Hyphen

Java Equivalent of javascript underscore library

The stream api is a cool addition to Java 8 but it's use leads to some verbosity in the code. Underscorejs has a nice api for collection and this is an implementation for those api in java. Language limitations could have restricted the api being slightly different but the name of the method and the functionality provided are retained.

Usage

Data

Employee fooEmployee = new Employee(10, "foo")

Employee barEmployee = new Employee(20, "bar")

Employee bazEmployee = new Employee(30, "baz")

Employee employees = [fooEmployee, barEmployee, bazEmployee]

Examples

• each(employees, Employee::increment) =>

            calls increment for each employee
  

• map(employees, e -> e.getId() * e.getId()) =>

            [100,400,900]
  

• lapply(employees, e -> e.getId()) =>

            [10,20,30]
  

• fold(employees, (e, acc) -> acc + e.getName(), "") =>

            foobarbaz
  

• foldNoReduce(employees, (e, acc) -> acc.add(e.getName()), new ArrayList()) =>

            ["foo","bar","baz"]
  

• reduce(employees, Employee::getId, 0, (a, b) -> a + b) =>

            60
  

• find(employees, e -> e.getName().equals("foo")) =>

            fooEmployee
  

• filter(employees, d -> d.getName().startsWith("ba")) =>

            [barEmployee,bazEmployee]
  

• pluck(employees, Employee::getName) =>

            ["foo", "bar", "baz"]
  

• where(employees, m(kv("id", 10),kv("name", "foo"))) =>

            [fooEmployee]
  

• findWhere(employees, m(kv("id", 10),kv("name", "foo"))) =>

            fooEmployee
  

• reject(employees, e -> e.getName().equals("bar)) =>

            [fooEmployee,bazEmployee]
  

• every(employees, d -> d.getId() >= 10)

            true
  

• some(employees, d -> d.getName().equals("foo")) =>

            true
  

• max(employees, d -> d.getId()) =>

            30
  

• min(employees, d -> d.getId()) =>

            10
  

• sort([4,3,1,2], d -> d) =>

            [1,2,3,4]
  

• groupBy([1.2, 1.3, 2.1, 2.2, 3.1], d -> Math.floor(d)) =>

            [
                {1:[1.2,1.3]}
                {2:[2.1,2.2]}
                {3:[3.1]}
            ]
  

• indexBy(employees, Employee::getId =>

            [
                {10:fooEmployee}
                {20:barEmployee}
                {30:bazEmployee]}
            ]
  

• countBy([1, 2, 3, 4, 5, 6, 7], d -> d % 2 == 0 ? "even" : "odd" =>

            [
                {"even":3}
                {"odd":4}
            ]
  

• partition([1, 2, 3, 4, 5, 6, 7], d -> d % 2 == 0)

            {
                true:[2,4,6]
                false:[1,3,4,7]
            }
  

• flatten([[1, 2], [3, 4], [5, [6, 7]]])

            [1, 2, 3, 4, 5, 6, 7]
  

• without([1, 2, 3, 4, 5, 6, 7], 2,3)

            [1, 4, 5, 6, 7]
  

• chain([6,4,5,3,2,1]).filter(d -> d > 3).map(d -> d * d).filter(d -> d != 25).sort(d -> d).value();

            [16,36]
  

Version

1.0

Tech

All code in java and no external dependencies. Junit 4.10 will be required to run the tests

Installation

Should be available in maven central soon.

License

MIT

Contribution

Fork and send pull request

What's In the Name

If underscore is a small line, hyphen is even smaller. Compact readable code helps !!!