java-bridge-extras-0.99: Utilities for working with the java-bridge package.

Portabilityportable (Haskell2010)
Safe HaskellNone



Every java methods returns in priniciple either Nothing or Just a value. This is quite cumbersome to work with. This module contains utility functions for working with Maybe values in the java monad.

This module offers the orphan instance (!)

 instance JavaObject a => JavaObject (Maybe a)

This instance allows you to apply toString and the like without unwrapping a Maybe value.

Note that the asObject function provided by this instance is undefined (since null is not an object). This is also the reason why this instance is not included in Foreign.Java by default. Invoking it will call error NullPointerException. In other words: This fine module will bring back all the joy of Java you might miss in Haskell :-)

toString will return null for Nothing.

hashCode will return 0 for Nothing.

classOf will return the class for java.lang.Void on Nothing, as this is a class for which there gare no object instances. This is only a stopgap and slightly incorrect, as null is not an object, and does therefor not have a class.