Add latency constraint
Change-Id: If9936e995e5a40370965b9693ff7dda941d8c5b8
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LatencyConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LatencyConstraint.java
new file mode 100644
index 0000000..ac9c5e2
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/LatencyConstraint.java
@@ -0,0 +1,95 @@
+/*
+ * 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.constraint;
+
+import com.google.common.base.MoreObjects;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.Path;
+import org.onlab.onos.net.intent.Constraint;
+import org.onlab.onos.net.resource.LinkResourceService;
+
+import java.time.Duration;
+import java.time.temporal.ChronoUnit;
+import java.util.Objects;
+
+/**
+ * Constraint that evaluates the latency through a path.
+ */
+public class LatencyConstraint implements Constraint {
+
+ // TODO: formalize the key for latency all over the codes.
+ private static final String LATENCY_KEY = "latency";
+
+ private final Duration latency;
+
+ /**
+ * Creates a new constraint to keep under specified latency through a path.
+ * @param latency latency to be kept
+ */
+ public LatencyConstraint(Duration latency) {
+ this.latency = latency;
+ }
+
+ public Duration getLatency() {
+ return latency;
+ }
+
+ @Override
+ public double cost(Link link, LinkResourceService resourceService) {
+ String value = link.annotations().value(LATENCY_KEY);
+
+ double latencyInMicroSec;
+ try {
+ latencyInMicroSec = Double.parseDouble(value);
+ } catch (NumberFormatException e) {
+ latencyInMicroSec = 1.0;
+ }
+
+ return latencyInMicroSec;
+ }
+
+ @Override
+ public boolean validate(Path path, LinkResourceService resourceService) {
+ double pathLatency = path.links().stream().mapToDouble(link -> cost(link, resourceService)).sum();
+ return Duration.of((long) pathLatency, ChronoUnit.MICROS).compareTo(latency) <= 0;
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(latency);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) {
+ return true;
+ }
+
+ if (!(obj instanceof LatencyConstraint)) {
+ return false;
+ }
+
+ final LatencyConstraint that = (LatencyConstraint) obj;
+ return Objects.equals(this.latency, that.latency);
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(this)
+ .add("latency", latency)
+ .toString();
+ }
+}