From 928bb445efe0a1c27b950dad4de749c705b0c346 Mon Sep 17 00:00:00 2001
From: Kweku Adams <kwekua@google.com>
Date: Wed, 14 Sep 2022 16:37:45 +0000
Subject: [PATCH] Return the previous value when adding a new one.

It would be nice to be able to get the previous value when
adding a new one without having to do a separate get() call.

Bug: 243987091
Test: atest CtsUtilTestCases:SparseArrayMapTest
Change-Id: I763c08443b9376f5142abd1aa817f1c61990f4be
---
 core/api/test-current.txt                  |  2 +-
 core/java/android/util/SparseArrayMap.java | 12 +++++++++---
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/core/api/test-current.txt b/core/api/test-current.txt
index deb5aca53b78d..f780e6f3b39b5 100644
--- a/core/api/test-current.txt
+++ b/core/api/test-current.txt
@@ -2709,7 +2709,7 @@ package android.util {
 
   public class SparseArrayMap<K, V> {
     ctor public SparseArrayMap();
-    method public void add(int, @NonNull K, @Nullable V);
+    method public V add(int, @NonNull K, @Nullable V);
     method public void clear();
     method public boolean contains(int, @NonNull K);
     method public void delete(int);
diff --git a/core/java/android/util/SparseArrayMap.java b/core/java/android/util/SparseArrayMap.java
index e5bb9f453a889..1a2c4df96b367 100644
--- a/core/java/android/util/SparseArrayMap.java
+++ b/core/java/android/util/SparseArrayMap.java
@@ -34,14 +34,20 @@ import java.util.function.Consumer;
 public class SparseArrayMap<K, V> {
     private final SparseArray<ArrayMap<K, V>> mData = new SparseArray<>();
 
-    /** Add an entry associating obj with the int-K pair. */
-    public void add(int key, @NonNull K mapKey, @Nullable V obj) {
+    /**
+     * Add an entry associating obj with the int-K pair.
+     *
+     * @return the previous value associated with key, or null if there was no mapping for key.
+     * (A null return can also indicate that the map previously associated null with key, if the
+     * implementation supports null values.)
+     */
+    public V add(int key, @NonNull K mapKey, @Nullable V obj) {
         ArrayMap<K, V> data = mData.get(key);
         if (data == null) {
             data = new ArrayMap<>();
             mData.put(key, data);
         }
-        data.put(mapKey, obj);
+        return data.put(mapKey, obj);
     }
 
     /** Remove all entries from the map. */