Use Java 8 Map#compute when possible

Change-Id: Ida300c054449047096f355f09b3843e4934dcd18
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
index 14e37b8..4218d47 100644
--- a/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleDeviceStore.java
@@ -46,7 +46,6 @@
 import org.onosproject.net.provider.ProviderId;
 import org.onosproject.store.AbstractStore;
 import org.onlab.packet.ChassisId;
-import org.onlab.util.NewConcurrentHashMap;
 import org.slf4j.Logger;
 
 import java.util.ArrayList;
@@ -73,7 +72,6 @@
 import static com.google.common.base.Verify.verify;
 import static org.onosproject.net.device.DeviceEvent.Type.*;
 import static org.slf4j.LoggerFactory.getLogger;
-import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
 import static org.onosproject.net.DefaultAnnotations.union;
 import static org.onosproject.net.DefaultAnnotations.merge;
 
@@ -347,8 +345,7 @@
     // Gets the map of ports for the specified device; if one does not already
     // exist, it creates and registers a new one.
     private ConcurrentMap<PortNumber, Port> getPortMap(DeviceId deviceId) {
-        return createIfAbsentUnchecked(devicePorts, deviceId,
-                                       NewConcurrentHashMap.ifNeeded());
+        return devicePorts.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     private Map<ProviderId, DeviceDescriptions> getOrCreateDeviceDescriptions(
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java
index bc8805d..3706b4b 100644
--- a/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleFlowRuleStore.java
@@ -30,7 +30,6 @@
 import org.apache.felix.scr.annotations.Modified;
 import org.apache.felix.scr.annotations.Property;
 import org.apache.felix.scr.annotations.Service;
-import org.onlab.util.NewConcurrentHashMap;
 import org.onlab.util.Tools;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.flow.CompletedBatchOperation;
@@ -66,7 +65,6 @@
 import java.util.concurrent.TimeoutException;
 import java.util.concurrent.atomic.AtomicInteger;
 
-import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
 import static org.onosproject.net.flow.FlowRuleEvent.Type.RULE_REMOVED;
 import static org.slf4j.LoggerFactory.getLogger;
 
@@ -163,10 +161,6 @@
         }
     }
 
-    private static NewConcurrentHashMap<FlowId, List<StoredFlowEntry>> lazyEmptyFlowTable() {
-        return NewConcurrentHashMap.ifNeeded();
-    }
-
     /**
      * Returns the flow table for specified device.
      *
@@ -174,8 +168,7 @@
      * @return Map representing Flow Table of given device.
      */
     private ConcurrentMap<FlowId, List<StoredFlowEntry>> getFlowTable(DeviceId deviceId) {
-        return createIfAbsentUnchecked(flowEntries,
-                                       deviceId, lazyEmptyFlowTable());
+        return flowEntries.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     private List<StoredFlowEntry> getFlowEntries(DeviceId deviceId, FlowId flowId) {
@@ -317,6 +310,7 @@
         return null;
     }
 
+    @Override
     public void purgeFlowRule(DeviceId deviceId) {
         flowEntries.remove(deviceId);
     }
diff --git a/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java
index e019ed9..3489bd8 100644
--- a/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java
+++ b/core/common/src/test/java/org/onosproject/store/trivial/SimpleGroupStore.java
@@ -15,7 +15,6 @@
  */
 package org.onosproject.store.trivial;
 
-import static org.apache.commons.lang3.concurrent.ConcurrentUtils.createIfAbsentUnchecked;
 import static org.slf4j.LoggerFactory.getLogger;
 
 import java.util.ArrayList;
@@ -34,7 +33,6 @@
 import org.apache.felix.scr.annotations.Component;
 import org.apache.felix.scr.annotations.Deactivate;
 import org.apache.felix.scr.annotations.Service;
-import org.onlab.util.NewConcurrentHashMap;
 import org.onosproject.core.DefaultGroupId;
 import org.onosproject.core.GroupId;
 import org.onosproject.net.DeviceId;
@@ -99,26 +97,6 @@
         log.info("Stopped");
     }
 
-    private static NewConcurrentHashMap<GroupKey, StoredGroupEntry>
-                        lazyEmptyGroupKeyTable() {
-        return NewConcurrentHashMap.ifNeeded();
-    }
-
-    private static NewConcurrentHashMap<GroupId, StoredGroupEntry>
-                        lazyEmptyGroupIdTable() {
-        return NewConcurrentHashMap.ifNeeded();
-    }
-
-    private static NewConcurrentHashMap<GroupKey, StoredGroupEntry>
-                        lazyEmptyPendingGroupKeyTable() {
-        return NewConcurrentHashMap.ifNeeded();
-    }
-
-    private static NewConcurrentHashMap<GroupId, Group>
-                        lazyEmptyExtraneousGroupIdTable() {
-        return NewConcurrentHashMap.ifNeeded();
-    }
-
     /**
      * Returns the group key table for specified device.
      *
@@ -126,8 +104,7 @@
      * @return Map representing group key table of given device.
      */
     private ConcurrentMap<GroupKey, StoredGroupEntry> getGroupKeyTable(DeviceId deviceId) {
-        return createIfAbsentUnchecked(groupEntriesByKey,
-                                       deviceId, lazyEmptyGroupKeyTable());
+        return groupEntriesByKey.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     /**
@@ -137,8 +114,7 @@
      * @return Map representing group key table of given device.
      */
     private ConcurrentMap<GroupId, StoredGroupEntry> getGroupIdTable(DeviceId deviceId) {
-        return createIfAbsentUnchecked(groupEntriesById,
-                                       deviceId, lazyEmptyGroupIdTable());
+        return groupEntriesById.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     /**
@@ -149,8 +125,7 @@
      */
     private ConcurrentMap<GroupKey, StoredGroupEntry>
                     getPendingGroupKeyTable(DeviceId deviceId) {
-        return createIfAbsentUnchecked(pendingGroupEntriesByKey,
-                                       deviceId, lazyEmptyPendingGroupKeyTable());
+        return pendingGroupEntriesByKey.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     /**
@@ -161,9 +136,7 @@
      */
     private ConcurrentMap<GroupId, Group>
                 getExtraneousGroupIdTable(DeviceId deviceId) {
-        return createIfAbsentUnchecked(extraneousGroupEntriesById,
-                                       deviceId,
-                                       lazyEmptyExtraneousGroupIdTable());
+        return extraneousGroupEntriesById.computeIfAbsent(deviceId, k -> new ConcurrentHashMap<>());
     }
 
     /**