jdk/src/share/classes/java/util/function/ToDoubleFunction.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
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 * 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).
 *
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package java.util.function;

/**
 * Apply a function to the input argument, yielding an appropriate result.
 * This is the {@code double}-bearing specialization for {@link Function}.
 *
 * @param <T> the type of input objects to the function
 *
 * @see Function
 * @since 1.8
 */
@FunctionalInterface
public interface ToDoubleFunction<T> {

    /**
     * Compute the result of applying the function to the input argument
     *
     * @param t the input object
     * @return the function result value
     */
    double applyAsDouble(T t);
}