Ghetto Type Aliases using Generic Bounds

ghettotypealiases.java

//
// the implementation for this class is in the package-private
// abstract class below. We are using type parameters to fake type aliases.
// Scroll down for details
//
public class DefinitionsBuildingContext
        extends DefinitionsContextHelper<
        /*EdgeT = */
        Edge<ViewConnector<BPMNViewDefinition>,
                Node<? extends View<? extends BPMNViewDefinition>, ?>>,

        /*NodeT = */
        Node<View<? extends BPMNViewDefinition>,
                Edge<ViewConnector<BPMNViewDefinition>,
                        Node<? extends View<? extends BPMNViewDefinition>, ?>>>
        > {

    public DefinitionsBuildingContext(
            Graph<DefinitionSet,
                    Node<View<? extends BPMNViewDefinition>,
                            Edge<ViewConnector<BPMNViewDefinition>,
                                    Node<? extends View<? extends BPMNViewDefinition>, ?>>>> graph) {
        super(graph);
    }

}

//
// this is sort-of a hack: we don't have type aliases in Java
// so we use this abstract class to bind a type-parameter to this horribly long
// Node, Edge declarations (because Node, Edge are... mutually recursive... erm)
// so we declare EdgeT, NodeT to "extend" the type we want to alias
// then in the concrete instance we actually **bind** them to the exact type
//
abstract class DefinitionsContextHelper<
        EdgeT extends
                Edge<ViewConnector<BPMNViewDefinition>,
                        Node<? extends View<? extends BPMNViewDefinition>, ?>>,
        NodeT extends
                Node<View<? extends BPMNViewDefinition>, EdgeT>
        > {

    private final Map<String, ? extends NodeT> nodes;

    private final Node firstNode;

    public DefinitionsContextHelper(Graph<DefinitionSet, NodeT> graph) {
    
    /* ... */
    
    }