflows an int: " + a + " * " + b);
}
return (int) total;
}
/**
* Safely multiply a long by an int.
*
* @param a the first value
* @param b the second value
* @return the new total
* @throws ArithmeticException if the result overflows a long
*/
public static long safeMultiply(long a, int b) {
switch (b) {
case -1:
if (a == Long.MIN_VALUE) {
throw new ArithmeticException("Multiplication overflows a long: " + a + " * " + b);
}
return -a;
case 0:
return 0L;
case 1:
return a;
}
long total = a * b;
if (total / b != a) {
throw new ArithmeticException("Multiplication overflows a long: " + a + " * " + b);
}
return total;
}
/**
* Multiply two values throwing an exception if overflow occurs.
*
* @param a the first value
* @param b the second value
* @return the new total
* @throws ArithmeticException if the result overflows a long
*/
public static long safeMultiply(long a, long b) {
if (b == 1) {
return a;
}
if (a == 1) {
return b;
}
if (a == 0 || b == 0) {
return 0;
}
long total = a * b;
if (total / b != a || (a == Long.MIN_VALUE && b == -1) || (b == Long.MIN_VALUE && a == -1)) {
throw new ArithmeticException("Multiplication overflows a long: " + a + " * " + b);
}
return total;
}
//-----------------------------------------------------------------------
/**
* Safely convert a long to an int.
*
* @param value the value to convert
* @return the int value
* @throws ArithmeticException if the result overflows an int
*/
public static int safeToInt(long value) {
if (value > Integer.MAX_VALUE || value < Integer.MIN_VALUE) {
throw new ArithmeticException("Calculation overflows an int: " + value);
}
return (int) value;
}
//-----------------------------------------------------------------------
/**
* Returns the floor division.
* <p>
* This returns {@code 0} for {@code floorDiv(0, 4)}.<br />
* This returns {@code -1} for {@code floorDiv(-1, 4)}.<br />
* This returns {@code -1} for {@code floorDiv(-2, 4)}.<br />
* This returns {@code -1} for {@code floorDiv(-3, 4)}.<br />
* This returns {@code -1} for {@code floorDiv(-4, 4)}.<br />
* This returns {@code -2} for {@code floorDiv(-5, 4)}.<br />
*
* @param a the dividend
* @param b the divisor
* @return the floor division
*/
public static long floorDiv(long a, long b) {
return (a >= 0 ? a / b : ((a + 1) / b) - 1);
}
/**
* Returns the floor modulus.
* <p>
* This returns {@code 0} for {@code floorMod(0, 4)}.<br />
* This returns {@code 1} for {@code floorMod(-1, 4)}.<br />
* This returns {@code 2} for {@code floorMod(-2, 4)}.<br />
* This returns {@code 3} for {@code floorMod(-3, 4)}.<br />
* This returns {@code 0} for {@code floorMod(-4, 4)}.<br />
*
* @param a the dividend
* @param b the divisor
* @return the floor modulus (positive)
*/
public static long floorMod(long a, long b) {
return ((a % b) + b) % b;
}
/**
* Returns the floor modulus.
* <p>
* This returns {@code 0} for {@code floorMod(0, 4)}.<br />
* This returns {@code 3} for {@code floorMod(-1, 4)}.<br />
* This returns {@code 2} for {@code floorMod(-2, 4)}.<br />
* This returns {@code 1} for {@code floorMod(-3, 4)}.<br />
* This returns {@code 0} for {@code floorMod(-4, 4)}.<br />
* This returns {@code 3} for {@code floorMod(-5, 4)}.<br />
*
* @param a the dividend
* @param b the divisor
* @return the floor modulus (positive)
*/
public static int floorMod(long a, int b) {
return (int) (((a % b) + b) % b);
}
/**
* Returns the floor division.
* <p>
* This returns {@code 1} for {@code floorDiv(3, 3)}.<br />
* This returns {@code 0} for {@code floorDiv(2, 3)}.<br />
* This returns {@code 0} for {@code floorDiv(1, 3)}.<br />
* This returns {@code 0} for {@code floorDiv(0, 3)}.<br />
* This returns {@code -1} for {@code floorDiv(-1, 3)}.<br />
* This returns {@code -1} for {@code floorDiv(-2, 3)}.<br />
* This returns {@code -1} for {@code floorDiv(-3, 3)}.<br />
* This returns {@code -2} for {@code floorDiv(-4, 3)}.<br />
*
* @param a the dividend
* @param b the divisor
* @return the floor division
*/
public static int floorDiv(int a, int b) {
return (a >= 0 ? a / b : ((a + 1) / b) - 1);
}
/**
* Returns the floor modulus.
* <p>
* This returns {@code 0} for {@code floorMod(3, 3)}.<br />
* This returns {@code 2} for {@code floorMod(2, 3)}.<br />
* This returns {@code 1} for {@code floorMod(1, 3)}.<br />
* This returns {@code 0} for {@code floorMod(0, 3)}.<br />
* This returns {@code 2} for {@code floorMod(-1, 3)}.<br />
* This returns {@code 1} for {@code floorMod(-2, 3)}.<br />
* This returns {@code 0} for {@code floorMod(-3, 3)}.<br />
* This returns {@code 2} for {@code floorMod(-4, 3)}.<br />
*
* @param a the dividend
* @param b the divisor
* @return the floor modulus (positive)
*/
public static int floorMod(int a, int b) {
return ((a % b) + b) % b;
}
}