Add constraint for link annotated value
Change-Id: Ia51e488de1ae885da02493f09156afbd52c53592
diff --git a/core/api/src/main/java/org/onlab/onos/net/intent/constraint/AnnotationConstraint.java b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/AnnotationConstraint.java
new file mode 100644
index 0000000..ac76303
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/net/intent/constraint/AnnotationConstraint.java
@@ -0,0 +1,122 @@
+/*
+ * 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.resource.LinkResourceService;
+
+import java.util.Objects;
+
+/**
+ * Constraint that evaluates an arbitrary link annotated value is under the specified threshold.
+ */
+public class AnnotationConstraint extends BooleanConstraint {
+
+ private final String key;
+ private final double threshold;
+
+ /**
+ * Creates a new constraint to keep the value for the specified key
+ * of link annotation under the threshold.
+ *
+ * @param key key of link annotation
+ * @param threshold threshold value of the specified link annotation
+ */
+ public AnnotationConstraint(String key, double threshold) {
+ this.key = key;
+ this.threshold = threshold;
+ }
+
+ /**
+ * Returns the key of link annotation this constraint designates.
+ * @return key of link annotation
+ */
+ public String key() {
+ return key;
+ }
+
+ /**
+ * Returns the threshold this constraint ensures as link annotated value.
+ *
+ * @return threshold as link annotated value
+ */
+ public double threshold() {
+ return threshold;
+ }
+
+ @Override
+ public boolean isValid(Link link, LinkResourceService resourceService) {
+ double value = getAnnotatedValue(link, key);
+
+ return value <= threshold;
+ }
+
+ /**
+ * Returns the annotated value of the specified link. The annotated value
+ * is expected to be String that can be parsed as double. If parsing fails,
+ * the returned value will be 1.0.
+ *
+ * @param link link whose annotated value is obtained
+ * @param key key of link annotation
+ * @return double value of link annotation for the specified key
+ */
+ private double getAnnotatedValue(Link link, String key) {
+ double value;
+ try {
+ value = Double.parseDouble(link.annotations().value(key));
+ } catch (NumberFormatException e) {
+ value = 1.0;
+ }
+ return value;
+ }
+
+ @Override
+ public double cost(Link link, LinkResourceService resourceService) {
+ if (isValid(link, resourceService)) {
+ return getAnnotatedValue(link, key);
+ } else {
+ return -1;
+ }
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(key, threshold);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (this == obj) {
+ return true;
+ }
+
+ if (!(obj instanceof AnnotationConstraint)) {
+ return false;
+ }
+
+ final AnnotationConstraint other = (AnnotationConstraint) obj;
+ return Objects.equals(this.key, other.key) && Objects.equals(this.threshold, other.threshold);
+ }
+
+ @Override
+ public String toString() {
+ return MoreObjects.toStringHelper(this)
+ .add("key", key)
+ .add("threshold", threshold)
+ .toString();
+ }
+}