--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/java/util/stream/TerminalOp.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package java.util.stream;
+
+import java.util.Spliterator;
+
+/**
+ * An operation in a stream pipeline that takes a stream as input and produces
+ * a result or side-effect.  A {@code TerminalOp} has an input type and stream
+ * shape, and a result type.  A {@code TerminalOp} also has a set of
+ * <em>operation flags</em> that describes how the operation processes elements
+ * of the stream (such as short-circuiting or respecting encounter order; see
+ * {@link StreamOpFlag}).
+ *
+ * <p>A {@code TerminalOp} must provide a sequential and parallel implementation
+ * of the operation relative to a given stream source and set of intermediate
+ * operations.
+ *
+ * @param <E_IN> the type of input elements
+ * @param <R>    the type of the result
+ * @since 1.8
+ */
+interface TerminalOp<E_IN, R> {
+    /**
+     * Gets the shape of the input type of this operation.
+     *
+     * @implSpec The default returns {@code StreamShape.REFERENCE}.
+     *
+     * @return StreamShape of the input type of this operation
+     */
+    default StreamShape inputShape() { return StreamShape.REFERENCE; }
+
+    /**
+     * Gets the stream flags of the operation.  Terminal operations may set a
+     * limited subset of the stream flags defined in {@link StreamOpFlag}, and
+     * these flags are combined with the previously combined stream and
+     * intermediate operation flags for the pipeline.
+     *
+     * @implSpec The default implementation returns zero.
+     *
+     * @return the stream flags for this operation
+     * @see StreamOpFlag
+     */
+    default int getOpFlags() { return 0; }
+
+    /**
+     * Performs a parallel evaluation of the operation using the specified
+     * {@code PipelineHelper}, which describes the upstream intermediate
+     * operations.
+     *
+     * @implSpec The default performs a sequential evaluation of the operation
+     * using the specified {@code PipelineHelper}.
+     *
+     * @param helper the pipeline helper
+     * @param spliterator the source spliterator
+     * @return the result of the evaluation
+     */
+    default <P_IN> R evaluateParallel(PipelineHelper<E_IN> helper,
+                                      Spliterator<P_IN> spliterator) {
+        if (Tripwire.ENABLED)
+            Tripwire.trip(getClass(), "{0} triggering TerminalOp.evaluateParallel serial default");
+        return evaluateSequential(helper, spliterator);
+    }
+
+    /**
+     * Performs a sequential evaluation of the operation using the specified
+     * {@code PipelineHelper}, which describes the upstream intermediate
+     * operations.
+     *
+     * @param helper the pipeline helper
+     * @param spliterator the source spliterator
+     * @return the result of the evaluation
+     */
+    <P_IN> R evaluateSequential(PipelineHelper<E_IN> helper,
+                                Spliterator<P_IN> spliterator);
+}