Recipe 0.1. Creating Interval

You want to create an interval of numbers.

Here lie some definitions for interval:

An interval is a set of reals with the property that any number that lies between two numbers is included in the set.

An interval is said to be opened ("[]"), closed ("][")or semi-opened ("[[" or "]]") depending on the possible inclusion of bounds. For example, the set of all numbers x satisfying 0 ≤ x < 1 is a semi-opened interval [0, 1[ which contains 0 and not 1, as well as all numbers between them.

In the JPL, all intervals by default are semi-opened.

Here is a code that build a default interval:

// default interval: [a, b[
Interval interval = new Interval.Builder(245.56, 310).build();

Assert.assertTrue(interval.contains(263));

It is also possible to include or exclude boundaries:

// interval: ]a, b]
Interval interval = new Interval.Builder(0, 10)
	.excludeLowerBound().includeUpperBound().build();

Assert.assertFalse(interval.contains(0));

See also the recipe about creating domain of definition.