Second usage example for Lazy type.

LazyUsage2.java

package in.raam.lazy;

import java.util.ArrayList;
import java.util.List;

class Parent {

    private String key;
    private Lazy<List<Child>> children = Lazy.create(() -> new ParentHelper().loadChildren(this));
    public Lazy<List<AnotherChild>> childList = Lazy.create(this::loadChildList);

    public Parent(String key) {
        this.key = key;
    }

    public String getKey() {
        return key;
    }

    public List<Child> getChildren() {
        System.out.println("children.created :: " + children.created());
        return children.value();
    }

    private List<AnotherChild> loadChildList() {
        System.out.println("Loading all another child list!!!");
        // fetch 1000s of records from DB OR fetch from a Webservice etc.
        return new ArrayList<>();
    }
}

class Child {
    // numerous attributes
}

class AnotherChild {
    // numerous attributes
}

class ParentHelper {

    public List<Child> loadChildren(Parent parent) {
        System.out.println("Loading all children!!!");
        // fetch 1000s of records from DB OR fetch from a Webservice etc.
        return new ArrayList<>();
    }

}

public class LazyUsage2 {
    public static void main(String[] args) {
        Parent p = new Parent("KEY");
        System.out.println(p.getKey());
        System.out.println(p.getChildren().size());
        System.out.println(p.getChildren().isEmpty());
        System.out.println(p.getChildren());
        System.out.println("p.childList.created() :: " + p.childList.created());
        System.out.println(p.childList.value().size());
        System.out.println("p.childList.created() :: " + p.childList.created());
        System.out.println(p.childList.value().isEmpty());
        System.out.println(p.childList.value());
    }
}