/*
* 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.tuscany.sca.builder.impl;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import org.apache.tuscany.sca.assembly.Component;
import org.apache.tuscany.sca.assembly.ComponentReference;
import org.apache.tuscany.sca.assembly.ComponentService;
import org.apache.tuscany.sca.assembly.Composite;
import org.apache.tuscany.sca.assembly.Endpoint;
import org.apache.tuscany.sca.assembly.EndpointReference;
import org.apache.tuscany.sca.assembly.Implementation;
import org.apache.tuscany.sca.assembly.builder.BuilderContext;
import org.apache.tuscany.sca.assembly.builder.CompositeBuilderException;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.policy.PolicySet;
import org.apache.tuscany.sca.policy.PolicySubject;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* A builder that checks that policy sets apply to the elements to which they are attached.
* Any that don't are removed. It first creates a DOM model for the composite so that the xpath
* expression can be evaluated. For each element that holds a policy set is calculates the
* appliesTo nodes and checks that the current element is in the set. If not the policySet is
* removed from the element
*
* @version $Rev: 996966 $ $Date: 2010-09-14 16:57:34 +0100 (Tue, 14 Sep 2010) $
*/
public class PolicyAppliesToBuilderImpl extends PolicyAttachmentBuilderImpl {
public PolicyAppliesToBuilderImpl(ExtensionPointRegistry registry) {
super(registry);
}
public String getID() {
return "org.apache.tuscany.sca.policy.builder.PolicyAppliesToBuilder";
}
public Composite build(Composite composite, BuilderContext context)
throws CompositeBuilderException {
try {
// create a DOM for the Domain Composite Infoset
Document document = saveAsDOM(composite);
// create a cache of evaluated node against each policy set so we don't
// have to keep evaluating policy sets that appear in multiple places
Map<PolicySet, List<PolicySubject>> appliesToSubjects = new HashMap<PolicySet, List<PolicySubject>>();
// for all implementations, endpoint and endpoint references check that
// the policy sets validly apply
return checkAppliesTo(document, appliesToSubjects, composite, context);
} catch (Exception e) {
throw new CompositeBuilderException(e);
}
}
private Composite checkAppliesTo(Document document, Map<PolicySet, List<PolicySubject>> appliesToSubjects, Composite topComposite, BuilderContext context) throws Exception {
for ( Component component : topComposite.getComponents() ) {
if ( component.getImplementation() instanceof Composite ) {
Composite nested = (Composite) component.getImplementation();
checkAppliesTo(saveAsDOM(nested),new HashMap<PolicySet, List<PolicySubject>>(), nested, context );
}
}
for (Component component : topComposite.getComponents()) {
for (ComponentService componentService : component.getServices()) {
for (Endpoint ep : componentService.getEndpoints()) {
List<PolicySet> policySetsToRemove = checkAppliesToSubject(document, appliesToSubjects, topComposite, (PolicySubject)ep.getService(), ep.getService().getPolicySets());
ep.getPolicySets().removeAll(policySetsToRemove);
if (ep.getBinding() instanceof PolicySubject) {
policySetsToRemove = checkAppliesToSubject(document, appliesToSubjects, topComposite, (PolicySubject)ep.getBinding(), ((PolicySubject)ep.getBinding()).getPolicySets());
ep.getPolicySets().removeAll(policySetsToRemove);
}
}
}
for (ComponentReference componentReference : component.getReferences()) {
for (EndpointReference epr : componentReference.getEndpointReferences()) {
List<PolicySet> policySetsToRemove = checkAppliesToSubject(document, appliesToSubjects, topComposite, (PolicySubject)epr.getReference(), epr.getReference().getPolicySets());
epr.getPolicySets().removeAll(policySetsToRemove);
if (epr.getBinding() instanceof PolicySubject) {
policySetsToRemove = checkAppliesToSubject(document, appliesToSubjects, topComposite, (PolicySubject)epr.getBinding(), ((PolicySubject)epr.getBinding()).getPolicySets());
epr.getPolicySets().removeAll(policySetsToRemove);
}
}
}
Implementation implementation = component.getImplementation();
if (implementation != null &&
implementation instanceof PolicySubject) {
checkAppliesToSubject(document, appliesToSubjects, topComposite, implementation, implementation.getPolicySets());
}
}
return topComposite;
}
/**
* Checks that all the provided policy sets apply to the provided policy subject
*
* @param document
* @param appliesToSubjects
* @param policySubject
* @param policySets
* @return
* @throws Exception
*/
private List<PolicySet> checkAppliesToSubject(Document document, Map<PolicySet, List<PolicySubject>> appliesToSubjects, Composite composite, PolicySubject policySubject, List<PolicySet> policySets) throws Exception {
List<PolicySet> policySetsToRemove = new ArrayList<PolicySet>();
for (PolicySet policySet : policySets){
List<PolicySubject> subjects = appliesToSubjects.get(policySet);
if (subjects == null){
XPathExpression appliesTo = policySet.getAppliesToXPathExpression();
if (appliesTo != null) {
NodeList nodes = (NodeList)appliesTo.evaluate(document, XPathConstants.NODESET);
if (nodes.getLength() > 0){
subjects = new ArrayList<PolicySubject>();
appliesToSubjects.put(policySet, subjects);
}
for (int i = 0; i < nodes.getLength(); i++) {
Node node = nodes.item(i);
String index = getStructuralURI(node);
PolicySubject subject = lookup(composite, index);
if ( subject != null )
subjects.add(subject);
}
}
}
if (subjects != null){
if (!subjects.contains(policySubject)){
policySetsToRemove.add(policySet);
}
}
// TODO - If no "appliesTo" is provided does the policy set apply to
// everything or nothing?
}
policySets.removeAll(policySetsToRemove);
return policySetsToRemove;
}
}