apf: Documentation improvements and code optimizations for keepalive filters

Optimizing instruction to reduce code size of keepalive filters.

Bug: 123992088
Test: atest NetworkStackTests
Change-Id: I9ae55977c6d6740277ba55603ee957f33a97ecaa

1 files changed, 16 insertions, 0 deletions

diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index 481dbda..fedb8d1 100644
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -17,10 +17,13 @@
 package android.net.util;
 
 import android.annotation.NonNull;
+import android.util.SparseArray;
 
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.util.List;
+import java.util.function.Predicate;
+
 
 /**
  * Collection of utilities for the network stack.
@@ -65,4 +68,17 @@ public class NetworkStackUtils {
         }
         return array;
     }
+
+    /**
+     * @return True if there exists at least one element in the sparse array for which
+     * condition {@code predicate}
+     */
+    public static <T> boolean any(SparseArray<T> array, Predicate<T> predicate) {
+        for (int i = 0; i < array.size(); ++i) {
+            if (predicate.test(array.valueAt(i))) {
+                return true;
+            }
+        }
+        return false;
+    }
 }