1 files changed, 32 insertions, 0 deletions
diff --git a/ui/src/main/java/com/wireguard/util/KeyedList.java b/ui/src/main/java/com/wireguard/util/KeyedList.java
new file mode 100644
index 00000000..c116c1da
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/util/KeyedList.java
@@ -0,0 +1,32 @@
+/*
+ * Copyright © 2017-2019 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.util;
+
+import androidx.annotation.Nullable;
+
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * A list containing elements that can be looked up by key. A {@code KeyedList} cannot contain
+ * {@code null} elements.
+ */
+
+public interface KeyedList<K, E extends Keyed<? extends K>> extends List<E> {
+    boolean containsAllKeys(Collection<K> keys);
+
+    boolean containsKey(K key);
+
+    @Nullable
+    E get(K key);
+
+    @Nullable
+    E getLast(K key);
+
+    int indexOfKey(K key);
+
+    int lastIndexOfKey(K key);
+}