Add constraint for link annotated value

Change-Id: Ia51e488de1ae885da02493f09156afbd52c53592

+/*
+ * 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();
+    }
+}

+/*
+ * 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.testing.EqualsTester;
+import org.junit.Before;
+import org.junit.Test;
+import org.onlab.onos.net.DefaultAnnotations;
+import org.onlab.onos.net.DefaultLink;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.net.Link;
+import org.onlab.onos.net.PortNumber;
+import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.net.resource.LinkResourceService;
+
+import static org.easymock.EasyMock.createMock;
+import static org.hamcrest.Matchers.closeTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.lessThan;
+import static org.junit.Assert.assertThat;
+import static org.onlab.onos.net.DefaultLinkTest.cp;
+import static org.onlab.onos.net.DeviceId.deviceId;
+import static org.onlab.onos.net.Link.Type.DIRECT;
+import static org.onlab.onos.net.PortNumber.portNumber;
+
+/**
+ * Test for link annotated value threshold.
+ */
+public class AnnotationConstraintTest {
+
+    private static final ProviderId PID = new ProviderId("of", "foo");
+    private static final DeviceId DID1 = deviceId("of:1");
+    private static final DeviceId DID2 = deviceId("of:2");
+    private static final PortNumber PID1 = portNumber(1);
+    private static final PortNumber PID2 = portNumber(2);
+    private static final String KEY = "distance";
+    private static final double VALUE = 100;
+
+    private AnnotationConstraint sut;
+    private Link link;
+    private LinkResourceService linkResourceService;
+
+    @Before
+    public void setUp() {
+        linkResourceService = createMock(LinkResourceService.class);
+
+        DefaultAnnotations annotations = DefaultAnnotations.builder().set(KEY, String.valueOf(VALUE)).build();
+
+        link = new DefaultLink(PID, cp(DID1, PID1), cp(DID2, PID2), DIRECT, annotations);
+    }
+
+    /**
+     * Tests the specified annotated value is less than the threshold.
+     */
+    @Test
+    public void testLessThanThreshold() {
+        double value = 120;
+        sut = new AnnotationConstraint(KEY, value);
+
+        assertThat(sut.isValid(link, linkResourceService), is(true));
+        assertThat(sut.cost(link, linkResourceService), is(closeTo(VALUE, 1.0e-6)));
+    }
+
+    /**
+     * Tests the specified annotated value is more than the threshold.
+     */
+    @Test
+    public void testMoreThanThreshold() {
+        double value = 80;
+        sut = new AnnotationConstraint(KEY, value);
+
+        assertThat(sut.isValid(link, linkResourceService), is(false));
+        assertThat(sut.cost(link, linkResourceService), is(lessThan(0.0)));
+    }
+
+    @Test
+    public void testEquality() {
+        new EqualsTester()
+                .addEqualityGroup(new AnnotationConstraint(KEY, 100), new AnnotationConstraint(KEY, 100))
+                .addEqualityGroup(new AnnotationConstraint(KEY, 120))
+                .addEqualityGroup(new AnnotationConstraint("latency", 100))
+                .testEquals();
+    }
+}