Manifold

Who is using Manifold?

Sampling of companies using Manifold:

What can you do with Manifold?

Extension Methods

Add your own methods to existing Java classes, even String, List, and File. Eliminate boilerplate code.  ▶ Check it out!

String greeting = "hello";
greeting.myMethod(); // Add your own methods to String!

Delegation

Favor composition over inheritance. Use @link and @part for automatic interface implementation forwarding and true delegation.

> class MyClass implements MyInterface {
>   @link MyInterface myInterface; // transfers calls on MyInterface to myInterface
>
>   public MyClass(MyInterface myInterface) {
>     this.myInterface = myInterface; // dynamically configure behavior
>   }
>
>   // No need to implement MyInterface here, but you can override myInterface as needed
> }
> ```

### [Properties](https://github.com/manifold-systems/manifold/tree/master/manifold-deps-parent/manifold-props)
Eliminate boilerplate getter/setter code, improve your overall dev experience with properties.
```java
public interface Book {
  @var String title; // no more boilerplate code!
}
// refer to it directly by name
book.title = "Daisy";     // calls setter
String name = book.title; // calls getter 
book.title += " chain";   // calls getter & setter

Additionally, the feature automatically infers properties, both from your existing source files and from compiled classes your project uses. Reduce property use from this:

Actor person = result.getMovie().getLeadingRole().getActor();
Likes likes = person.getLikes();
likes.setCount(likes.getCount() + 1);

to this:

result.movie.leadingRole.actor.likes.count++;

Tuple expressions

Tuple expressions provide concise syntax to group named data items in a lightweight structure.

var t = (name: "Bob", age: "35");
System.out.println("Name: " + t.name + " Age: " + t.age);

var t = (person.name, person.age);
System.out.println("Name: " + t.name + " Age: " + t.age);

You can also use tuples with new auto type inference to enable multiple return values from a method.

Unit Expressions

Unit or binding operations are unique to the Manifold framework. They provide a powerfully concise syntax and can be applied to a wide range of applications.

import static manifold.science.util.UnitConstants.*; // kg, m, s, ft, etc
...
Length distance = 100 mph * 3 hr;
Force f = 5.2 kg m/s/s; // same as 5.2 N
Mass infant = 9 lb + 8.71 oz;

Ranges

Easily work with the Range API using unit expressions. Simply import the RangeFun constants to create ranges.

// imports the `to`, `step`, and other "binding" constants
import static manifold.collections.api.range.RangeFun.*;
...
for (int i: 1 to 5) {
  out.println(i);
}

for (Mass m: 0kg to 10kg step 22r unit g) {
  out.println(m);
}

Science

Use the manifold-science framework to type-safely incorporate units and precise measurements into your applications.

import static manifold.science.util.UnitConstants.*; // kg, m, s, ft, etc.
...
Velocity rate = 65mph;
Time time = 1min + 3.7sec;
Length distance = rate * time;

#if JAVA_8_OR_LATER @Override public void setTime(LocalDateTime time) {…} #else @Override public void setTime(Calendar time) {…} #endif

### [Structural Typing](https://github.com/manifold-systems/manifold/tree/master/manifold-deps-parent/manifold-ext#structural-interfaces-via-structural)
Unify disparate APIs. Bridge software components you do not control. Access maps through type-safe interfaces. [ **▶** Check it out!](http://manifold.systems/images/structural%20typing.mp4)
```java
Map<String, Object> map = new HashMap<>();
MyThingInterface thing = (MyThingInterface) map; // O_o
thing.setFoo(new Foo());
Foo foo = thing.getFoo();
out.println(thing.getClass()); // prints "java.util.HashMap"

Type-safe Reflection

Access private features with @Jailbreak to avoid the drudgery and vulnerability of Java reflection.  ▶ Check it out!

@Jailbreak Foo foo = new Foo();
// Direct, *type-safe* access to *all* foo's members
foo.privateMethod(x, y, z);
foo.privateField = value;

Checked Exception Handling

You now have an option to make checked exceptions behave like unchecked exceptions! No more unintended exception swallowing. No more try/catch/wrap/rethrow boilerplate!

List<String> strings = ...;
List<URL> urls = strings.stream()
  .map(URL::new) // No need to handle the MalformedURLException!
  .collect(Collectors.toList());

String Templates

Inline variables and expressions in String literals, no more clunky string concat!  ▶ Check it out!

int hour = 15;
// Simple variable access with '$'
String result = "The hour is $hour"; // Yes!!!
// Use expressions with '${}'
result = "It is ${hour > 12 ? hour-12 : hour} o'clock";

Projects

The Manifold project consists of the core Manifold framework and a collection of sub-projects implementing SPIs provided by the core framework. Each project consists of one or more dependencies you can easily add to your project:

Manifold : Core

Manifold : Extensions

Manifold : Delegation

Manifold : Properties

Manifold : Tuples

Manifold : SQL
Manifold : GraphQL
Manifold : JSON
Manifold : XML
Manifold : YAML
Manifold : CSV
Manifold : Property Files
Manifold : Image
Manifold : Dark Java
Manifold : JavaScript

Manifold : Java Templates

Manifold : String Interpolation
Manifold : (Un)checked Exceptions

Manifold : Preprocessor

Manifold : Science

Manifold : Collections
Manifold : I/0
Manifold : Text

Experiment with sample projects:

• Manifold : Sample App
  
• Manifold : Sample SQL App
  
• Manifold : Sample GraphQL App
  
• Manifold : Sample REST API App
  
• Manifold : Sample Web App
• Manifold : Gradle Example Project
• Manifold : Sample Kotlin App

Chat

Join our Slack Group to start a discussion, ask questions, provide feedback, etc. Someone is usually there to help.