java.util.function.DoubleUnaryOperator Maven / Gradle / Ivy
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package java.util.function;
import java.util.Objects;
/**
* Represents an operation on a single {@code double}-valued operand that produces
* a {@code double}-valued result. This is the primitive type specialization of
* {@link UnaryOperator} for {@code double}.
*
* This is a functional interface
* whose functional method is {@link #applyAsDouble(double)}.
*
* @see UnaryOperator
* @since 1.8
*/
@FunctionalInterface
public interface DoubleUnaryOperator {
/**
* Applies this operator to the given operand.
*
* @param operand the operand
* @return the operator result
*/
double applyAsDouble(double operand);
/**
* Returns a composed operator that first applies the {@code 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.
*
* @param before the operator to apply before this operator is applied
* @return a composed operator that first applies the {@code before}
* operator and then applies this operator
* @throws NullPointerException if before is null
*
* @see #andThen(DoubleUnaryOperator)
*/
default DoubleUnaryOperator compose(DoubleUnaryOperator before) {
Objects.requireNonNull(before);
return (double v) -> applyAsDouble(before.applyAsDouble(v));
}
/**
* Returns a composed operator that first applies this operator to
* its input, and then applies the {@code after} operator to the result.
* If evaluation of either operator throws an exception, it is relayed to
* the caller of the composed operator.
*
* @param after the operator to apply after this operator is applied
* @return a composed operator that first applies this operator and then
* applies the {@code after} operator
* @throws NullPointerException if after is null
*
* @see #compose(DoubleUnaryOperator)
*/
default DoubleUnaryOperator andThen(DoubleUnaryOperator after) {
Objects.requireNonNull(after);
return (double t) -> after.applyAsDouble(applyAsDouble(t));
}
/**
* Returns a unary operator that always returns its input argument.
*
* @return a unary operator that always returns its input argument
*/
static DoubleUnaryOperator identity() {
return t -> t;
}
}