Prevent ConcurrentModificationExceptions
Use sets backed by ConcurrentHashMaps instead of HashSets, and
CopyOnWriteArrayLists instead of ArrayLists, to prevent concurrent
exceptions if listeners try to remove themselves in callbacks while
iterating over the listeners.
Bug:16325026
Change-Id: I55e081eda6ba19fa466bbf019c648bbdaf833c33
diff --git a/telecomm/java/android/telecomm/Connection.java b/telecomm/java/android/telecomm/Connection.java
index 3ecb4cb..78c34a1 100644
--- a/telecomm/java/android/telecomm/Connection.java
+++ b/telecomm/java/android/telecomm/Connection.java
@@ -32,7 +32,7 @@
import java.util.Collections;
import java.util.List;
import java.util.Set;
-import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.ConcurrentHashMap;
/**
* Represents a connection to a remote endpoint that carries voice traffic.
@@ -448,7 +448,13 @@
}
};
- private final Set<Listener> mListeners = new CopyOnWriteArraySet<>();
+ /**
+ * ConcurrentHashMap constructor params: 8 is initial table size, 0.9f is
+ * load factor before resizing, 1 means we only expect a single thread to
+ * access the map so make only a single shard
+ */
+ private final Set<Listener> mListeners = Collections.newSetFromMap(
+ new ConcurrentHashMap<Listener, Boolean>(8, 0.9f, 1));
private final List<Connection> mChildConnections = new ArrayList<>();
private final List<Connection> mUnmodifiableChildConnections =
Collections.unmodifiableList(mChildConnections);
@@ -587,7 +593,9 @@
* @hide
*/
public final Connection removeConnectionListener(Listener l) {
- mListeners.remove(l);
+ if (l != null) {
+ mListeners.remove(l);
+ }
return this;
}
@@ -874,13 +882,8 @@
* Tears down the Connection object.
*/
public final void destroy() {
- // It is possible that onDestroy() will trigger the listener to remove itself which will
- // result in a concurrent modification exception. To counteract this we make a copy of the
- // listeners and iterate on that.
- for (Listener l : new ArrayList<>(mListeners)) {
- if (mListeners.contains(l)) {
- l.onDestroyed(this);
- }
+ for (Listener l : mListeners) {
+ l.onDestroyed(this);
}
}