isabella232 / de.flapdoodle.guava

minor guava extensions

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de.flapdoodle.guava

minor guava extensions

Maven

Stable (Maven Central Repository, Released: 09.08.2016 - wait 24hrs for maven central)

<dependency>
	<groupId>de.flapdoodle.guava</groupId>
	<artifactId>de.flapdoodle.guava</artifactId>
	<version>1.4.1</version>
</dependency>

Snapshots (Repository http://oss.sonatype.org/content/repositories/snapshots)

<dependency>
	<groupId>de.flapdoodle.guava</groupId>
	<artifactId>de.flapdoodle.guava</artifactId>
	<version>1.4.2-SNAPSHOT</version>
</dependency>

Usage

We did some minor extensions based on guava stuff which can be usefull in some situations. These extensions are not optimized for speed or memory usage.

Collections stuff

First element of collections

List<String> data;
...
Optional<String> result = Expectations.noneOrOne(data);
...

Convert lists into maps

Convert a list into a 1:1 map

List<Order> orders;
...
Function<Order, Integer> keytransformation = new Function<Order, Integer>() {

	@Override
	public Integer apply(Order order) {
		return order.getId();
	}
};

Map<Integer, Order> orderMap = Transformations.map(orders, keytransformation);

Order order = orderMap.get(2);
...

Convert a list into a 1:1 map with transformations for key and value

List<User> users;
...
Function<User, Integer> keytransformation = new Function<User, Integer>() {

	@Override
	public Integer apply(User user) {
		return user.id();
	}
};

Function<User, String> valuetransformation = new Function<User, String>() {

	@Override
	public String apply(User user) {
		return user.name();
	}
};

Map<Integer, String> userMap = Transformations.map(users, keytransformation, valuetransformation);

String userName = userMap.get(2);
...

Convert a list into a map of lists

...
List<String> names = Lists.newArrayList("Achim", "Albert", "Susi", "Sonja", "Bert");

Function<String, Character> keytransformation = new Function<String, Character>() {

	@Override
	public Character apply(String name) {
		return name.charAt(0);
	}
};

Map<Character, ImmutableList<? extends String>> nameMap = Transformations.map(names, keytransformation,
		Folds.asListFold(Transformations.<String> asCollection()));

ImmutableList<? extends String> namesWithA = nameMap.get('A');

...

Foldleft

foldLeft can be used for many aggregation operations like sum, count, concat.. ... List numbers = Lists.newArrayList(1,2,3,4,5,6); int result = Folds.foldLeft(numbers, new Foldleft<Integer, Integer>() { @Override public Integer apply(Integer left, Integer right) { return left+right; } }, 0);

...