TimeModifier.java

/*
 * Copyright 2016 MovingBlocks
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.terasology.rendering.animation;

import java.util.Objects;

/**
 * Applies a functional transformation to a given float value.
 */
public interface TimeModifier {
    /**
     * Modifies a given (temporal) value
     * @param value a value in the range [0..1]
     * @return a value in the range [0..1]
     */
    float apply(float value);

    /**
     * Returns a composed function that first applies this function to
     * its input, and then applies the {@code after} function to the result.
     * If evaluation of either function throws an exception, it is relayed to
     * the caller of the composed function.
     *
     * @param after the function to apply after this function is applied
     * @return a composed function that first applies this function and then
     * applies the {@code after} function
     * @throws NullPointerException if after is null
     */
    default TimeModifier andThen(TimeModifier after) {
        Objects.requireNonNull(after);
        return (t) -> after.apply(apply(t));
    }
}