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/*
* (c) Copyright 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Hewlett-Packard Development Company, LP
* All rights reserved.
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* derived from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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*
* RDFNode.java
*
* Created on 25 July 2000, 13:13
*/
package com.hp.hpl.jena.rdf.model;
import com.hp.hpl.jena.graph.FrontsNode;
/**
Interface covering RDF resources and literals. Allows probing whether a
node is a literal/[blank, URI]resource, moving nodes from model to model,
and viewing them as different Java types using the .as() polymorphism.
@author bwm, kers
*/
public interface RDFNode extends FrontsNode
{
/**
Answer a String representation of the node. The form of the string
depends on the type of the node and is intended for human consumption,
not machine analysis.
*/
public String toString();
/**
Answer true iff this RDFNode is an anonynous resource. Useful for
one-off tests: see also visitWith() for making literal/anon/URI choices.
*/
public boolean isAnon();
/**
Answer true iff this RDFNode is a literal resource. Useful for
one-off tests: see also visitWith() for making literal/anon/URI choices.
*/
public boolean isLiteral();
/**
Answer true iff this RDFNode is an named resource. Useful for
one-off tests: see also visitWith() for making literal/anon/URI choices.
*/
public boolean isURIResource();
/**
Answer true iff this RDFNode is a URI resource or an anonynous
resource (ie is not a literal). Useful for one-off tests: see also
visitWith() for making literal/anon/URI choices.
*/
public boolean isResource();
/**
RDFNodes can be converted to different implementation types. Convert
this RDFNode to a type supporting the viewinterface. The
resulting RDFNode should be an instance of view and should
have any internal invariants as specified.
If the RDFNode has no Model attached, it can only be .as()ed to
a type it (this particular RDFNOde) already has.
If the RDFNode cannot be converted, an UnsupportedPolymorphism
exception is thrown..
*/
public T as( Class view );
/**
Answer true iff this RDFNode can be viewed as an instance of
view: that is, if it has already been viewed in this
way, or if it has an attached model in which it has properties that
permit it to be viewed in this way. If canAs returns
true, as on the same view should
deliver an instance of that class.
*/
public boolean canAs( Class view );
/**
Return the model associated with this resource. If the Resource
was not created by a Model, the result may be null.
@return The model associated with this resource.
*/
public Model getModel();
/**
Answer a .equals() version of this node, except that it's in the model
m.
@param m a model to move the node to
@return this, if it's already in m (or no model), a copy in m otherwise
*/
public RDFNode inModel( Model m );
/**
Apply the appropriate method of the visitor to this node's content and
return the result.
@param rv an RDFVisitor with a method for URI/blank/literal nodes
@return the result returned by the selected method
*/
public Object visitWith( RDFVisitor rv );
/**
If this node is a Resource, answer that resource; otherwise throw an
exception.
*/
public Resource asResource();
/**
If this node is a Literal, answer that literal; otherwise throw an
exception.
*/
public Literal asLiteral();
}