/**
* 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.cxf.ws.policy;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import org.apache.cxf.helpers.CastUtils;
import org.apache.neethi.All;
import org.apache.neethi.Assertion;
import org.apache.neethi.ExactlyOne;
import org.apache.neethi.Policy;
/**
* This class contains methods dealing with policy intersection.
* Intersection of two assertions, i.e. computation if a compatible assertion,
* is domain specific and relies on AssertionBuilder.buildCompatible.
* See Section 4.5 in http://www.w3.org/TR/2006/WD-ws-policy-20061117.
*/
public class Intersector {
private AssertionBuilderRegistry assertionBuilderRegistry;
private boolean strict;
public Intersector(AssertionBuilderRegistry abr) {
assertionBuilderRegistry = abr;
strict = true;
}
public boolean isStrict() {
return strict;
}
public void setStrict(boolean s) {
strict = s;
}
boolean compatibleAssertions(Assertion a1, Assertion a2) {
AssertionBuilder ab = assertionBuilderRegistry.get(a1.getName());
if (null == ab) {
return false;
}
return null != ab.buildCompatible(a1, a2);
}
boolean compatibleAlternatives(Collection<Assertion> alt1, Collection<Assertion> alt2) {
if (alt1.isEmpty() || alt2.isEmpty()) {
return true;
}
if (strict) {
for (Assertion a1 : alt1) {
if (null == findCompatibleAssertion(a1, alt2)) {
return false;
}
}
for (Assertion a2 : alt2) {
if (null == findCompatibleAssertion(a2, alt1)) {
return false;
}
}
return true;
}
// Lax intersection not supported as neethi does not support Ignorable yet.
throw new UnsupportedOperationException("Lax intersection of assertions is not supported "
+ "because the Ignorable attribute is not supported.");
}
boolean compatiblePolicies(Policy p1, Policy p2) {
Iterator i1 = p1.getAlternatives();
while (i1.hasNext()) {
Collection<Assertion> alt1 = CastUtils.cast((Collection)i1.next(), Assertion.class);
Iterator i2 = p2.getAlternatives();
while (i2.hasNext()) {
Collection<Assertion> alt2 = CastUtils.cast((Collection)i2.next(), Assertion.class);
if (compatibleAlternatives(alt1, alt2)) {
return true;
}
}
return false;
}
return true;
}
public Assertion intersect(Assertion a1, Assertion a2) {
AssertionBuilder ab = assertionBuilderRegistry.get(a1.getName());
if (null == ab) {
return null;
}
return ab.buildCompatible(a1, a2);
}
public Collection<Assertion> intersect(Collection<Assertion> alt1,
Collection<Assertion> alt2) {
if (!compatibleAlternatives(alt1, alt2)) {
return null;
}
Collection<Assertion> intersection = new ArrayList<Assertion>();
intersection.addAll(alt1);
intersection.addAll(alt2);
return intersection;
}
public Policy intersect(Policy p1, Policy p2) {
if (!compatiblePolicies(p1, p2)) {
return null;
}
Policy compatible = new Policy();
ExactlyOne eo = new ExactlyOne();
Iterator i1 = p1.getAlternatives();
while (i1.hasNext()) {
List<Assertion> alt1 = CastUtils.cast((List)i1.next(), Assertion.class);
Iterator i2 = p2.getAlternatives();
while (i2.hasNext()) {
List<Assertion> alt2 = CastUtils.cast((List)i2.next(), Assertion.class);
if (compatibleAlternatives(alt1, alt2)) {
All all = new All();
all.addPolicyComponents(alt1);
all.addPolicyComponents(alt2);
eo.addPolicyComponent(all);
}
}
}
if (!eo.isEmpty()) {
compatible.addPolicyComponent(eo);
}
return compatible;
}
private Assertion findCompatibleAssertion(Assertion assertion, Collection<Assertion> alt) {
for (Assertion a : alt) {
Assertion compatible = intersect(assertion, a);
if (null != compatible) {
return compatible;
}
}
return null;
}
}