Usage example of Lazy.java written earlier

LazyUsage.java

package in.raam.lazy;

class IntensiveResource {
    public IntensiveResource() {
        // e.g.
        // obtain a JNDI object may be a datasource or remote objects
        // load values from file
        // create datasource manually
        // load a huge set of children objects for a parent collection
        System.out.println("Wait! performing CPU intensive operations...");
    }

    public static IntensiveResource buildResource() {
        System.out.println("Calling from method ref!");
        return new IntensiveResource();
    }

    public String doSomeOperation() {
        return "Some operation!";
    }
}

public class LazyUsage {

    public Lazy<IntensiveResource> r = Lazy.create(IntensiveResource.class, false);

    public Lazy<IntensiveResource> r1 = Lazy.create(IntensiveResource::buildResource);

    public Lazy<IntensiveResource> r2 = Lazy.create(() -> {
        System.out.println("Calling from lambda!");
        return new IntensiveResource();
    });

    public static void main(String[] args) {
        LazyUsage l = new LazyUsage();
        System.out.println("l.r.created :: " + l.r.created());
        System.out.println(l.r.value().doSomeOperation());
        System.out.println("l.r.created :: " + l.r.created());
        System.out.println(l.r.value() == null);
        System.out.println("l.r1.created :: " + l.r1.created());
        System.out.println(l.r1.value() == null);
        System.out.println("l.r1.created :: " + l.r1.created());
        System.out.println(l.r2.value().doSomeOperation());
        System.out.println(l.r2.value());
    }
}