96 lines
3.6 KiB
Java
96 lines
3.6 KiB
Java
/*
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* Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.util.function;
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import java.util.Objects;
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/**
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* Represents an operation on a single {@code double}-valued operand that produces
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* a {@code double}-valued result. This is the primitive type specialization of
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* {@link UnaryOperator} for {@code double}.
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*
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* <p>This is a <a href="package-summary.html">functional interface</a>
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* whose functional method is {@link #applyAsDouble(double)}.
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*
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* @see UnaryOperator
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* @since 1.8
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*/
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@FunctionalInterface
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public interface DoubleUnaryOperator {
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/**
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* Applies this operator to the given operand.
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*
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* @param operand the operand
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* @return the operator result
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*/
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double applyAsDouble(double operand);
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/**
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* Returns a composed operator that first applies the {@code before}
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* operator to its input, and then applies this operator to the result.
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* If evaluation of either operator throws an exception, it is relayed to
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* the caller of the composed operator.
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*
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* @param before the operator to apply before this operator is applied
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* @return a composed operator that first applies the {@code before}
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* operator and then applies this operator
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* @throws NullPointerException if before is null
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*
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* @see #andThen(DoubleUnaryOperator)
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*/
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default DoubleUnaryOperator compose(DoubleUnaryOperator before) {
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Objects.requireNonNull(before);
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return (double v) -> applyAsDouble(before.applyAsDouble(v));
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}
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/**
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* Returns a composed operator that first applies this operator to
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* its input, and then applies the {@code after} operator to the result.
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* If evaluation of either operator throws an exception, it is relayed to
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* the caller of the composed operator.
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*
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* @param after the operator to apply after this operator is applied
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* @return a composed operator that first applies this operator and then
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* applies the {@code after} operator
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* @throws NullPointerException if after is null
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*
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* @see #compose(DoubleUnaryOperator)
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*/
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default DoubleUnaryOperator andThen(DoubleUnaryOperator after) {
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Objects.requireNonNull(after);
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return (double t) -> after.applyAsDouble(applyAsDouble(t));
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}
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/**
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* Returns a unary operator that always returns its input argument.
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*
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* @return a unary operator that always returns its input argument
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*/
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static DoubleUnaryOperator identity() {
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return t -> t;
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}
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}
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