Java 类com.google.common.base.FinalizablePhantomReference 实例源码

private JobData newJobDataReference(final JobData delegate) {
  final JobData result = new JobDataWrapper(delegate);
  FinalizableReference ref = new FinalizablePhantomReference<JobData>(result, FINALIZABLE_REFERENCE_QUEUE) {
    @Override
    public void finalizeReferent() {
      jobResultReferences.remove(this);
      try {
        delegate.close();
      } catch (Exception e) {
        logger.warn(String.format("Failed to close the data object for job %s", delegate.getJobId()), e);
      }
    }
  };

  jobResultReferences.add(ref);

  return result;
}

@Override
protected void offer(final T source) {
    final T present = cache.getIfPresent(source.getIdentifier());
    if (present == null) {
        cache.put(source.getIdentifier(), source);

        final SchemaSourceRegistration<T> reg = register(source.getIdentifier());
        final FinalizablePhantomReference<T> ref = new FinalizablePhantomReference<T>(source, queue) {
            @Override
            public void finalizeReferent() {
                reg.close();
                regs.remove(this);
            }
        };

        regs.add(ref);
    }
}

@Override
public void close() {
    while (!regs.isEmpty()) {
        final FinalizablePhantomReference<?> ref = regs.get(0);
        ref.finalizeReferent();
    }

    cache.invalidateAll();
    queue.close();
}