程序包 java.util.function

接口 DoubleUnaryOperator

函数接口:

这是一个函数接口, 因此可用作 lambda 表达式或方法引用的赋值目标。

@FunctionalInterface
public interface DoubleUnaryOperator

Represents an operation on a single double-valued operand that produces a double-valued result. This is the primitive type specialization of UnaryOperator for double.

This is a functional interface whose functional method is applyAsDouble(double).

从以下版本开始:

1.8

另请参阅:

UnaryOperator

方法概要

限定符和类型	方法	说明
default DoubleUnaryOperator	andThen(DoubleUnaryOperator after)	Returns a composed operator that first applies this operator to its input, and then applies the after operator to the result.
double	applyAsDouble(double operand)	Applies this operator to the given operand.
default DoubleUnaryOperator	compose(DoubleUnaryOperator before)	Returns a composed operator that first applies the before operator to its input, and then applies this operator to the result.
static DoubleUnaryOperator	identity()	Returns a unary operator that always returns its input argument.

方法详细资料

applyAsDouble

double applyAsDouble(double operand)

Applies this operator to the given operand.

参数:

operand - the operand

返回:

the operator result

compose

default DoubleUnaryOperator compose(DoubleUnaryOperator before)

Returns a composed operator that first applies the before operator to its input, and then applies this operator to the result. If evaluation of either operator throws an exception, it is relayed to the caller of the composed operator.

参数:

before - the operator to apply before this operator is applied

返回:

a composed operator that first applies the before operator and then applies this operator

抛出:

NullPointerException - if before is null

另请参阅:

andThen(DoubleUnaryOperator)

andThen

default DoubleUnaryOperator andThen(DoubleUnaryOperator after)

Returns a composed operator that first applies this operator to its input, and then applies the after operator to the result. If evaluation of either operator throws an exception, it is relayed to the caller of the composed operator.

参数:

after - the operator to apply after this operator is applied

返回:

a composed operator that first applies this operator and then applies the after operator

抛出:

NullPointerException - if after is null

另请参阅:

compose(DoubleUnaryOperator)

identity

static DoubleUnaryOperator identity()

Returns a unary operator that always returns its input argument.

返回:

a unary operator that always returns its input argument