Add sub-types to distinguish type of resources

Change-Id: Ia43cbf4a13937c9bd9dbc97221062ef5fa3e578f

@@ -19,13 +19,14 @@ import com.google.common.annotations.Beta;
 import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 
-import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 
+import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 
 /**
  * An object that is used to locate a resource in a network.
@@ -33,25 +34,45 @@ import static com.google.common.base.Preconditions.checkNotNull;
  * of elementary resources that are not globally identifiable. A ResourcePath can be a globally
  * unique resource identifier.
  *
+ * Two types of resource are considered. One is discrete type and the other is continuous type.
+ * Discrete type resource is a resource whose amount is measured as a discrete unit. VLAN ID and
+ * MPLS label are examples of discrete type resource. Continuous type resource is a resource whose
+ * amount is measured as a continuous value. Bandwidth is an example of continuous type resource.
+ * A double value is associated with a continuous type value.
+ *
  * Users of this class must keep the semantics of resources regarding the hierarchical structure.
  * For example, resource path, Link:1/VLAN ID:100, is valid, but resource path, VLAN ID:100/Link:1
  * is not valid because a link is not a sub-component of a VLAN ID.
  */
 @Beta
-public final class ResourcePath {
+public abstract class ResourcePath {
 
-    private final ResourcePath parent;
+    private final Discrete parent;
     private final Object last;
 
-    public static final ResourcePath ROOT = new ResourcePath(ImmutableList.of());
+    public static final Discrete ROOT = new Discrete();
 
     /**
-     * Creates an resource path from the specified components.
+     * Creates an resource path which represents a discrete-type resource from the specified components.
+     *
+     * @param components components of the path. The order represents hierarchical structure of the resource.
+     */
+    public static ResourcePath discrete(Object... components) {
+        if (components.length == 0) {
+            return ROOT;
+        } else {
+            return new Discrete(ImmutableList.copyOf(components));
+        }
+    }
+
+    /**
+     * Creates an resource path which represents a continuous-type resource from the specified components.
      *
+     * @param value amount of the resource
      * @param components components of the path. The order represents hierarchical structure of the resource.
      */
-    public ResourcePath(Object... components) {
-        this(Arrays.asList(components));
+    public static ResourcePath continuous(double value, Object... components) {
+        return new Continuous(ImmutableList.copyOf(components), value);
     }
 
     /**
@@ -59,17 +80,17 @@ public final class ResourcePath {
      *
      * @param components components of the path. The order represents hierarchical structure of the resource.
      */
-    public ResourcePath(List<Object> components) {
+    ResourcePath(List<Object> components) {
         checkNotNull(components);
-        if (components.isEmpty()) {
-            this.parent = null;
-            this.last = null;
-            return;
-        }
+        checkArgument(!components.isEmpty());
 
         LinkedList<Object> children = new LinkedList<>(components);
         this.last = children.pollLast();
-        this.parent = new ResourcePath(children);
+        if (children.isEmpty()) {
+            this.parent = ROOT;
+        } else {
+            this.parent = new Discrete(children);
+        }
     }
 
     /**
@@ -78,9 +99,12 @@ public final class ResourcePath {
      * @param parent the parent of this resource
      * @param last a child of the parent
      */
-    public ResourcePath(ResourcePath parent, Object last) {
-        this.parent = checkNotNull(parent);
-        this.last = checkNotNull(last);
+    ResourcePath(Discrete parent, Object last) {
+        checkNotNull(parent);
+        checkNotNull(last);
+
+        this.parent = parent;
+        this.last = last;
     }
 
     // for serialization
@@ -97,10 +121,10 @@ public final class ResourcePath {
     public List<Object> components() {
         LinkedList<Object> components = new LinkedList<>();
 
-        ResourcePath parentPath = parent;
-        while (parentPath != null) {
+        Optional<Discrete> parentPath = Optional.ofNullable(parent);
+        while (parentPath.isPresent()) {
             components.addFirst(last);
-            parentPath = parent.parent;
+            parentPath = parent.parent();
         }
 
         return components;
@@ -113,12 +137,20 @@ public final class ResourcePath {
      * @return the parent resource path of this instance.
      * If there is no parent, empty instance will be returned.
      */
-    public Optional<ResourcePath> parent() {
+    public Optional<Discrete> parent() {
         return Optional.ofNullable(parent);
     }
 
     public ResourcePath child(Object child) {
-        return new ResourcePath(this, child);
+        checkState(this instanceof Discrete);
+
+        return new Discrete((Discrete) this, child);
+    }
+
+    public ResourcePath child(Object child, double value) {
+        checkState(this instanceof Discrete);
+
+        return new Continuous((Discrete) this, child, value);
     }
 
     /**
@@ -156,4 +188,57 @@ public final class ResourcePath {
                 .add("last", last)
                 .toString();
     }
+
+    /**
+     * Represents a resource path which specifies a resource which can be measured
+     * as a discrete unit. A VLAN ID and a MPLS label of a link are examples of the resource.
+     * <p>
+     * Note: This class is exposed to the public, but intended to be used in the resource API
+     * implementation only. It is not for resource API user.
+     * </p>
+     */
+    public static final class Discrete extends ResourcePath {
+        private Discrete() {
+            super();
+        }
+
+        private Discrete(List<Object> components) {
+            super(components);
+        }
+
+        private Discrete(Discrete parent, Object last) {
+            super(parent, last);
+        }
+    }
+
+    /**
+     * Represents a resource path which specifies a resource which can be measured
+     * as continuous value. Bandwidth of a link is an example of the resource.
+     * <p>
+     * Note: This class is exposed to the public, but intended to be used in the resource API
+     * implementation only. It is not for resource API user.
+     */
+    public static final class Continuous extends ResourcePath {
+        // Note: value is not taken into account for equality
+        private final double value;
+
+        private Continuous(List<Object> components, double value) {
+            super(components);
+            this.value = value;
+        }
+
+        public Continuous(Discrete parent, Object last, double value) {
+            super(parent, last);
+            this.value = value;
+        }
+
+        /**
+         * Returns the value of the resource amount.
+         *
+         * @return the value of the resource amount
+         */
+        public double value() {
+            return value;
+        }
+    }
 }

@@ -38,9 +38,9 @@ public class ResourceAllocationTest {
 
     @Test
     public void testEquals() {
-        ResourceAllocation alloc1 = new ResourceAllocation(new ResourcePath(LK1, VLAN1), IID1);
-        ResourceAllocation sameAsAlloc1 = new ResourceAllocation(new ResourcePath(LK1, VLAN1), IID1);
-        ResourceAllocation alloc2 = new ResourceAllocation(new ResourcePath(LK2, VLAN1), IID1);
+        ResourceAllocation alloc1 = new ResourceAllocation(ResourcePath.discrete(LK1, VLAN1), IID1);
+        ResourceAllocation sameAsAlloc1 = new ResourceAllocation(ResourcePath.discrete(LK1, VLAN1), IID1);
+        ResourceAllocation alloc2 = new ResourceAllocation(ResourcePath.discrete(LK2, VLAN1), IID1);
 
         new EqualsTester()
                 .addEqualityGroup(alloc1, sameAsAlloc1)

@@ -18,6 +18,7 @@ package org.onosproject.net.newresource;
 import com.google.common.testing.EqualsTester;
 import org.junit.Test;
 import org.onlab.packet.VlanId;
+import org.onlab.util.Bandwidth;
 import org.onosproject.net.ConnectPoint;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.LinkKey;
@@ -36,37 +37,42 @@ public class ResourcePathTest {
     private static final ConnectPoint CP1_1 = new ConnectPoint(D1, P1);
     private static final ConnectPoint CP2_1 = new ConnectPoint(D2, P1);
     private static final VlanId VLAN1 = VlanId.vlanId((short) 100);
+    private static final Bandwidth BW1 = Bandwidth.gbps(2);
+    private static final Bandwidth BW2 = Bandwidth.gbps(1);
 
     @Test
     public void testEquals() {
-        ResourcePath resource1 = new ResourcePath(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
-        ResourcePath sameAsResource1 = new ResourcePath(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
-        ResourcePath resource2 = new ResourcePath(LinkKey.linkKey(CP2_1, CP1_1), VLAN1);
+        ResourcePath resource1 = ResourcePath.discrete(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
+        ResourcePath sameAsResource1 = ResourcePath.discrete(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
+        ResourcePath resource2 = ResourcePath.discrete(LinkKey.linkKey(CP2_1, CP1_1), VLAN1);
+        ResourcePath resource3 = ResourcePath.continuous(BW1.bps(), LinkKey.linkKey(CP1_1, CP2_1), BW1);
+        ResourcePath sameAsResource3 = ResourcePath.continuous(BW2.bps(), LinkKey.linkKey(CP1_1, CP2_1), BW1);
 
         new EqualsTester()
                 .addEqualityGroup(resource1, sameAsResource1)
                 .addEqualityGroup(resource2)
+                .addEqualityGroup(resource3, sameAsResource3)   // this is intentional
                 .testEquals();
     }
 
     @Test
     public void testCreateWithZeroComponent() {
-        ResourcePath path = new ResourcePath();
+        ResourcePath path = ResourcePath.discrete();
 
         assertThat(path, is(ResourcePath.ROOT));
     }
 
     @Test
     public void testThereIsParent() {
-        ResourcePath path = new ResourcePath(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
-        ResourcePath parent = new ResourcePath(LinkKey.linkKey(CP1_1, CP2_1));
+        ResourcePath path = ResourcePath.discrete(LinkKey.linkKey(CP1_1, CP2_1), VLAN1);
+        ResourcePath parent = ResourcePath.discrete(LinkKey.linkKey(CP1_1, CP2_1));
 
         assertThat(path.parent(), is(Optional.of(parent)));
     }
 
     @Test
     public void testNoParent() {
-        ResourcePath path = new ResourcePath(LinkKey.linkKey(CP1_1, CP2_1));
+        ResourcePath path = ResourcePath.discrete(LinkKey.linkKey(CP1_1, CP2_1));
 
         assertThat(path.parent(), is(Optional.of(ResourcePath.ROOT)));
     }
@@ -74,7 +80,7 @@ public class ResourcePathTest {
     @Test
     public void testBase() {
         LinkKey linkKey = LinkKey.linkKey(CP1_1, CP2_1);
-        ResourcePath path = new ResourcePath(linkKey);
+        ResourcePath path = ResourcePath.discrete(linkKey);
 
         LinkKey child = (LinkKey) path.last();
         assertThat(child, is(linkKey));

@@ -121,7 +121,7 @@ public class MplsPathIntentCompiler implements IntentCompiler<MplsPathIntent> {
         }
 
         List<ResourcePath> resources = labels.entrySet().stream()
-                .map(x -> new ResourcePath(linkKey(x.getKey().src(), x.getKey().src()), x.getValue()))
+                .map(x -> ResourcePath.discrete(linkKey(x.getKey().src(), x.getKey().src()), x.getValue()))
                 .collect(Collectors.toList());
         List<org.onosproject.net.newresource.ResourceAllocation> allocations =
                 resourceService.allocate(intent.id(), resources);
@@ -145,7 +145,7 @@ public class MplsPathIntentCompiler implements IntentCompiler<MplsPathIntent> {
     }
 
     private Optional<MplsLabel> findMplsLabel(LinkKey link) {
-        return resourceService.getAvailableResources(new ResourcePath(link)).stream()
+        return resourceService.getAvailableResources(ResourcePath.discrete(link)).stream()
                 .filter(x -> x.last() instanceof MplsLabel)
                 .map(x -> (MplsLabel) x.last())
                 .findFirst();

@@ -160,8 +160,8 @@ public class OpticalCircuitIntentCompiler implements IntentCompiler<OpticalCircu
         log.debug("Compiling optical circuit intent between {} and {}", src, dst);
 
         // Reserve OduClt ports
-        ResourcePath srcPortPath = new ResourcePath(src.deviceId(), src.port());
-        ResourcePath dstPortPath = new ResourcePath(dst.deviceId(), dst.port());
+        ResourcePath srcPortPath = ResourcePath.discrete(src.deviceId(), src.port());
+        ResourcePath dstPortPath = ResourcePath.discrete(dst.deviceId(), dst.port());
         List<ResourceAllocation> allocation = resourceService.allocate(intent.id(), srcPortPath, dstPortPath);
         if (allocation.isEmpty()) {
             throw new IntentCompilationException("Unable to reserve ports for intent " + intent);
@@ -312,7 +312,7 @@ public class OpticalCircuitIntentCompiler implements IntentCompiler<OpticalCircu
         if (ochCP != null) {
             OchPort ochPort = (OchPort) deviceService.getPort(ochCP.deviceId(), ochCP.port());
             Optional<IntentId> intentId =
-                    resourceService.getResourceAllocation(new ResourcePath(ochCP.deviceId(), ochCP.port()))
+                    resourceService.getResourceAllocation(ResourcePath.discrete(ochCP.deviceId(), ochCP.port()))
                             .map(ResourceAllocation::consumer)
                             .filter(x -> x instanceof IntentId)
                             .map(x -> (IntentId) x);
@@ -331,7 +331,7 @@ public class OpticalCircuitIntentCompiler implements IntentCompiler<OpticalCircu
             }
 
             Optional<IntentId> intentId =
-                    resourceService.getResourceAllocation(new ResourcePath(oduPort.deviceId(), port.number()))
+                    resourceService.getResourceAllocation(ResourcePath.discrete(oduPort.deviceId(), port.number()))
                             .map(ResourceAllocation::consumer)
                             .filter(x -> x instanceof IntentId)
                             .map(x -> (IntentId) x);

@@ -107,8 +107,8 @@ public class OpticalConnectivityIntentCompiler implements IntentCompiler<Optical
         log.debug("Compiling optical connectivity intent between {} and {}", src, dst);
 
         // Reserve OCh ports
-        ResourcePath srcPortPath = new ResourcePath(src.deviceId(), src.port());
-        ResourcePath dstPortPath = new ResourcePath(dst.deviceId(), dst.port());
+        ResourcePath srcPortPath = ResourcePath.discrete(src.deviceId(), src.port());
+        ResourcePath dstPortPath = ResourcePath.discrete(dst.deviceId(), dst.port());
         List<org.onosproject.net.newresource.ResourceAllocation> allocation =
                 resourceService.allocate(intent.id(), srcPortPath, dstPortPath);
         if (allocation.isEmpty()) {
@@ -182,7 +182,7 @@ public class OpticalConnectivityIntentCompiler implements IntentCompiler<Optical
 
         IndexedLambda minLambda = findFirstLambda(lambdas);
         List<ResourcePath> lambdaResources = path.links().stream()
-                .map(x -> new ResourcePath(linkKey(x.src(), x.dst())))
+                .map(x -> ResourcePath.discrete(linkKey(x.src(), x.dst())))
                 .map(x -> x.child(minLambda))
                 .collect(Collectors.toList());
 
@@ -196,7 +196,7 @@ public class OpticalConnectivityIntentCompiler implements IntentCompiler<Optical
 
     private Set<IndexedLambda> findCommonLambdasOverLinks(List<Link> links) {
         return links.stream()
-                .map(x -> new ResourcePath(linkKey(x.src(), x.dst())))
+                .map(x -> ResourcePath.discrete(linkKey(x.src(), x.dst())))
                 .map(resourceService::getAvailableResources)
                 .map(x -> Iterables.filter(x, r -> r.last() instanceof IndexedLambda))
                 .map(x -> Iterables.transform(x, r -> (IndexedLambda) r.last()))

@@ -75,12 +75,12 @@ final class ResourceDeviceListener implements DeviceListener {
     }
 
     private void registerPortResource(Device device, Port port) {
-        ResourcePath parent = new ResourcePath(device.id());
+        ResourcePath parent = ResourcePath.discrete(device.id());
         executor.submit(() -> adminService.registerResources(parent, port.number()));
     }
 
     private void unregisterPortResource(Device device, Port port) {
-        ResourcePath parent = new ResourcePath(device.id());
+        ResourcePath parent = ResourcePath.discrete(device.id());
         executor.submit(() -> adminService.unregisterResources(parent, port.number()));
     }
 }

@@ -87,7 +87,7 @@ final class ResourceLinkListener implements LinkListener {
             LinkKey linkKey = LinkKey.linkKey(link);
             adminService.registerResources(ResourcePath.ROOT, linkKey);
 
-            ResourcePath linkPath = new ResourcePath(linkKey);
+            ResourcePath linkPath = ResourcePath.discrete(linkKey);
             // register VLAN IDs against the link
             if (isEnabled(link, this::isVlanEnabled)) {
                 adminService.registerResources(linkPath, ENTIRE_VLAN_IDS);

@@ -231,7 +231,7 @@ public class ObjectiveTrackerTest {
     @Test
     public void testResourceEvent() throws Exception {
         ResourceEvent event = new ResourceEvent(RESOURCE_ADDED,
-                new ResourcePath(linkKey(link("a", 1, "b", 1))));
+                ResourcePath.discrete(linkKey(link("a", 1, "b", 1))));
         resourceListener.event(event);
 
         assertThat(

@@ -416,6 +416,8 @@ public final class KryoNamespaces {
                     BandwidthResourceAllocation.class,
                     LambdaResourceAllocation.class,
                     ResourcePath.class,
+                    ResourcePath.Discrete.class,
+                    ResourcePath.Continuous.class,
                     ResourceAllocation.class,
                     // Constraints
                     LambdaConstraint.class,

@@ -373,13 +373,13 @@ public class KryoSerializerTest {
 
     @Test
     public void testResourcePath() {
-        testSerializedEquals(new ResourcePath(LinkKey.linkKey(CP1, CP2), VLAN1));
+        testSerializedEquals(ResourcePath.discrete(LinkKey.linkKey(CP1, CP2), VLAN1));
     }
 
     @Test
     public void testResourceAllocation() {
         testSerializedEquals(new org.onosproject.net.newresource.ResourceAllocation(
-                new ResourcePath(LinkKey.linkKey(CP1, CP2), VLAN1),
+                ResourcePath.discrete(LinkKey.linkKey(CP1, CP2), VLAN1),
                 IntentId.valueOf(30)));
     }