apct-tests/perftests/utils/src/android/perftests/utils/TestUtils.java

/*
 * Copyright (C) 2021 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 android.perftests.utils;

import android.app.Instrumentation;

import androidx.annotation.NonNull;
import androidx.test.InstrumentationRegistry;

import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Supplier;

public final class TestUtils {

    /**
     * Retrieves a value that needs to be obtained on the main thread.
     *
     * <p>A simple utility method that helps to return an object from the UI thread.</p>
     *
     * @param supplier callback to be called on the UI thread to return a value
     * @param <T> Type of the value to be returned
     * @return Value returned from {@code supplier}
     */
    public static <T> T getOnMainSync(@NonNull Supplier<T> supplier) {
        final AtomicReference<T> result = new AtomicReference<>();
        final Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
        instrumentation.runOnMainSync(() -> result.set(supplier.get()));
        return result.get();
    }
}