SortedKeyedList...: Support arbitrary comparators

Signed-off-by: Samuel Holland <samuel@sholland.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/app/src/main/java/com/wireguard/android/util/SortedKeyedList.java b/app/src/main/java/com/wireguard/android/util/SortedKeyedList.java
new file mode 100644
index 00000000..b164b99d
--- /dev/null
+++ b/app/src/main/java/com/wireguard/android/util/SortedKeyedList.java
@@ -0,0 +1,22 @@
+package com.wireguard.android.util;
+
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.Set;
+
+/**
+ * A keyed list where all elements are sorted by the comparator returned by {@code comparator()}
+ * applied to their keys.
+ */
+
+public interface SortedKeyedList<K, E extends Keyed<? extends K>> extends KeyedList<K, E> {
+    Comparator<? super K> comparator();
+
+    K firstKey();
+
+    Set<K> keySet();
+
+    K lastKey();
+
+    Collection<E> values();
+}