Java Primitive Pairs

Provides pair classes with the same interface as the Apache Commons Pair classes, but with versions specialized to double, int, and long, allowing users to avoid the cost of working with boxed types. If additional types are needed, More Primitive Pairs includes float, char, byte, and boolean specializations.

To include the library in your project (Java 7+ supported), add the following to your POM:

<project>
...
    <dependencies>
        ...
        <dependency>
            <groupId>net.mintern</groupId>
            <artifactId>primitive-pairs</artifactId>
            <version>1.0</version>
        </dependency>
        ...
    </dependencies>
...
</project>

Sample usage

List<ObjIntPair<String>> enumerated = new ArrayList<>();
int i = 0;
for (String s: myStrings) {
    enumerated.add(ObjIntPair.of(s, i++));
}

Pair types

As with the Apache Commons Pair, each pair type is comprised of a base FooPair, an ImmutableFooPair, and a MutableFooPair. The supported combinations are:

• ObjDoublePair
• ObjLongPair
• ObjIntPair
• DoublePair (two doubles)
• DoubleLongPair
• DoubleIntPair
• LongPair (two longs)
• LongIntPair
• IntLongPair
• IntPair (two ints)

For these four types, this provides all possible combinations. (The ObjPair, of course, is simply Apache's Pair.) If you order the types as Object, Double, Long, Int, then the widest type comes first.

IntLongPair is the only exception to this pattern. Because of the shape of classes like ObjIntPair and DoubleIntPair, a pair that consists of a value and its corresponding index would typically have the index second. Since long can also be used to number sequences, it seemed useful to provide an IntLongPair for numbering a series of int values without reversing the typical (value, index) pattern encouraged by the rest of this library.

Contributing

I will happily accept Pull Requests. If you have any questions, ask away. Please keep changes to a minimum; do not make gratuitous style changes.

Building

In the root directory, run mvn install. That will build everything.

Related projects

All of my Java libraries are available in the mintern-java organization.