/*
* 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);
}
/**
/**代码未完, 请加载全部代码(NowJava.com).**/