com.hp.hpl.jena.enhanced
Class Polymorphic<T>

java.lang.Object
  com.hp.hpl.jena.enhanced.Polymorphic<T>

Direct Known Subclasses:

EnhNode

public abstract class Polymorphic<T>
extends Object

Abstract base class for all polymorphic RDF objects, especially enhanced node and enhanced graph.

Author:

Jeremy Carroll (original code)
Chris Dollin (original code)
Ian Dickinson (tidying up and comments)

Method Summary

void	addView(Polymorphic<T> other) add another view for this object.
abstract boolean	equals(Object o) subclasses must override equals.
abstract boolean	isValid() answer true iff this enhanced node is still underpinned in the graph by triples appropriate to its type.
<X extends T> boolean	supports(Class<X> t) return _true_ iff this polymorphic object supports the specified interface.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

supports

public <X extends T> boolean supports(Class<X> t)

return _true_ iff this polymorphic object supports the specified interface. Synonymous with "does the argument class have this as an instance". Actually it shouldn't be. Review.

isValid

public abstract boolean isValid()

answer true iff this enhanced node is still underpinned in the graph by triples appropriate to its type.

equals

public abstract boolean equals(Object o)

subclasses must override equals. Actually they may not have to nowadays ... I have expunged the clever facet-identity test (and indeed facets).

Overrides:

equals in class Object

addView

public void addView(Polymorphic<T> other)

add another view for this object. other must be freshly constructed. To be called by subclasses when they have constructed a new view for this object.

The method is synchronised because addView is an update operation that may happen in a read context (because of .as()). Synchronising it ensures that simultaneous updates don't end up leaving the rings in an inconsistent state. (It's not clear whether this would actually lead to any problems; it's hard to write tests to expose these issues.) This method is public ONLY so that it can be tested. TODO find a better way to make it testable.