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/*
* Copyright 2014-2015 Open Networking Laboratory
*
* Licensed 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.onosproject.net.intent.impl.compiler;
import com.google.common.collect.FluentIterable;
import com.google.common.collect.ImmutableList;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.Reference;
import org.apache.felix.scr.annotations.ReferenceCardinality;
import org.onosproject.net.ElementId;
import org.onosproject.net.Path;
import org.onosproject.net.intent.ConnectivityIntent;
import org.onosproject.net.intent.Constraint;
import org.onosproject.net.intent.IntentCompiler;
import org.onosproject.net.intent.IntentExtensionService;
import org.onosproject.net.intent.impl.PathNotFoundException;
import org.onosproject.net.provider.ProviderId;
import org.onosproject.net.resource.link.LinkResourceService;
import org.onosproject.net.topology.LinkWeight;
import org.onosproject.net.topology.PathService;
import org.onosproject.net.topology.TopologyEdge;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
/**
* Base class for compilers of various
* {@link org.onosproject.net.intent.ConnectivityIntent connectivity intents}.
*/
@Component(immediate = true)
public abstract class ConnectivityIntentCompiler<T extends ConnectivityIntent>
implements IntentCompiler<T> {
private static final ProviderId PID = new ProviderId("core", "org.onosproject.core", true);
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected IntentExtensionService intentManager;
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected PathService pathService;
@Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
protected LinkResourceService resourceService;
/**
* Returns an edge-weight capable of evaluating links on the basis of the
* specified constraints.
*
* @param constraints path constraints
* @return edge-weight function
*/
protected LinkWeight weight(List<Constraint> constraints) {
return new ConstraintBasedLinkWeight(constraints);
}
/**
* Validates the specified path against the given constraints.
*
* @param path path to be checked
* @param constraints path constraints
* @return true if the path passes all constraints
*/
protected boolean checkPath(Path path, List<Constraint> constraints) {
for (Constraint constraint : constraints) {
if (!constraint.validate(path, resourceService)) {
return false;
}
}
return true;
}
/**
* Computes a path between two ConnectPoints.
*
* @param intent intent on which behalf path is being computed
* @param one start of the path
* @param two end of the path
* @return Path between the two
* @throws PathNotFoundException if a path cannot be found
*/
protected Path getPath(ConnectivityIntent intent,
ElementId one, ElementId two) {
Set<Path> paths = pathService.getPaths(one, two, weight(intent.constraints()));
final List<Constraint> constraints = intent.constraints();
ImmutableList<Path> filtered = FluentIterable.from(paths)
.filter(path -> checkPath(path, constraints))
.toList();
if (filtered.isEmpty()) {
throw new PathNotFoundException(one, two);
}
// TODO: let's be more intelligent about this eventually
return filtered.iterator().next();
}
/**
* Edge-weight capable of evaluating link cost using a set of constraints.
*/
protected class ConstraintBasedLinkWeight implements LinkWeight {
private final List<Constraint> constraints;
/**
* Creates a new edge-weight function capable of evaluating links
* on the basis of the specified constraints.
*
* @param constraints path constraints
*/
ConstraintBasedLinkWeight(List<Constraint> constraints) {
if (constraints == null) {
this.constraints = Collections.emptyList();
} else {
this.constraints = ImmutableList.copyOf(constraints);
}
}
@Override
public double weight(TopologyEdge edge) {
if (!constraints.iterator().hasNext()) {
return 1.0;
}
// iterate over all constraints in order and return the weight of
// the first one with fast fail over the first failure
Iterator<Constraint> it = constraints.iterator();
double cost = it.next().cost(edge.link(), resourceService);
while (it.hasNext() && cost > 0) {
if (it.next().cost(edge.link(), resourceService) < 0) {
return -1;
}
}
return cost;
}
}
}
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