/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.jena.permissions.example;
import java.security.Principal ;
import java.util.Set ;
import org.apache.http.auth.BasicUserPrincipal ;
import org.apache.jena.graph.Node;
import org.apache.jena.graph.Triple;
import org.apache.jena.permissions.SecurityEvaluator ;
import org.apache.jena.rdf.model.* ;
import org.apache.jena.shared.AuthenticationRequiredException;
import org.apache.jena.vocabulary.RDF ;
/**
* An example evaluator that only provides access to messages in the graph that
* are from or to the principal.
*
*/
public class ExampleEvaluator implements SecurityEvaluator {
private Principal principal;
private Model model;
private RDFNode msgType = ResourceFactory.createResource( "http://example.com/msg" );
private Property pTo = ResourceFactory.createProperty( "http://example.com/to" );
private Property pFrom = ResourceFactory.createProperty( "http://example.com/from" );
/**
*
* @param model The graph we are going to evaluate against.
*/
public ExampleEvaluator( Model model )
{
this.model = model;
}
@Override
public boolean evaluate(Object principal, Action action, Node graphIRI) {
// we allow any action on a graph.
return true;
}
// not that in this implementation all permission checks flow through
// this method. We can do this because we have a simple permissions
// requirement. A more complex set of permissions requirement would
// require a different strategy.
private boolean evaluate( Object principalObj, Resource r )
{
Principal principal = (Principal)principalObj;
// we do not allow anonymous (un-authenticated) reads of data.
// Another strategy would be to only require authentication if the
// data being requested was restricted -- but that is a more complex
// process and not suitable for this simple example.
if (principal == null)
{
throw new AuthenticationRequiredException();
}
// a message is only available to sender or recipient
if (r.hasProperty( RDF.type, msgType ))
{
return r.hasProperty( pTo, principal.getName() ) ||
r.hasProperty( pFrom, principal.getName());
}
return true;
}
private boolean evaluate( Object principal, Node node )
{
if (node.equals( Node.ANY )) {
return false; // all wild cards are false
}
if (node.isURI() || node.isBlank()) {
Resource r = model.getRDFNode( node ).asResource();
return evaluate( principal, r );
}
return true;
}
private boolean evaluate( Object principal, Triple triple ) {
return evaluate( principal, triple.getSubject()) &&
evaluate( principal, triple.getObject()) &&
evaluate( principal, triple.getPredicate());
}
@Override
public boolean evaluate(Object principal, Action action, Node graphIRI, Triple triple) {
return evaluate( principal, triple );
}
@Override
public boolean evaluate(Object principal, Set<Action> actions, Node graphIRI) {
return true;
}
@Override
public boolean evaluate(Object principal, Set<Action> actions, Node graphIRI,
Triple triple) {
return evaluate( principal, triple );
}
@Override
public boolean evaluateAny(Object principal, Set<Action> actions, Node graphIRI) {
return true;
}
@Override
public boolean evaluateAny(Object principal, Set<Action> actions, Node graphIRI,
Triple triple) {
return evaluate( principal, triple );
}
@Override
public boolean evaluateUpdate(Object principal, Node graphIRI, Triple from, Triple to) {
return evaluate( principal, from ) && evaluate( principal, to );
}
public void setPrincipal( String userName )
{
if (userName == null)
{
principal = null;
}
principal = new BasicUserPrincipal( userName );
}
@Override
public Principal getPrincipal() {
return principal;
}
@Override
public boolean isPrincipalAuthenticated(Object principal) {
return principal != null;
}
}