add TtlEnhanced tag interface

src/main/java/com/alibaba/ttl/TtlCallable.java

@@ -28,7 +28,7 @@ import static com.alibaba.ttl.TransmittableThreadLocal.Transmitter.*;
  * @see java.util.concurrent.ExecutorCompletionService
  * @since 0.9.0
  */
-public final class TtlCallable<V> implements Callable<V> {
+public final class TtlCallable<V> implements Callable<V>, TtlEnhanced {
     private final AtomicReference<Object> capturedRef;
     private final Callable<V> callable;
     private final boolean releaseTtlValueReferenceAfterCall;
@@ -123,7 +123,7 @@ public final class TtlCallable<V> implements Callable<V> {
     public static <T> TtlCallable<T> get(@Nullable Callable<T> callable, boolean releaseTtlValueReferenceAfterCall, boolean idempotent) {
         if (null == callable) return null;
 
-        if (callable instanceof TtlCallable) {
+        if (callable instanceof TtlEnhanced) {
             // avoid redundant decoration, and ensure idempotency
             if (idempotent) return (TtlCallable<T>) callable;
             else throw new IllegalStateException("Already TtlCallable!");

src/main/java/com/alibaba/ttl/TtlEnhanced.java

+package com.alibaba.ttl;
+
+/**
+ * a Ttl marker/tag interface, for ttl enhanced class, for example {@code TTL wrapper}.
+ */
+public interface TtlEnhanced {
+}

src/main/java/com/alibaba/ttl/TtlRecursiveAction.java

@@ -11,7 +11,7 @@ import static com.alibaba.ttl.TransmittableThreadLocal.Transmitter.*;
  * @see java.util.concurrent.RecursiveAction
  * @since 2.4.0
  */
-public abstract class TtlRecursiveAction extends ForkJoinTask<Void> {
+public abstract class TtlRecursiveAction extends ForkJoinTask<Void> implements TtlEnhanced {
 
     private static final long serialVersionUID = -5753568484583412377L;
 

src/main/java/com/alibaba/ttl/TtlRecursiveTask.java

@@ -11,7 +11,7 @@ import static com.alibaba.ttl.TransmittableThreadLocal.Transmitter.*;
  * @see java.util.concurrent.RecursiveTask
  * @since 2.4.0
  */
-public abstract class TtlRecursiveTask<V> extends ForkJoinTask<V> {
+public abstract class TtlRecursiveTask<V> extends ForkJoinTask<V> implements TtlEnhanced {
 
     private static final long serialVersionUID = 1814679366926362436L;
 

src/main/java/com/alibaba/ttl/TtlRunnable.java

@@ -25,7 +25,7 @@ import static com.alibaba.ttl.TransmittableThreadLocal.Transmitter.*;
  * @see java.util.concurrent.Executors
  * @since 0.9.0
  */
-public final class TtlRunnable implements Runnable {
+public final class TtlRunnable implements Runnable, TtlEnhanced {
     private final AtomicReference<Object> capturedRef;
     private final Runnable runnable;
     private final boolean releaseTtlValueReferenceAfterRun;
@@ -122,7 +122,7 @@ public final class TtlRunnable implements Runnable {
     public static TtlRunnable get(@Nullable Runnable runnable, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
         if (null == runnable) return null;
 
-        if (runnable instanceof TtlRunnable) {
+        if (runnable instanceof TtlEnhanced) {
             // avoid redundant decoration, and ensure idempotency
             if (idempotent) return (TtlRunnable) runnable;
             else throw new IllegalStateException("Already TtlRunnable!");

src/main/java/com/alibaba/ttl/TtlTimerTask.java

@@ -25,7 +25,7 @@ import static com.alibaba.ttl.TransmittableThreadLocal.Transmitter.*;
  * @deprecated Use {@link TtlRunnable}, {@link java.util.concurrent.ScheduledExecutorService} instead of {@link java.util.Timer}, {@link java.util.TimerTask}.
  */
 @Deprecated
-public final class TtlTimerTask extends TimerTask {
+public final class TtlTimerTask extends TimerTask implements TtlEnhanced {
     private final AtomicReference<Object> capturedRef;
     private final TimerTask timerTask;
     private final boolean releaseTtlValueReferenceAfterRun;
@@ -121,7 +121,7 @@ public final class TtlTimerTask extends TimerTask {
     public static TtlTimerTask get(@Nullable TimerTask timerTask, boolean releaseTtlValueReferenceAfterRun, boolean idempotent) {
         if (null == timerTask) return null;
 
-        if (timerTask instanceof TtlTimerTask) {
+        if (timerTask instanceof TtlEnhanced) {
             // avoid redundant decoration, and ensure idempotency
             if (idempotent) return (TtlTimerTask) timerTask;
             else throw new IllegalStateException("Already TtlTimerTask!");

src/main/java/com/alibaba/ttl/threadpool/ExecutorServiceTtlWrapper.java

@@ -2,6 +2,7 @@ package com.alibaba.ttl.threadpool;
 
 import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlCallable;
+import com.alibaba.ttl.TtlEnhanced;
 import com.alibaba.ttl.TtlRunnable;
 
 import javax.annotation.Nonnull;
@@ -17,7 +18,7 @@ import java.util.concurrent.*;
  * @author Jerry Lee (oldratlee at gmail dot com)
  * @since 0.9.0
  */
-class ExecutorServiceTtlWrapper extends ExecutorTtlWrapper implements ExecutorService {
+class ExecutorServiceTtlWrapper extends ExecutorTtlWrapper implements ExecutorService, TtlEnhanced {
     private final ExecutorService executorService;
 
     ExecutorServiceTtlWrapper(@Nonnull ExecutorService executorService) {

src/main/java/com/alibaba/ttl/threadpool/ExecutorTtlWrapper.java

@@ -2,6 +2,7 @@ package com.alibaba.ttl.threadpool;
 
 import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlRunnable;
+import com.alibaba.ttl.TtlEnhanced;
 
 import javax.annotation.Nonnull;
 import java.util.concurrent.Executor;
@@ -14,7 +15,7 @@ import java.util.concurrent.Executor;
  * @author Jerry Lee (oldratlee at gmail dot com)
  * @since 0.9.0
  */
-class ExecutorTtlWrapper implements Executor {
+class ExecutorTtlWrapper implements Executor, TtlEnhanced {
     private final Executor executor;
 
     ExecutorTtlWrapper(@Nonnull Executor executor) {

src/main/java/com/alibaba/ttl/threadpool/ScheduledExecutorServiceTtlWrapper.java

@@ -2,6 +2,7 @@ package com.alibaba.ttl.threadpool;
 
 import com.alibaba.ttl.TransmittableThreadLocal;
 import com.alibaba.ttl.TtlCallable;
+import com.alibaba.ttl.TtlEnhanced;
 import com.alibaba.ttl.TtlRunnable;
 
 import javax.annotation.Nonnull;
@@ -15,7 +16,7 @@ import java.util.concurrent.*;
  * @author Jerry Lee (oldratlee at gmail dot com)
  * @since 0.9.0
  */
-class ScheduledExecutorServiceTtlWrapper extends ExecutorServiceTtlWrapper implements ScheduledExecutorService {
+class ScheduledExecutorServiceTtlWrapper extends ExecutorServiceTtlWrapper implements ScheduledExecutorService, TtlEnhanced {
     final ScheduledExecutorService scheduledExecutorService;
 
     public ScheduledExecutorServiceTtlWrapper(@Nonnull ScheduledExecutorService scheduledExecutorService) {

src/main/java/com/alibaba/ttl/threadpool/TtlExecutors.java

 package com.alibaba.ttl.threadpool;
 
 import com.alibaba.ttl.TransmittableThreadLocal;
+import com.alibaba.ttl.TtlEnhanced;
 import com.alibaba.ttl.threadpool.agent.TtlAgent;
 
 import javax.annotation.Nullable;
@@ -34,7 +35,7 @@ public final class TtlExecutors {
      */
     @Nullable
     public static Executor getTtlExecutor(@Nullable Executor executor) {
-        if (TtlAgent.isTtlAgentLoaded() || null == executor || executor instanceof ExecutorTtlWrapper) {
+        if (TtlAgent.isTtlAgentLoaded() || null == executor || executor instanceof TtlEnhanced) {
             return executor;
         }
         return new ExecutorTtlWrapper(executor);
@@ -47,7 +48,7 @@ public final class TtlExecutors {
      */
     @Nullable
     public static ExecutorService getTtlExecutorService(@Nullable ExecutorService executorService) {
-        if (TtlAgent.isTtlAgentLoaded() || executorService == null || executorService instanceof ExecutorServiceTtlWrapper) {
+        if (TtlAgent.isTtlAgentLoaded() || executorService == null || executorService instanceof TtlEnhanced) {
             return executorService;
         }
         return new ExecutorServiceTtlWrapper(executorService);
@@ -60,7 +61,7 @@ public final class TtlExecutors {
      */
     @Nullable
     public static ScheduledExecutorService getTtlScheduledExecutorService(@Nullable ScheduledExecutorService scheduledExecutorService) {
-        if (TtlAgent.isTtlAgentLoaded() || scheduledExecutorService == null || scheduledExecutorService instanceof ScheduledExecutorServiceTtlWrapper) {
+        if (TtlAgent.isTtlAgentLoaded() || scheduledExecutorService == null || scheduledExecutorService instanceof TtlEnhanced) {
             return scheduledExecutorService;
         }
         return new ScheduledExecutorServiceTtlWrapper(scheduledExecutorService);
@@ -82,7 +83,7 @@ public final class TtlExecutors {
      * @since 2.8.0
      */
     public static <T extends Executor> boolean isTtlWrapper(@Nullable T executor) {
-        return executor instanceof ExecutorTtlWrapper;
+        return executor instanceof TtlEnhanced;
     }
 
     /**