fixes more error

wmshell/src/com/android/wm/shell/common/ShellExecutor.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.wm.shell.common;
+
+import java.lang.reflect.Array;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executor;
+import java.util.concurrent.TimeUnit;
+import java.util.function.Supplier;
+
+/**
+ * Super basic Executor interface that adds support for delayed execution and removing callbacks.
+ * Intended to wrap Handler while better-supporting testing.
+ */
+public interface ShellExecutor extends Executor {
+
+    /**
+     * Executes the given runnable. If the caller is running on the same looper as this executor,
+     * the runnable must be executed immediately.
+     */
+    @Override
+    void execute(Runnable runnable);
+
+    /**
+     * Executes the given runnable in a blocking call. If the caller is running on the same looper
+     * as this executor, the runnable must be executed immediately.
+     *
+     * @throws InterruptedException if runnable does not return in the time specified by
+     *                              {@param waitTimeout}
+     */
+    default void executeBlocking(Runnable runnable, int waitTimeout, TimeUnit waitTimeUnit)
+            throws InterruptedException {
+        final CountDownLatch latch = new CountDownLatch(1);
+        execute(() -> {
+            runnable.run();
+            latch.countDown();
+        });
+        latch.await(waitTimeout, waitTimeUnit);
+    }
+
+    /**
+     * Convenience method to execute the blocking call with a default timeout.
+     *
+     * @throws InterruptedException if runnable does not return in the time specified by
+     *                              {@param waitTimeout}
+     */
+    default void executeBlocking(Runnable runnable) throws InterruptedException {
+        executeBlocking(runnable, 2, TimeUnit.SECONDS);
+    }
+
+    /**
+     * Convenience method to execute the blocking call with a default timeout and returns a value.
+     * Waits indefinitely for a typed result from a call.
+     */
+    default <T> T executeBlockingForResult(Supplier<T> runnable, Class clazz) {
+        final T[] result = (T[]) Array.newInstance(clazz, 1);
+        final CountDownLatch latch = new CountDownLatch(1);
+        execute(() -> {
+            result[0] = runnable.get();
+            latch.countDown();
+        });
+        try {
+            latch.await();
+            return result[0];
+        } catch (InterruptedException e) {
+            return null;
+        }
+    }
+
+
+    /**
+     * See {@link android.os.Handler#postDelayed(Runnable, long)}.
+     */
+    void executeDelayed(Runnable runnable, long delayMillis);
+
+    /**
+     * See {@link android.os.Handler#removeCallbacks}.
+     */
+    void removeCallbacks(Runnable runnable);
+
+    /**
+     * See {@link android.os.Handler#hasCallbacks(Runnable)}.
+     */
+    boolean hasCallback(Runnable runnable);
+}