Refactor CompareResult<> class and its call sites

Move all corner case logic from call sites to CompareResult's implementation,
add a constructor to directly do the comparison.

Test: runtest frameworks-core -c android.net.LinkPropertiesTest
Change-Id: I95bba82ec38d295b18c49c025dffab5f17271cbd

1 files changed, 23 insertions, 49 deletions

diff --git a/core/java/android/net/LinkProperties.java b/core/java/android/net/LinkProperties.java
index f527f77ddd7c..2c9fb23e077a 100644
--- a/core/java/android/net/LinkProperties.java
+++ b/core/java/android/net/LinkProperties.java
@@ -70,8 +70,23 @@ public final class LinkProperties implements Parcelable {
      * @hide
      */
     public static class CompareResult<T> {
-        public List<T> removed = new ArrayList<T>();
-        public List<T> added = new ArrayList<T>();
+        public final List<T> removed = new ArrayList<T>();
+        public final List<T> added = new ArrayList<T>();
+
+        public CompareResult() {}
+
+        public CompareResult(Collection<T> oldItems, Collection<T> newItems) {
+            if (oldItems != null) {
+                removed.addAll(oldItems);
+            }
+            if (newItems != null) {
+                for (T newItem : newItems) {
+                    if (!removed.remove(newItem)) {
+                        added.add(newItem);
+                    }
+                }
+            }
+        }
 
         @Override
         public String toString() {
@@ -1000,17 +1015,8 @@ public final class LinkProperties implements Parcelable {
          * are in target but not in mLinkAddresses are placed in the
          * addedAddresses.
          */
-        CompareResult<LinkAddress> result = new CompareResult<LinkAddress>();
-        result.removed = new ArrayList<LinkAddress>(mLinkAddresses);
-        result.added.clear();
-        if (target != null) {
-            for (LinkAddress newAddress : target.getLinkAddresses()) {
-                if (! result.removed.remove(newAddress)) {
-                    result.added.add(newAddress);
-                }
-            }
-        }
-        return result;
+        return new CompareResult<>(mLinkAddresses,
+                target != null ? target.getLinkAddresses() : null);
     }
 
     /**
@@ -1029,18 +1035,7 @@ public final class LinkProperties implements Parcelable {
          * are in target but not in mDnses are placed in the
          * addedAddresses.
          */
-        CompareResult<InetAddress> result = new CompareResult<InetAddress>();
-
-        result.removed = new ArrayList<InetAddress>(mDnses);
-        result.added.clear();
-        if (target != null) {
-            for (InetAddress newAddress : target.getDnsServers()) {
-                if (! result.removed.remove(newAddress)) {
-                    result.added.add(newAddress);
-                }
-            }
-        }
-        return result;
+        return new CompareResult<>(mDnses, target != null ? target.getDnsServers() : null);
     }
 
     /**
@@ -1058,18 +1053,7 @@ public final class LinkProperties implements Parcelable {
          * leaving the routes that are different. And route address which
          * are in target but not in mRoutes are placed in added.
          */
-        CompareResult<RouteInfo> result = new CompareResult<RouteInfo>();
-
-        result.removed = getAllRoutes();
-        result.added.clear();
-        if (target != null) {
-            for (RouteInfo r : target.getAllRoutes()) {
-                if (! result.removed.remove(r)) {
-                    result.added.add(r);
-                }
-            }
-        }
-        return result;
+        return new CompareResult<>(getAllRoutes(), target != null ? target.getAllRoutes() : null);
     }
 
     /**
@@ -1087,18 +1071,8 @@ public final class LinkProperties implements Parcelable {
          * leaving the interface names that are different. And interface names which
          * are in target but not in this are placed in added.
          */
-        CompareResult<String> result = new CompareResult<String>();
-
-        result.removed = getAllInterfaceNames();
-        result.added.clear();
-        if (target != null) {
-            for (String r : target.getAllInterfaceNames()) {
-                if (! result.removed.remove(r)) {
-                    result.added.add(r);
-                }
-            }
-        }
-        return result;
+        return new CompareResult<>(getAllInterfaceNames(),
+                target != null ? target.getAllInterfaceNames() : null);
     }