/**
* Copyright 2005-2014 Red Hat, Inc.
*
* Red Hat 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 io.fabric8.agent.sort;
import io.fabric8.agent.resolver.RequirementImpl;
import io.fabric8.agent.resolver.SimpleFilter;
import org.osgi.framework.Constants;
import org.osgi.resource.Capability;
import org.osgi.resource.Requirement;
import org.osgi.resource.Resource;
import java.util.Collection;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
public class RequirementSort {
/**
* Sorts {@link Resource} based on their {@link Requirement}s and {@link Capability}s.
* @param resources
* @return
*/
public Collection<Resource> sort(Collection<Resource> resources) {
Set<Resource> sorted = new LinkedHashSet<Resource>();
Set<Resource> visited = new LinkedHashSet<Resource>();
for (Resource r : resources) {
visit(r, resources, visited, sorted);
}
return sorted;
}
private void visit(Resource resource, Collection<Resource> resources, Set<Resource> visited, Set<Resource> sorted) {
if (visited.contains(resource)) {
return;
}
visited.add(resource);
for (Resource r : collectDependencies(resource, resources)) {
visit(r, resources, visited, sorted);
}
sorted.add(resource);
}
/**
* Finds the dependencies of the current resource.
* @param resource
* @param allResources
* @return
*/
private Set<Resource> collectDependencies(Resource resource, Collection<Resource> allResources) {
Set<Resource> result = new LinkedHashSet<Resource>();
List<Requirement> requirements = resource.getRequirements(null);
for (Requirement requirement : requirements) {
boolean isSatisfied = false;
for (Resource r : result) {
for (Capability capability : r.getCapabilities(null)) {
if (isSatisfied(requirement, capability)) {
isSatisfied = true;
break;
}
}
}
for (Resource r : allResources) {
if (!isSatisfied) {
for (Capability capability : r.getCapabilities(null)) {
if (isSatisfied(requirement, capability)) {
result.add(r);
break;
}
}
}
}
}
return result;
}
private boolean isSatisfied(Requirement requirement, Capability capability) {
RequirementImpl br;
if (requirement instanceof RequirementImpl) {
br = (RequirementImpl) requirement;
} else {
String filter = requirement.getDirectives().get(Constants.FILTER_DIRECTIVE);
SimpleFilter sf = (filter != null)
? SimpleFilter.parse(filter)
: new SimpleFilter(null, null, SimpleFilter.MATCH_ALL);
br = new RequirementImpl(null, requirement.getNamespace(), requirement.getDirectives(), requirement.getAttributes(), sf);
}
return br.matches(capability);
}
}