1 files changed, 38 insertions, 0 deletions
diff --git a/mojo/public/java/system/src/org/chromium/mojo/system/Watcher.java b/mojo/public/java/system/src/org/chromium/mojo/system/Watcher.java
new file mode 100644
index 0000000000..9c70161067
--- /dev/null
+++ b/mojo/public/java/system/src/org/chromium/mojo/system/Watcher.java
@@ -0,0 +1,38 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.mojo.system;
+
+import org.chromium.mojo.system.Core.HandleSignals;
+
+/**
+ * Watches a handle for signals being satisfied.
+ */
+public interface Watcher {
+    /**
+     * Callback passed to {@link Watcher#start}.
+     */
+    public interface Callback {
+        /**
+         * Called when the handle is ready.
+         */
+        public void onResult(int result);
+    }
+
+    /**
+     * Starts watching a handle.
+     */
+    int start(Handle handle, HandleSignals signals, Callback callback);
+
+    /**
+     * Cancels an already-started watch.
+     */
+    void cancel();
+
+    /**
+     * Destroys the underlying implementation. Other methods will fail after destroy has been
+     * called.
+     */
+    void destroy();
+}