JarCastingtry-monad 
About
Inspired by scala.util.Try, this is small library that provides an abstraction of result of a function application.
Getting Started
<dependency> <groupId>com.jecklgamis</groupId> <artifactId>try-monad</artifactId> <version>1.0</version> </dependency>
compile 'com.jecklgamis:try-monad:1.0'
'com.jecklgamis:try-monad:jar:1.0'
@Grapes( @Grab(group='com.jecklgamis', module='try-monad', version='1.0') )
[com.jecklgamis/try-monad "1.0"]
A Primer On Using Try
Below is an example util function to check socket connection to a specified host.
import java.io.IOException;
import java.net.Socket;
import static com.jecklgamis.util.TryFactory.attempt;
public class ExampleUsage {
public static boolean canConnect(String host, int port) {
return attempt(() -> new Socket(host, port)).map((s) -> s.isConnected()).getOrElse(false);
}
public static void main(String[] args) {
System.out.println(canConnect("localhost", 80));
}
}
The canConnect function uses TryFactory.attempt (similar to try) to invoke a function that returns a socket instance (() → new Socket). It will then return an instance of Try , specifically a Success if there is no exception thrown, or Failure otherwise.
If the call is successful, the function passed to map (i.e. (s) → s.isConnected()) will be invoked. The s parameter in the expression is the result of function in attempt (a socket instance). If attempt fails (attempt returned a Failure), map will not be invoked and simply returns the Failure returned by attempt.
The last call in the chain is getOrElse(false), which will return a boolean depending on the output of map. If the map returns a Success (no exception thrown in (s)→ s.isConnected), `getOrElse will simply return the value of the function passed to map. Otherwise, getOrElse will return the given value, which in this case false.