src/share/classes/java/util/stream/BaseStream.java

rev 7982 : 8017513: Support for closeable streams
8022237: j.u.s.BaseStream.onClose() has an issue in implementation or requires spec clarification
8022572: Same exception instances thrown from j.u.stream.Stream.onClose() handlers are not listed as suppressed
Summary: BaseStream implements AutoCloseable; Remove CloseableStream and DelegatingStream
Reviewed-by: alanb, mduigou, psandoz
Contributed-by: brian.goetz@oracle.com

*** 33,43 ****
   *
   * @param <T> type of stream elements
   * @param <S> type of stream implementing {@code BaseStream}
   * @since 1.8
   */
! public interface BaseStream<T, S extends BaseStream<T, S>> {
      /**
       * Returns an iterator for the elements of this stream.
       *
       * <p>This is a <a href="package-summary.html#StreamOps">terminal
       * operation</a>.
--- 33,44 ----
   *
   * @param <T> type of stream elements
   * @param <S> type of stream implementing {@code BaseStream}
   * @since 1.8
   */
! public interface BaseStream<T, S extends BaseStream<T, S>>
!         extends AutoCloseable {
      /**
       * Returns an iterator for the elements of this stream.
       *
       * <p>This is a <a href="package-summary.html#StreamOps">terminal
       * operation</a>.
*** 101,106 ****
--- 102,136 ----
       * operation</a>.
       *
       * @return an unordered stream
       */
      S unordered();
+ 
+     /**
+      * Returns an equivalent stream with an additional close handler.  Close
+      * handlers are run when the {@link #close()} method
+      * is called on the stream, and are executed in the order they were
+      * added.  All close handlers are run, even if earlier close handlers throw
+      * exceptions.  If any close handler throws an exception, the first
+      * exception thrown will be relayed to the caller of {@code close()}, with
+      * any remaining exceptions added to that exception as suppressed exceptions
+      * (unless one of the remaining exceptions is the same exception as the
+      * first exception, since an exception cannot suppress itself.)  May
+      * return itself.
+      *
+      * <p>This is an <a href="package-summary.html#StreamOps">intermediate
+      * operation</a>.
+      *
+      * @param closeHandler A task to execute when the stream is closed
+      * @return a stream with a handler that is run if the stream is closed
+      */
+     S onClose(Runnable closeHandler);
+ 
+     /**
+      * Closes this stream, causing all close handlers for this stream pipeline
+      * to be called.
+      *
+      * @see AutoCloseable#close()
+      */
+     @Override
+     void close();
  }