adding constaints to intent API
diff --git a/core/net/src/main/java/org/onlab/onos/net/intent/impl/ConnectivityIntentCompiler.java b/core/net/src/main/java/org/onlab/onos/net/intent/impl/ConnectivityIntentCompiler.java
new file mode 100644
index 0000000..cecff78
--- /dev/null
+++ b/core/net/src/main/java/org/onlab/onos/net/intent/impl/ConnectivityIntentCompiler.java
@@ -0,0 +1,136 @@
+/*
+ * Copyright 2014 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.onlab.onos.net.intent.impl;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.onlab.onos.net.ElementId;
+import org.onlab.onos.net.Path;
+import org.onlab.onos.net.intent.ConnectivityIntent;
+import org.onlab.onos.net.intent.Constraint;
+import org.onlab.onos.net.intent.IntentCompiler;
+import org.onlab.onos.net.intent.IntentExtensionService;
+import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.net.resource.LinkResourceService;
+import org.onlab.onos.net.topology.LinkWeight;
+import org.onlab.onos.net.topology.PathService;
+import org.onlab.onos.net.topology.TopologyEdge;
+
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+
+/**
+ * Base class for compilers of various
+ * {@link org.onlab.onos.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.onlab.onos.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
+ * @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 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()));
+ if (paths.isEmpty()) {
+ throw new PathNotFoundException("No packet path from " + one + " to " + two);
+ }
+ // TODO: let's be more intelligent about this eventually
+ return paths.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) {
+ this.constraints = constraints;
+ }
+
+ @Override
+ public double weight(TopologyEdge edge) {
+ if (constraints == null) {
+ 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;
+ }
+ }
+
+}