https://www.graalvm.org/ 
final class com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler
  minor version: 0
  major version: 59
  flags: flags: (0x0030) ACC_FINAL, ACC_SUPER
  this_class: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler
  super_class: java.lang.Object
{
  private final com.oracle.truffle.api.instrumentation.Instrumenter instrumenter;
    descriptor: Lcom/oracle/truffle/api/instrumentation/Instrumenter;
    flags: (0x0012) ACC_PRIVATE, ACC_FINAL

  private volatile com.oracle.truffle.api.instrumentation.EventBinding<?> cancellationBinding;
    descriptor: Lcom/oracle/truffle/api/instrumentation/EventBinding;
    flags: (0x0042) ACC_PRIVATE, ACC_VOLATILE
    Signature: Lcom/oracle/truffle/api/instrumentation/EventBinding<*>;

  private int cancellationUsers;
    descriptor: I
    flags: (0x0002) ACC_PRIVATE

  final com.oracle.truffle.polyglot.PolyglotEngineImpl this$0;
    descriptor: Lcom/oracle/truffle/polyglot/PolyglotEngineImpl;
    flags: (0x1010) ACC_FINAL, ACC_SYNTHETIC

  void <init>(com.oracle.truffle.polyglot.PolyglotEngineImpl);
    descriptor: (Lcom/oracle/truffle/polyglot/PolyglotEngineImpl;)V
    flags: (0x0000) 
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
         0: .line 1390
            aload 0 /* this */
            aload 1
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.this$0:Lcom/oracle/truffle/polyglot/PolyglotEngineImpl;
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
         1: .line 1391
            aload 0 /* this */
            getstatic com.oracle.truffle.polyglot.EngineAccessor.INSTRUMENT:Lcom/oracle/truffle/api/impl/Accessor$InstrumentSupport;
            aload 1
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl.instrumentationHandler:Ljava/lang/Object;
            invokevirtual com.oracle.truffle.api.impl.Accessor$InstrumentSupport.getEngineInstrumenter:(Ljava/lang/Object;)Ljava/lang/Object;
            checkcast com.oracle.truffle.api.instrumentation.Instrumenter
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.instrumenter:Lcom/oracle/truffle/api/instrumentation/Instrumenter;
         2: .line 1392
            return
        end local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0  this  Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;
    MethodParameters:
        Name  Flags
      this$0  final

  void cancel(java.util.List<com.oracle.truffle.polyglot.PolyglotContextImpl>);
    descriptor: (Ljava/util/List;)V
    flags: (0x0000) 
    Code:
      stack=5, locals=2, args_size=2
        start local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
        start local 1 // java.util.List localContexts
         0: .line 1395
            aload 0 /* this */
            aload 1 /* localContexts */
            lconst_0
            aconst_null
            invokevirtual com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancel:(Ljava/util/List;JLjava/time/Duration;)Z
            pop
         1: .line 1396
            return
        end local 1 // java.util.List localContexts
        end local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
      LocalVariableTable:
        Start  End  Slot           Name  Signature
            0    2     0           this  Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;
            0    2     1  localContexts  Ljava/util/List<Lcom/oracle/truffle/polyglot/PolyglotContextImpl;>;
    Signature: (Ljava/util/List<Lcom/oracle/truffle/polyglot/PolyglotContextImpl;>;)V
    MethodParameters:
               Name  Flags
      localContexts  

  boolean cancel(java.util.List<com.oracle.truffle.polyglot.PolyglotContextImpl>, long, java.time.Duration);
    descriptor: (Ljava/util/List;JLjava/time/Duration;)Z
    flags: (0x0000) 
    Code:
      stack=5, locals=13, args_size=4
        start local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
        start local 1 // java.util.List localContexts
        start local 2 // long startMillis
        start local 4 // java.time.Duration timeout
         0: .line 1399
            iconst_0
            istore 5 /* cancelling */
        start local 5 // boolean cancelling
         1: .line 1400
            aload 1 /* localContexts */
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 7
            goto 6
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int top java.util.Iterator
      StackMap stack:
         2: aload 7
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast com.oracle.truffle.polyglot.PolyglotContextImpl
            astore 6 /* context */
        start local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
         3: .line 1401
            aload 6 /* context */
            getfield com.oracle.truffle.polyglot.PolyglotContextImpl.cancelling:Z
            ifne 4
            aload 6 /* context */
            getfield com.oracle.truffle.polyglot.PolyglotContextImpl.interrupting:Z
            ifeq 6
         4: .line 1402
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int com.oracle.truffle.polyglot.PolyglotContextImpl java.util.Iterator
      StackMap stack:
            iconst_1
            istore 5 /* cancelling */
         5: .line 1403
            goto 7
        end local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
         6: .line 1400
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int top java.util.Iterator
      StackMap stack:
            aload 7
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 2
         7: .line 1406
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int
      StackMap stack:
            iload 5 /* cancelling */
            ifeq 35
         8: .line 1407
            aload 0 /* this */
            invokevirtual com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.enableCancel:()V
         9: .line 1409
            aload 1 /* localContexts */
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 7
            goto 12
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int top java.util.Iterator
      StackMap stack:
        10: aload 7
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast com.oracle.truffle.polyglot.PolyglotContextImpl
            astore 6 /* context */
        start local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        11: .line 1410
            aload 6 /* context */
            invokevirtual com.oracle.truffle.polyglot.PolyglotContextImpl.sendInterrupt:()V
        end local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        12: .line 1409
      StackMap locals:
      StackMap stack:
            aload 7
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 10
        13: .line 1412
            aload 4 /* timeout */
            ifnonnull 19
        14: .line 1413
            aload 1 /* localContexts */
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 7
            goto 17
      StackMap locals:
      StackMap stack:
        15: aload 7
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast com.oracle.truffle.polyglot.PolyglotContextImpl
            astore 6 /* context */
        start local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        16: .line 1414
            aload 6 /* context */
            invokevirtual com.oracle.truffle.polyglot.PolyglotContextImpl.waitForClose:()V
        end local 6 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        17: .line 1413
      StackMap locals:
      StackMap stack:
            aload 7
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 15
        18: .line 1416
            goto 34
        19: .line 1417
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int
      StackMap stack:
            aload 4 /* timeout */
            getstatic java.time.Duration.ZERO:Ljava/time/Duration;
            if_acmpeq 20
            aload 4 /* timeout */
            invokevirtual java.time.Duration.toMillis:()J
            goto 21
      StackMap locals:
      StackMap stack:
        20: lconst_0
      StackMap locals:
      StackMap stack: long
        21: lstore 6 /* cancelTimeoutMillis */
        start local 6 // long cancelTimeoutMillis
        22: .line 1418
            iconst_1
            istore 8 /* success */
        start local 8 // boolean success
        23: .line 1419
            aload 1 /* localContexts */
            invokeinterface java.util.List.iterator:()Ljava/util/Iterator;
            astore 10
            goto 27
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int long int top java.util.Iterator
      StackMap stack:
        24: aload 10
            invokeinterface java.util.Iterator.next:()Ljava/lang/Object;
            checkcast com.oracle.truffle.polyglot.PolyglotContextImpl
            astore 9 /* context */
        start local 9 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        25: .line 1420
            aload 9 /* context */
            lload 2 /* startMillis */
            lload 6 /* cancelTimeoutMillis */
            invokevirtual com.oracle.truffle.polyglot.PolyglotContextImpl.waitForThreads:(JJ)Z
            ifne 27
        26: .line 1421
            iconst_0
            istore 8 /* success */
        end local 9 // com.oracle.truffle.polyglot.PolyglotContextImpl context
        27: .line 1419
      StackMap locals:
      StackMap stack:
            aload 10
            invokeinterface java.util.Iterator.hasNext:()Z
            ifne 24
        28: .line 1424
            iload 8 /* success */
            istore 12
        29: .line 1427
            aload 0 /* this */
            invokevirtual com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.disableCancel:()V
        30: .line 1424
            iload 12
            ireturn
        end local 8 // boolean success
        end local 6 // long cancelTimeoutMillis
        31: .line 1426
      StackMap locals: com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler java.util.List long java.time.Duration int
      StackMap stack: java.lang.Throwable
            astore 11
        32: .line 1427
            aload 0 /* this */
            invokevirtual com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.disableCancel:()V
        33: .line 1428
            aload 11
            athrow
        34: .line 1427
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            invokevirtual com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.disableCancel:()V
        35: .line 1430
      StackMap locals:
      StackMap stack:
            iconst_1
            ireturn
        end local 5 // boolean cancelling
        end local 4 // java.time.Duration timeout
        end local 2 // long startMillis
        end local 1 // java.util.List localContexts
        end local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
      LocalVariableTable:
        Start  End  Slot                 Name  Signature
            0   36     0                 this  Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;
            0   36     1        localContexts  Ljava/util/List<Lcom/oracle/truffle/polyglot/PolyglotContextImpl;>;
            0   36     2          startMillis  J
            0   36     4              timeout  Ljava/time/Duration;
            1   36     5           cancelling  Z
            3    6     6              context  Lcom/oracle/truffle/polyglot/PolyglotContextImpl;
           11   12     6              context  Lcom/oracle/truffle/polyglot/PolyglotContextImpl;
           16   17     6              context  Lcom/oracle/truffle/polyglot/PolyglotContextImpl;
           22   31     6  cancelTimeoutMillis  J
           23   31     8              success  Z
           25   27     9              context  Lcom/oracle/truffle/polyglot/PolyglotContextImpl;
      Exception table:
        from    to  target  type
           9    29      31  any
    Signature: (Ljava/util/List<Lcom/oracle/truffle/polyglot/PolyglotContextImpl;>;JLjava/time/Duration;)Z
    MethodParameters:
               Name  Flags
      localContexts  
      startMillis    
      timeout        

  void enableCancel();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=6, locals=2, args_size=1
        start local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
         0: .line 1434
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.this$0:Lcom/oracle/truffle/polyglot/PolyglotEngineImpl;
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl.lock:Ljava/lang/Object;
            dup
            astore 1
            monitorenter
         1: .line 1435
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationBinding:Lcom/oracle/truffle/api/instrumentation/EventBinding;
            ifnonnull 3
         2: .line 1436
            aload 0 /* this */
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.instrumenter:Lcom/oracle/truffle/api/instrumentation/Instrumenter;
            getstatic com.oracle.truffle.api.instrumentation.SourceSectionFilter.ANY:Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter;
            new com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler$1
            dup
            aload 0 /* this */
            invokespecial com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler$1.<init>:(Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;)V
            invokevirtual com.oracle.truffle.api.instrumentation.Instrumenter.attachExecutionEventListener:(Lcom/oracle/truffle/api/instrumentation/SourceSectionFilter;Lcom/oracle/truffle/api/instrumentation/ExecutionEventListener;)Lcom/oracle/truffle/api/instrumentation/EventBinding;
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationBinding:Lcom/oracle/truffle/api/instrumentation/EventBinding;
         3: .line 1462
      StackMap locals: java.lang.Object
      StackMap stack:
            aload 0 /* this */
            dup
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationUsers:I
            iconst_1
            iadd
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationUsers:I
         4: .line 1434
            aload 1
            monitorexit
         5: goto 8
      StackMap locals:
      StackMap stack: java.lang.Throwable
         6: aload 1
            monitorexit
         7: athrow
         8: .line 1464
      StackMap locals:
      StackMap stack:
            return
        end local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    9     0  this  Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;
      Exception table:
        from    to  target  type
           1     5       6  any
           6     7       6  any

  private void disableCancel();
    descriptor: ()V
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=3, locals=4, args_size=1
        start local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
         0: .line 1467
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.this$0:Lcom/oracle/truffle/polyglot/PolyglotEngineImpl;
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl.lock:Ljava/lang/Object;
            dup
            astore 1
            monitorenter
         1: .line 1468
            aload 0 /* this */
            dup
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationUsers:I
            iconst_1
            isub
            dup_x1
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationUsers:I
            istore 2 /* usersLeft */
        start local 2 // int usersLeft
         2: .line 1469
            iload 2 /* usersLeft */
            ifgt 7
         3: .line 1470
            aload 0 /* this */
            getfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationBinding:Lcom/oracle/truffle/api/instrumentation/EventBinding;
            astore 3 /* b */
        start local 3 // com.oracle.truffle.api.instrumentation.EventBinding b
         4: .line 1471
            aload 3 /* b */
            ifnull 6
         5: .line 1472
            aload 3 /* b */
            invokevirtual com.oracle.truffle.api.instrumentation.EventBinding.dispose:()V
         6: .line 1474
      StackMap locals: java.lang.Object int com.oracle.truffle.api.instrumentation.EventBinding
      StackMap stack:
            aload 0 /* this */
            aconst_null
            putfield com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler.cancellationBinding:Lcom/oracle/truffle/api/instrumentation/EventBinding;
        end local 3 // com.oracle.truffle.api.instrumentation.EventBinding b
        end local 2 // int usersLeft
         7: .line 1467
      StackMap locals:
      StackMap stack:
            aload 1
            monitorexit
         8: goto 11
      StackMap locals:
      StackMap stack: java.lang.Throwable
         9: aload 1
            monitorexit
        10: athrow
        11: .line 1477
      StackMap locals:
      StackMap stack:
            return
        end local 0 // com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler this
      LocalVariableTable:
        Start  End  Slot       Name  Signature
            0   12     0       this  Lcom/oracle/truffle/polyglot/PolyglotEngineImpl$CancelHandler;
            2    7     2  usersLeft  I
            4    7     3          b  Lcom/oracle/truffle/api/instrumentation/EventBinding<*>;
      Exception table:
        from    to  target  type
           1     8       9  any
           9    10       9  any
}
SourceFile: "PolyglotEngineImpl.java"
NestHost: com.oracle.truffle.polyglot.PolyglotEngineImpl
InnerClasses:
  public abstract InstrumentSupport = com.oracle.truffle.api.impl.Accessor$InstrumentSupport of com.oracle.truffle.api.impl.Accessor
  final CancelHandler = com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler of com.oracle.truffle.polyglot.PolyglotEngineImpl
  com.oracle.truffle.polyglot.PolyglotEngineImpl$CancelHandler$1