import java.util.Collections;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.Executor;
import java.util.logging.Level;

/**
 * A list of listeners for implementing a concurrency friendly observable object.
 *
 * <p>Listeners are registered once via {@link #addListener} and then may be invoked by {@linkplain
 * #enqueue enqueueing} and then {@linkplain #dispatch dispatching} events.
 *

   * expected</i>, but not absolutely required, to have the following properties:
   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code Objects.equal(function.apply(a),
   *       function.apply(b))}.

   * class documentation above). This method is <i>generally expected</i>, but not absolutely
   * required, to have the following properties:
   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.

   * class documentation above). This method is <i>generally expected</i>, but not absolutely
   * required, to have the following properties:
   *
   * <ul>
   *   <li>Its execution does not cause any observable side effects.
   *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
   *       Objects.equal}{@code (a, b)} implies that {@code predicate.apply(a) ==
   *       predicate.apply(b))}.

   * processing and may run concurrently, for example, if the JVM flag {@code
   * -XX:+ExplicitGCInvokesConcurrent} is used.
   *
   * <p>Whenever possible, it is preferable to test directly for some observable change resulting
   * from GC, as with {@link #awaitClear}. Because there are no guarantees for the order of GC
   * finalization processing, there may still be some unfinished work for the GC to do after this

   * processing and may run concurrently, for example, if the JVM flag {@code
   * -XX:+ExplicitGCInvokesConcurrent} is used.
   *
   * <p>Whenever possible, it is preferable to test directly for some observable change resulting
   * from GC, as with {@link #awaitClear}. Because there are no guarantees for the order of GC
   * finalization processing, there may still be some unfinished work for the GC to do after this

        .contains("Exception thrown from implementation: class java.lang.StackOverflowError");
  }

  // Regression test for a case where we would fail to execute listeners immediately on done futures
  // this would be observable from an afterDone callback
  public void testListenersExecuteImmediately_fromAfterDone() {
    AbstractFuture<String> f =
        new AbstractFuture<String>() {
          @Override

        .contains("Exception thrown from implementation: class java.lang.StackOverflowError");
  }

  // Regression test for a case where we would fail to execute listeners immediately on done futures
  // this would be observable from an afterDone callback
  public void testListenersExecuteImmediately_fromAfterDone() {
    AbstractFuture<String> f =
        new AbstractFuture<String>() {
          @Override

     * expected</i>, but not absolutely required, to have the following properties:
     *
     * <ul>
     *   <li>Its execution does not cause any observable side effects.
     *   <li>The computation is <i>consistent with equals</i>; that is, {@link Objects#equal
     *       Objects.equal}{@code (k1, k2) &&} {@link Objects#equal}{@code (v1, v2)} implies that

// Submitted by Piotr Zduniak <******@****.***>
pcloud.host

// NYC.mn : http://www.information.nyc.mn
// Submitted by Matthew Brown <******@****.***>
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// Observable, Inc. : https://observablehq.com
// Submitted by Mike Bostock <******@****.***>
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// Octopodal Solutions, LLC. : https://ulterius.io/