Synchronize on package-private XplatMonitor classes instead of `Int…

…eger` instances, etc.

(followup to cl/645331066 now that cl/645490884, cl/653538661, and cl/655485586 have landed)

RELNOTES=n/a
PiperOrigin-RevId: 645481013

android/guava-testlib/src/com/google/common/testing/TearDownStack.java

@@ -41,7 +41,7 @@
 public class TearDownStack implements TearDownAccepter {
   private static final Logger logger = Logger.getLogger(TearDownStack.class.getName());
 
-  @VisibleForTesting final Object lock = new Object();
+  @VisibleForTesting final XplatMonitor lock = new XplatMonitor();
 
   @GuardedBy("lock")
   final LinkedList<TearDown> stack = new LinkedList<>();

android/guava-testlib/src/com/google/common/testing/TestLogHandler.java

@@ -55,7 +55,7 @@
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 public class TestLogHandler extends Handler {
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   /** We will keep a private list of all logged records */
   @GuardedBy("lock")

android/guava-testlib/src/com/google/common/testing/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.testing;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

android/guava-tests/test/com/google/common/collect/SynchronizedDequeTest.java

@@ -39,7 +39,7 @@ protected Deque<String> create() {
 
   private static final class TestDeque<E> implements Deque<E> {
     private final Deque<E> delegate = Lists.newLinkedList();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     public boolean offer(E o) {

android/guava-tests/test/com/google/common/collect/SynchronizedMapTest.java

@@ -36,7 +36,7 @@
  * @author Mike Bostock
  */
 public class SynchronizedMapTest extends TestCase {
-  public final Object mutex = new Integer(1); // something Serializable
+  public final Object mutex = new XplatMonitor(); // something Serializable
 
   protected <K, V> Map<K, V> create() {
     TestMap<K, V> inner = new TestMap<>(new HashMap<K, V>(), mutex);

android/guava-tests/test/com/google/common/collect/SynchronizedMultimapTest.java

@@ -75,7 +75,7 @@ protected SetMultimap<String, String> create(Entry<String, String>[] entries) {
   private static final class TestMultimap<K, V> extends ForwardingSetMultimap<K, V>
       implements Serializable {
     final SetMultimap<K, V> delegate = HashMultimap.create();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     protected SetMultimap<K, V> delegate() {

android/guava-tests/test/com/google/common/collect/SynchronizedSetTest.java

@@ -38,7 +38,7 @@
  */
 public class SynchronizedSetTest extends TestCase {
 
-  public static final Object MUTEX = new Integer(1); // something Serializable
+  public static final Object MUTEX = new XplatMonitor(); // something Serializable
 
   public static Test suite() {
     return SetTestSuiteBuilder.using(

android/guava-tests/test/com/google/common/collect/SynchronizedTableTest.java

@@ -25,7 +25,7 @@
 public class SynchronizedTableTest extends AbstractTableTest<Character> {
   private static final class TestTable<R, C, V> implements Table<R, C, V>, Serializable {
     final Table<R, C, V> delegate = HashBasedTable.create();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     public String toString() {

android/guava-tests/test/com/google/common/util/concurrent/FutureCallbackTest.java

@@ -62,7 +62,7 @@ public void testCancel() {
     SettableFuture<String> f = SettableFuture.create();
     FutureCallback<String> callback =
         new FutureCallback<String>() {
-          private final Object monitor = new Object();
+          private final XplatMonitor monitor = new XplatMonitor();
           private boolean called = false;
 
           @Override
@@ -183,7 +183,7 @@ private final class MockCallback implements FutureCallback<String> {
     @Nullable private String value = null;
     @Nullable private Throwable failure = null;
     private boolean wasCalled = false;
-    private final Object monitor = new Object();
+    private final XplatMonitor monitor = new XplatMonitor();
 
     MockCallback(String expectedValue) {
       this.value = expectedValue;

android/guava/src/com/google/common/base/Suppliers.java

@@ -120,8 +120,7 @@ public String toString() {
 
   @VisibleForTesting
   static class MemoizingSupplier<T extends @Nullable Object> implements Supplier<T>, Serializable {
-    private final Object lock =
-        new Integer(1); // something serializable
+    private final XplatMonitor lock = new XplatMonitor();
 
     final Supplier<T> delegate;
     transient volatile boolean initialized;
@@ -163,7 +162,7 @@ public String toString() {
 
   @VisibleForTesting
   static class NonSerializableMemoizingSupplier<T extends @Nullable Object> implements Supplier<T> {
-    private final Object lock = new Object();
+    private final XplatMonitor lock = new XplatMonitor();
 
     @SuppressWarnings("UnnecessaryLambda") // Must be a fixed singleton object
     private static final Supplier<Void> SUCCESSFULLY_COMPUTED =
@@ -275,8 +274,7 @@ public String toString() {
   @SuppressWarnings("GoodTime") // lots of violations
   static class ExpiringMemoizingSupplier<T extends @Nullable Object>
       implements Supplier<T>, Serializable {
-    private final Object lock =
-        new Integer(1); // something serializable
+    private final XplatMonitor lock = new XplatMonitor();
 
     final Supplier<T> delegate;
     final long durationNanos;

android/guava/src/com/google/common/base/XplatMonitor.java

@@ -0,0 +1,15 @@
+package com.google.common.base;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * Using this class instead of Object will allow J2kt to substitute monitors in a way that works for
+ * Kotlin native. This class is marked as Serializable so it can be "just" included in serializable
+ * classes despite this not making much sense.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

android/guava/src/com/google/common/collect/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.collect;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

android/guava/src/com/google/common/io/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.io;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

android/guava/src/com/google/common/util/concurrent/DirectExecutorService.java

@@ -29,7 +29,7 @@
 final class DirectExecutorService extends AbstractListeningExecutorService {
 
   /** Lock used whenever accessing the state variables (runningTasks, shutdown) of the executor */
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   /*
    * Conceptually, these two variables describe the executor being in

android/guava/src/com/google/common/util/concurrent/LazyLogger.java

@@ -22,7 +22,7 @@
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 final class LazyLogger {
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   private final String loggerName;
   private volatile @Nullable Logger logger;

android/guava/src/com/google/common/util/concurrent/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.util.concurrent;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

guava-testlib/src/com/google/common/testing/TearDownStack.java

@@ -41,7 +41,7 @@
 public class TearDownStack implements TearDownAccepter {
   private static final Logger logger = Logger.getLogger(TearDownStack.class.getName());
 
-  @VisibleForTesting final Object lock = new Object();
+  @VisibleForTesting final XplatMonitor lock = new XplatMonitor();
 
   @GuardedBy("lock")
   final LinkedList<TearDown> stack = new LinkedList<>();

guava-testlib/src/com/google/common/testing/TestLogHandler.java

@@ -55,7 +55,7 @@
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 public class TestLogHandler extends Handler {
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   /** We will keep a private list of all logged records */
   @GuardedBy("lock")

guava-testlib/src/com/google/common/testing/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.testing;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

guava-tests/test/com/google/common/collect/SynchronizedDequeTest.java

@@ -39,7 +39,7 @@ protected Deque<String> create() {
 
   private static final class TestDeque<E> implements Deque<E> {
     private final Deque<E> delegate = Lists.newLinkedList();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     public boolean offer(E o) {

guava-tests/test/com/google/common/collect/SynchronizedMapTest.java

@@ -36,7 +36,7 @@
  * @author Mike Bostock
  */
 public class SynchronizedMapTest extends TestCase {
-  public final Object mutex = new Integer(1); // something Serializable
+  public final Object mutex = new XplatMonitor(); // something Serializable
 
   protected <K, V> Map<K, V> create() {
     TestMap<K, V> inner = new TestMap<>(new HashMap<K, V>(), mutex);

guava-tests/test/com/google/common/collect/SynchronizedMultimapTest.java

@@ -75,7 +75,7 @@ protected SetMultimap<String, String> create(Entry<String, String>[] entries) {
   private static final class TestMultimap<K, V> extends ForwardingSetMultimap<K, V>
       implements Serializable {
     final SetMultimap<K, V> delegate = HashMultimap.create();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     protected SetMultimap<K, V> delegate() {

guava-tests/test/com/google/common/collect/SynchronizedSetTest.java

@@ -40,7 +40,7 @@
  */
 public class SynchronizedSetTest extends TestCase {
 
-  public static final Object MUTEX = new Integer(1); // something Serializable
+  public static final Object MUTEX = new XplatMonitor(); // something Serializable
 
   public static Test suite() {
     return SetTestSuiteBuilder.using(

guava-tests/test/com/google/common/collect/SynchronizedTableTest.java

@@ -25,7 +25,7 @@
 public class SynchronizedTableTest extends AbstractTableTest<Character> {
   private static final class TestTable<R, C, V> implements Table<R, C, V>, Serializable {
     final Table<R, C, V> delegate = HashBasedTable.create();
-    public final Object mutex = new Integer(1); // something Serializable
+    public final Object mutex = new XplatMonitor(); // something Serializable
 
     @Override
     public String toString() {

guava-tests/test/com/google/common/util/concurrent/FutureCallbackTest.java

@@ -62,7 +62,7 @@ public void testCancel() {
     SettableFuture<String> f = SettableFuture.create();
     FutureCallback<String> callback =
         new FutureCallback<String>() {
-          private final Object monitor = new Object();
+          private final XplatMonitor monitor = new XplatMonitor();
           private boolean called = false;
 
           @Override
@@ -183,7 +183,7 @@ private final class MockCallback implements FutureCallback<String> {
     @Nullable private String value = null;
     @Nullable private Throwable failure = null;
     private boolean wasCalled = false;
-    private final Object monitor = new Object();
+    private final XplatMonitor monitor = new XplatMonitor();
 
     MockCallback(String expectedValue) {
       this.value = expectedValue;

guava/src/com/google/common/base/Suppliers.java

@@ -120,8 +120,7 @@ public String toString() {
 
   @VisibleForTesting
   static class MemoizingSupplier<T extends @Nullable Object> implements Supplier<T>, Serializable {
-    private final Object lock =
-        new Integer(1); // something serializable
+    private final XplatMonitor lock = new XplatMonitor();
 
     final Supplier<T> delegate;
     transient volatile boolean initialized;
@@ -163,7 +162,7 @@ public String toString() {
 
   @VisibleForTesting
   static class NonSerializableMemoizingSupplier<T extends @Nullable Object> implements Supplier<T> {
-    private final Object lock = new Object();
+    private final XplatMonitor lock = new XplatMonitor();
 
     @SuppressWarnings("UnnecessaryLambda") // Must be a fixed singleton object
     private static final Supplier<Void> SUCCESSFULLY_COMPUTED =
@@ -275,8 +274,7 @@ public String toString() {
   @SuppressWarnings("GoodTime") // lots of violations
   static class ExpiringMemoizingSupplier<T extends @Nullable Object>
       implements Supplier<T>, Serializable {
-    private final Object lock =
-        new Integer(1); // something serializable
+    private final XplatMonitor lock = new XplatMonitor();
 
     final Supplier<T> delegate;
     final long durationNanos;

guava/src/com/google/common/base/XplatMonitor.java

@@ -0,0 +1,15 @@
+package com.google.common.base;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * Using this class instead of Object will allow J2kt to substitute monitors in a way that works for
+ * Kotlin native. This class is marked as Serializable so it can be "just" included in serializable
+ * classes despite this not making much sense.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

guava/src/com/google/common/collect/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.collect;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

guava/src/com/google/common/io/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.io;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}

guava/src/com/google/common/util/concurrent/DirectExecutorService.java

@@ -29,7 +29,7 @@
 final class DirectExecutorService extends AbstractListeningExecutorService {
 
   /** Lock used whenever accessing the state variables (runningTasks, shutdown) of the executor */
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   /*
    * Conceptually, these two variables describe the executor being in

guava/src/com/google/common/util/concurrent/LazyLogger.java

@@ -22,7 +22,7 @@
 @GwtCompatible
 @ElementTypesAreNonnullByDefault
 final class LazyLogger {
-  private final Object lock = new Object();
+  private final XplatMonitor lock = new XplatMonitor();
 
   private final String loggerName;
   private volatile @Nullable Logger logger;

guava/src/com/google/common/util/concurrent/XplatMonitor.java

@@ -0,0 +1,13 @@
+package com.google.common.util.concurrent;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.errorprone.annotations.ThreadSafe;
+import java.io.Serializable;
+
+/**
+ * One of our per-package copies of {@link com.google.common.base.XplatMonitor}.
+ */
+@GwtCompatible
+@ThreadSafe
+@ElementTypesAreNonnullByDefault
+final class XplatMonitor implements Serializable {}