Save memory consumption by avoding unnecessary instantiation

Change-Id: I7ce66c11136653fabc490aa7f33fdadf4454d2cc

@@ -18,7 +18,7 @@ package org.onosproject.segmentrouting.grouphandler;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
@@ -95,8 +95,8 @@ public class PolicyGroupHandler extends DefaultGroupHandler {
                                     new GroupBucketIdentifier(label, sp);
                             PolicyGroupIdentifier key = new
                                     PolicyGroupIdentifier(id,
-                                                          Arrays.asList(param),
-                                                          Arrays.asList(bucketId));
+                                                          Collections.singletonList(param),
+                                                          Collections.singletonList(bucketId));
                             TrafficTreatment.Builder tBuilder =
                                     DefaultTrafficTreatment.builder();
                             tBuilder.setOutput(sp)
@@ -122,8 +122,8 @@ public class PolicyGroupHandler extends DefaultGroupHandler {
                                                               previousGroupkey);
                             PolicyGroupIdentifier key = new
                                     PolicyGroupIdentifier(id,
-                                                          Arrays.asList(param),
-                                                          Arrays.asList(bucketId));
+                                                          Collections.singletonList(param),
+                                                          Collections.singletonList(bucketId));
                             // Add to group dependency list
                             dependentGroups.put(previousGroupkey, key);
                             previousGroupkey = key;
@@ -283,8 +283,8 @@ public class PolicyGroupHandler extends DefaultGroupHandler {
                                     new GroupBucketIdentifier(label, sp);
                             PolicyGroupIdentifier key = new
                                     PolicyGroupIdentifier(id,
-                                                          Arrays.asList(param),
-                                                          Arrays.asList(bucketId));
+                                                          Collections.singletonList(param),
+                                                          Collections.singletonList(bucketId));
                             previousGroupkey = key;
                         } else {
                             // Intermediate Groups
@@ -293,8 +293,8 @@ public class PolicyGroupHandler extends DefaultGroupHandler {
                                                               previousGroupkey);
                             PolicyGroupIdentifier key = new
                                     PolicyGroupIdentifier(id,
-                                                          Arrays.asList(param),
-                                                          Arrays.asList(bucketId));
+                                                          Collections.singletonList(param),
+                                                          Collections.singletonList(bucketId));
                             previousGroupkey = key;
                         }
                     }

@@ -16,6 +16,7 @@
 package org.onosproject.net.intent;
 
 import java.util.Arrays;
+import java.util.Collections;
 
 import org.junit.Test;
 import org.onosproject.net.ConnectPoint;
@@ -93,7 +94,7 @@ public class PathIntentTest extends ConnectivityIntentTest {
                 .appId(APPID)
                 .selector(MATCH)
                 .treatment(NOP)
-                .path(new DefaultPath(provider1, Arrays.asList(link1), cost))
+                .path(new DefaultPath(provider1, Collections.singletonList(link1), cost))
                 .build();
     }
 

@@ -17,8 +17,8 @@ package org.onosproject.net.group.impl;
 
 import static org.slf4j.LoggerFactory.getLogger;
 
-import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.Set;
 
@@ -261,7 +261,7 @@ public class GroupManager
                                                 group.type(),
                                                 group.buckets());
                 groupOps = new GroupOperations(
-                                          Arrays.asList(groupAddOp));
+                        Collections.singletonList(groupAddOp));
                 groupProvider.performGroupOperation(group.deviceId(), groupOps);
                 break;
 
@@ -273,7 +273,7 @@ public class GroupManager
                                                 group.type(),
                                                 group.buckets());
                 groupOps = new GroupOperations(
-                                   Arrays.asList(groupModifyOp));
+                        Collections.singletonList(groupModifyOp));
                 groupProvider.performGroupOperation(group.deviceId(), groupOps);
                 break;
 
@@ -284,7 +284,7 @@ public class GroupManager
                         createDeleteGroupOperation(group.id(),
                                                 group.type());
                 groupOps = new GroupOperations(
-                                   Arrays.asList(groupDeleteOp));
+                        Collections.singletonList(groupDeleteOp));
                 groupProvider.performGroupOperation(group.deviceId(), groupOps);
                 break;
 
@@ -335,7 +335,7 @@ public class GroupManager
                                                             group.type(),
                                                             group.buckets());
                     GroupOperations groupOps = new GroupOperations(
-                                              Arrays.asList(groupAddOp));
+                            Collections.singletonList(groupAddOp));
                     gp.performGroupOperation(group.deviceId(), groupOps);
                     break;
                 default:

@@ -44,7 +44,7 @@ import org.onosproject.net.intent.LinkCollectionIntent;
 import org.onosproject.net.resource.LinkResourceAllocations;
 
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -104,7 +104,7 @@ public class LinkCollectionIntentCompiler implements IntentCompiler<LinkCollecti
         for (DeviceId deviceId: outputPorts.keys()) {
             rules.addAll(createRules(intent, deviceId, inputPorts.get(deviceId), outputPorts.get(deviceId)));
         }
-        return Arrays.asList(new FlowRuleIntent(appId, rules, intent.resources()));
+        return Collections.singletonList(new FlowRuleIntent(appId, rules, intent.resources()));
     }
 
     private List<FlowRule> createRules(LinkCollectionIntent intent, DeviceId deviceId,

@@ -52,7 +52,7 @@ import org.onosproject.net.resource.ResourceAllocation;
 import org.onosproject.net.resource.ResourceType;
 import org.slf4j.Logger;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
@@ -86,7 +86,7 @@ public class MplsPathIntentCompiler implements IntentCompiler<MplsPathIntent> {
         LinkResourceAllocations allocations = assignMplsLabel(intent);
         List<FlowRule> rules = generateRules(intent, allocations);
 
-        return Arrays.asList(new FlowRuleIntent(appId, rules, intent.resources()));
+        return Collections.singletonList(new FlowRuleIntent(appId, rules, intent.resources()));
     }
 
     @Activate

@@ -15,7 +15,7 @@
  */
 package org.onosproject.net.intent.impl.compiler;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -110,7 +110,7 @@ public class MultiPointToSinglePointIntentCompiler
                 .constraints(intent.constraints())
                 .build();
 
-        return Arrays.asList(result);
+        return Collections.singletonList(result);
     }
 
     /**

@@ -46,7 +46,7 @@ import org.onosproject.net.resource.ResourceAllocation;
 import org.onosproject.net.resource.ResourceType;
 import org.onosproject.net.topology.TopologyService;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
@@ -88,7 +88,8 @@ public class OpticalPathIntentCompiler implements IntentCompiler<OpticalPathInte
                                 Set<LinkResourceAllocations> resources) {
         LinkResourceAllocations allocations = assignWavelength(intent);
 
-        return Arrays.asList(new FlowRuleIntent(appId, createRules(intent, allocations), intent.resources()));
+        return Collections.singletonList(
+                new FlowRuleIntent(appId, createRules(intent, allocations), intent.resources()));
     }
 
     private LinkResourceAllocations assignWavelength(OpticalPathIntent intent) {

@@ -38,7 +38,7 @@ import org.onosproject.net.intent.PathIntent;
 import org.onosproject.net.resource.LinkResourceAllocations;
 
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
@@ -80,7 +80,7 @@ public class PathIntentCompiler implements IntentCompiler<PathIntent> {
             rules.add(rule);
         }
 
-        return Arrays.asList(new FlowRuleIntent(appId, null, rules, intent.resources()));
+        return Collections.singletonList(new FlowRuleIntent(appId, null, rules, intent.resources()));
     }
 
     private FlowRule createFlowRule(TrafficSelector originalSelector, TrafficTreatment originalTreatment,

@@ -15,7 +15,7 @@
  */
 package org.onosproject.net.intent.impl.compiler;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -77,6 +77,6 @@ public class SinglePointToMultiPointIntentCompiler
                 .constraints(intent.constraints())
                 .build();
 
-        return Arrays.asList(result);
+        return Collections.singletonList(result);
     }
 }

@@ -63,7 +63,6 @@ import org.onosproject.net.provider.ProviderId;
 import org.onosproject.store.trivial.impl.SimpleFlowRuleStore;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -412,7 +411,7 @@ public class FlowRuleManagerTest {
 
         @Override
         public Iterable<Device> getDevices() {
-            return Arrays.asList(DEV);
+            return Collections.singletonList(DEV);
         }
 
         @Override

@@ -258,9 +258,9 @@ public class GroupManagerTest {
                                         DID,
                                         Group.Type.SELECT,
                                         createdGroup.buckets());
-        List<Group> groupEntries = Arrays.asList(createdGroup);
+        List<Group> groupEntries = Collections.singletonList(createdGroup);
         providerService.pushGroupMetrics(DID, groupEntries);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_ADDED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_ADDED));
     }
 
     // Test group add bucket operations
@@ -296,15 +296,15 @@ public class GroupManagerTest {
                                        addKey,
                                        appId);
         GroupBuckets updatedBuckets = new GroupBuckets(buckets);
-        List<GroupOperation> expectedGroupOps = Arrays.asList(
+        List<GroupOperation> expectedGroupOps = Collections.singletonList(
                 GroupOperation.createModifyGroupOperation(createdGroup.id(),
                         Group.Type.SELECT,
                         updatedBuckets));
         internalProvider.validate(DID, expectedGroupOps);
         Group existingGroup = groupService.getGroup(DID, addKey);
-        List<Group> groupEntries = Arrays.asList(existingGroup);
+        List<Group> groupEntries = Collections.singletonList(existingGroup);
         providerService.pushGroupMetrics(DID, groupEntries);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_UPDATED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_UPDATED));
     }
 
     // Test group remove bucket operations
@@ -340,15 +340,15 @@ public class GroupManagerTest {
                                             removeKey,
                                             appId);
         GroupBuckets updatedBuckets = new GroupBuckets(buckets);
-        List<GroupOperation> expectedGroupOps = Arrays.asList(
+        List<GroupOperation> expectedGroupOps = Collections.singletonList(
                 GroupOperation.createModifyGroupOperation(createdGroup.id(),
                         Group.Type.SELECT,
                         updatedBuckets));
         internalProvider.validate(DID, expectedGroupOps);
         Group existingGroup = groupService.getGroup(DID, removeKey);
-        List<Group> groupEntries = Arrays.asList(existingGroup);
+        List<Group> groupEntries = Collections.singletonList(existingGroup);
         providerService.pushGroupMetrics(DID, groupEntries);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_UPDATED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_UPDATED));
     }
 
     // Test group remove operations
@@ -356,13 +356,13 @@ public class GroupManagerTest {
         GroupKey currKey = new DefaultGroupKey("group1RemoveBuckets".getBytes());
         Group existingGroup = groupService.getGroup(DID, currKey);
         groupService.removeGroup(DID, currKey, appId);
-        List<GroupOperation> expectedGroupOps = Arrays.asList(
+        List<GroupOperation> expectedGroupOps = Collections.singletonList(
                 GroupOperation.createDeleteGroupOperation(existingGroup.id(),
                         Group.Type.SELECT));
         internalProvider.validate(DID, expectedGroupOps);
         List<Group> groupEntries = Collections.emptyList();
         providerService.pushGroupMetrics(DID, groupEntries);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_REMOVED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_REMOVED));
     }
 
     /**
@@ -423,7 +423,7 @@ public class GroupManagerTest {
                         createdGroup.type(),
                         createdGroup.buckets());
         providerService.groupOperationFailed(DID, groupAddOp);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_ADD_FAILED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_ADD_FAILED));
 
         // Group Mod failure test
         groupService.addGroup(newGroupDesc);
@@ -435,7 +435,7 @@ public class GroupManagerTest {
                         createdGroup.type(),
                         createdGroup.buckets());
         providerService.groupOperationFailed(DID, groupModOp);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_UPDATE_FAILED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_UPDATE_FAILED));
 
         // Group Delete failure test
         groupService.addGroup(newGroupDesc);
@@ -446,7 +446,7 @@ public class GroupManagerTest {
                 createDeleteGroupOperation(createdGroup.id(),
                         createdGroup.type());
         providerService.groupOperationFailed(DID, groupDelOp);
-        internalListener.validateEvent(Arrays.asList(GroupEvent.Type.GROUP_REMOVE_FAILED));
+        internalListener.validateEvent(Collections.singletonList(GroupEvent.Type.GROUP_REMOVE_FAILED));
 
     }
 

@@ -46,7 +46,6 @@ import org.onosproject.net.intent.Key;
 import org.onosproject.net.resource.LinkResourceAllocations;
 import org.onosproject.store.trivial.impl.SimpleIntentStore;
 
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -151,7 +150,7 @@ public class IntentManagerTest {
     private static class MockInstallableIntent extends FlowRuleIntent {
 
         public MockInstallableIntent() {
-            super(APPID, Arrays.asList(new MockFlowRule(100)));
+            super(APPID, Collections.singletonList(new MockFlowRule(100)));
         }
     }
 

@@ -38,7 +38,7 @@ import org.onosproject.net.resource.BandwidthResource;
 import org.onosproject.net.resource.LambdaResource;
 import org.onosproject.net.resource.LinkResourceService;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -228,8 +228,8 @@ public class PointToPointIntentCompilerTest extends AbstractIntentTest {
 
         final LinkResourceService resourceService =
                 IntentTestsMocks.MockResourceService.makeBandwidthResourceService(1000.0);
-        final List<Constraint> constraints = Arrays.asList(
-                new BandwidthConstraint(new BandwidthResource(Bandwidth.bps(100.0))));
+        final List<Constraint> constraints =
+                Collections.singletonList(new BandwidthConstraint(new BandwidthResource(Bandwidth.bps(100.0))));
 
         final PointToPointIntent intent = makeIntent("s1", "s3", constraints);
 
@@ -250,8 +250,8 @@ public class PointToPointIntentCompilerTest extends AbstractIntentTest {
 
         final LinkResourceService resourceService =
                 IntentTestsMocks.MockResourceService.makeBandwidthResourceService(10.0);
-        final List<Constraint> constraints = Arrays.asList(
-                new BandwidthConstraint(new BandwidthResource(Bandwidth.bps(100.0))));
+        final List<Constraint> constraints =
+                Collections.singletonList(new BandwidthConstraint(new BandwidthResource(Bandwidth.bps(100.0))));
 
         try {
             final PointToPointIntent intent = makeIntent("s1", "s3", constraints);
@@ -274,7 +274,8 @@ public class PointToPointIntentCompilerTest extends AbstractIntentTest {
     @Test
     public void testLambdaConstrainedIntentSuccess() {
 
-        final List<Constraint> constraints = Arrays.asList(new LambdaConstraint(LambdaResource.valueOf(1)));
+        final List<Constraint> constraints =
+                Collections.singletonList(new LambdaConstraint(LambdaResource.valueOf(1)));
         final LinkResourceService resourceService =
                 IntentTestsMocks.MockResourceService.makeLambdaResourceService(1);
 
@@ -297,7 +298,8 @@ public class PointToPointIntentCompilerTest extends AbstractIntentTest {
     @Test
     public void testLambdaConstrainedIntentFailure() {
 
-        final List<Constraint> constraints = Arrays.asList(new LambdaConstraint(LambdaResource.valueOf(1)));
+        final List<Constraint> constraints =
+                Collections.singletonList(new LambdaConstraint(LambdaResource.valueOf(1)));
         final LinkResourceService resourceService =
                 IntentTestsMocks.MockResourceService.makeBandwidthResourceService(10.0);
         try {

@@ -40,7 +40,7 @@ import org.onosproject.net.intent.impl.IntentProcessor;
 import org.onosproject.net.provider.ProviderId;
 import org.onosproject.store.Timestamp;
 
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -70,7 +70,7 @@ public class CompilingTest {
     private final ConnectPoint cp3 = new ConnectPoint(deviceId("2"), portNumber(1));
     private final ConnectPoint cp4 = new ConnectPoint(deviceId("2"), portNumber(2));
 
-    private final List<Link> links = Arrays.asList(new DefaultLink(pid, cp2, cp4, DIRECT));
+    private final List<Link> links = Collections.singletonList(new DefaultLink(pid, cp2, cp4, DIRECT));
     private final Path path = new DefaultPath(pid, links, 10);
 
     private PointToPointIntent input;
@@ -118,7 +118,7 @@ public class CompilingTest {
     public void testMoveToNextPhaseWithoutError() {
         IntentData pending = new IntentData(input, INSTALL_REQ, version);
 
-        expect(processor.compile(input, null)).andReturn(Arrays.asList(compiled));
+        expect(processor.compile(input, null)).andReturn(Collections.singletonList(compiled));
         replay(processor);
 
         Compiling sut = new Compiling(processor, pending, Optional.empty());

@@ -78,7 +78,6 @@ import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Dictionary;
 import java.util.HashSet;
@@ -388,7 +387,7 @@ public class DistributedFlowRuleStore
     @Override
     public void storeFlowRule(FlowRule rule) {
         storeBatch(new FlowRuleBatchOperation(
-                Arrays.asList(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule)),
+                Collections.singletonList(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule)),
                 rule.deviceId(), idGenerator.getNewId()));
     }
 
@@ -516,7 +515,7 @@ public class DistributedFlowRuleStore
     public void deleteFlowRule(FlowRule rule) {
         storeBatch(
                 new FlowRuleBatchOperation(
-                        Arrays.asList(
+                        Collections.singletonList(
                                 new FlowRuleBatchEntry(
                                         FlowRuleOperation.REMOVE,
                                         rule)), rule.deviceId(), idGenerator.getNewId()));

@@ -71,7 +71,6 @@ import org.onosproject.store.serializers.impl.DistributedStoreSerializers;
 import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 
-import java.util.Arrays;
 import java.util.Collections;
 import java.util.Dictionary;
 import java.util.HashSet;
@@ -378,7 +377,7 @@ public class NewDistributedFlowRuleStore
     @Override
     public void storeFlowRule(FlowRule rule) {
         storeBatch(new FlowRuleBatchOperation(
-                Arrays.asList(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule)),
+                Collections.singletonList(new FlowRuleBatchEntry(FlowRuleOperation.ADD, rule)),
                 rule.deviceId(), idGenerator.getNewId()));
     }
 
@@ -484,7 +483,7 @@ public class NewDistributedFlowRuleStore
     public void deleteFlowRule(FlowRule rule) {
         storeBatch(
                 new FlowRuleBatchOperation(
-                        Arrays.asList(
+                        Collections.singletonList(
                                 new FlowRuleBatchEntry(
                                         FlowRuleOperation.REMOVE,
                                         rule)), rule.deviceId(), idGenerator.getNewId()));

@@ -20,6 +20,7 @@ import static org.onosproject.net.DeviceId.deviceId;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
 
@@ -307,7 +308,7 @@ public class SimpleGroupStoreTest {
         PortNumber[] newNeighborPorts = {PortNumber.portNumber(41),
                                          PortNumber.portNumber(42)};
         List<PortNumber> newOutPorts = new ArrayList<PortNumber>();
-        newOutPorts.addAll(Arrays.asList(newNeighborPorts[0]));
+        newOutPorts.addAll(Collections.singletonList(newNeighborPorts[0]));
 
         List<GroupBucket> toAddBuckets = new ArrayList<GroupBucket>();
         for (PortNumber portNumber: newOutPorts) {

@@ -73,7 +73,6 @@ import org.onosproject.net.group.GroupService;
 import org.slf4j.Logger;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
@@ -313,7 +312,7 @@ public class SpringOpenTTP extends AbstractHandlerBehaviour
             log.warn("Unsupported Group type {}", group.type());
             return;
         }
-        GroupBuckets bucketsToAdd = new GroupBuckets(Arrays.asList(bucket));
+        GroupBuckets bucketsToAdd = new GroupBuckets(Collections.singletonList(bucket));
         groupService.addBucketsToGroup(deviceId, key, bucketsToAdd, key, appId);
     }
 
@@ -339,7 +338,7 @@ public class SpringOpenTTP extends AbstractHandlerBehaviour
                 log.warn("Unsupported Group type {}", group.type());
                 return;
             }
-            GroupBuckets removeBuckets = new GroupBuckets(Arrays.asList(bucket));
+            GroupBuckets removeBuckets = new GroupBuckets(Collections.singletonList(bucket));
             groupService.removeBucketsFromGroup(deviceId, key, removeBuckets, key, appId);
         }
     }