Safely casting long to int in Java

casting, java

Solution

A method was added in Java 8:

import static java.lang.Math.toIntExact;

long foo = 10L;
int bar = toIntExact(foo);

Will throw an `ArithmeticException` in case of overflow.

See: `Math.toIntExact(long)`

Several other overflow safe methods have been added to Java 8. They end with exact.

Examples:

- `Math.incrementExact(long)`

- `Math.subtractExact(long, long)`

- `Math.decrementExact(long)`

- `Math.negateExact(long),`

- `Math.subtractExact(int, int)`

Problem

What's the most idiomatic way in Java to verify that a cast from `long` to `int` does not lose any information? This is my current implementation: ``` public static int safeLongToInt(long l) { int i = (int)l; if ((long)i != l) { throw new IllegalArgumentException(l + " cannot be cast to int without changing its value."); } return i; } ```

Original source