akki777 / Opzio

Java's Optional functionality with optimisations for using chains.

Opzio

Java's Optional functionality with few modifications.

Advantages

• No get() method, so no chance of NullPointerException.
• Added ifAbsent() method, which can be used in conjunction with ifPresent() for Error Handling.

How-to-use

Basic usage

• orElse() method is kinda necessary to get non-null value.

String name = (String) Opzio.ofNullable(null).orElse("default");
System.out.println(name); // prints "default"

• Otherwise do,

Opzio<String> name = Opzio.ofNullable(null);
System.out.println(name); // prints "Opzio.empty"

Chaining

For hierarchy : apiResponse -> result -> data -> firstName,

• Do simply (using resolve method),

apiResponse.result.data.firstName = "Name";
Opzio.resolve(() -> apiResponse.result.data.firstName)
      .ifPresent(firstName -> System.out.println(firstName)) //prints "Name"
      .ifAbsent(() -> System.out.println("Error handling"));

• Or use map method,

apiResponse.result.data = null;
Opzio.ofNullable(apiResponse).map(v -> v.result).map(v -> v.data).map(v -> v.firstName)
     .ifPresent(firstName -> System.out.println(firstName))
     .ifAbsent(() -> System.out.println("Error handling")); // prints "Error handling"

Where-to-use

• Android projects, with minSdkversion < 24 and/or android-gradle-plugin version < 3.
  • Such projects can't use Java 8 features. But if using Retrolambda, can make use of Opzio.

Acknowledgements

• Benjamin [http://winterbe.com/posts/2015/03/15/avoid-null-checks-in-java/]
• Beildung [http://www.baeldung.com/java-optional]
• Oracle Java Optional class

Licence

Licensed under the MIT license.

Copyright (c) 2015 @akki777.