Java tutorial
/* * Copyright (c) 2016 Gridtec. All rights reserved. * * 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 at.gridtec.lambda4j.function.tri.to; import at.gridtec.lambda4j.Lambda; import at.gridtec.lambda4j.consumer.tri.TriConsumer; import at.gridtec.lambda4j.function.bi.to.ToDoubleBiFunction2; import at.gridtec.lambda4j.function.conversion.DoubleToByteFunction; import at.gridtec.lambda4j.function.conversion.DoubleToCharFunction; import at.gridtec.lambda4j.function.conversion.DoubleToFloatFunction; import at.gridtec.lambda4j.function.conversion.DoubleToShortFunction; import at.gridtec.lambda4j.function.to.ToDoubleFunction2; import at.gridtec.lambda4j.function.tri.TriFunction; import at.gridtec.lambda4j.predicate.tri.TriPredicate; import org.apache.commons.lang3.tuple.Triple; import javax.annotation.Nonnegative; import javax.annotation.Nonnull; import javax.annotation.Nullable; import java.util.Map; import java.util.Objects; import java.util.concurrent.ConcurrentHashMap; import java.util.function.DoubleConsumer; import java.util.function.DoubleFunction; import java.util.function.DoublePredicate; import java.util.function.DoubleToIntFunction; import java.util.function.DoubleToLongFunction; import java.util.function.DoubleUnaryOperator; import java.util.function.Function; import java.util.function.ToDoubleFunction; /** * Represents an operation that accepts three input arguments and produces a * {@code double}-valued result. * This is a primitive specialization of {@link TriFunction}. * <p> * This is a {@link FunctionalInterface} whose functional method is {@link #applyAsDouble(Object, Object, Object)}. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @see TriFunction */ @SuppressWarnings("unused") @FunctionalInterface public interface ToDoubleTriFunction<T, U, V> extends Lambda { /** * Constructs a {@link ToDoubleTriFunction} based on a lambda expression or a method reference. Thereby the given * lambda expression or method reference is returned on an as-is basis to implicitly transform it to the desired * type. With this method, it is possible to ensure that correct type is used from lambda expression or method * reference. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param expression A lambda expression or (typically) a method reference, e.g. {@code this::method} * @return A {@code ToDoubleTriFunction} from given lambda expression or method reference. * @implNote This implementation allows the given argument to be {@code null}, but only if {@code null} given, * {@code null} will be returned. * @see <a href="https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html#syntax">Lambda * Expression</a> * @see <a href="https://docs.oracle.com/javase/tutorial/java/javaOO/methodreferences.html">Method Reference</a> */ static <T, U, V> ToDoubleTriFunction<T, U, V> of(@Nullable final ToDoubleTriFunction<T, U, V> expression) { return expression; } /** * Calls the given {@link ToDoubleTriFunction} with the given arguments and returns its result. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param function The function to be called * @param t The first argument to the function * @param u The second argument to the function * @param v The third argument to the function * @return The result from the given {@code ToDoubleTriFunction}. * @throws NullPointerException If given argument is {@code null} */ static <T, U, V> double call(@Nonnull final ToDoubleTriFunction<? super T, ? super U, ? super V> function, T t, U u, V v) { Objects.requireNonNull(function); return function.applyAsDouble(t, u, v); } /** * Creates a {@link ToDoubleTriFunction} which uses the {@code first} parameter of this one as argument for the * given {@link ToDoubleFunction}. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param function The function which accepts the {@code first} parameter of this one * @return Creates a {@code ToDoubleTriFunction} which uses the {@code first} parameter of this one as argument for * the given {@code ToDoubleFunction}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull static <T, U, V> ToDoubleTriFunction<T, U, V> onlyFirst(@Nonnull final ToDoubleFunction<? super T> function) { Objects.requireNonNull(function); return (t, u, v) -> function.applyAsDouble(t); } /** * Creates a {@link ToDoubleTriFunction} which uses the {@code second} parameter of this one as argument for the * given {@link ToDoubleFunction}. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param function The function which accepts the {@code second} parameter of this one * @return Creates a {@code ToDoubleTriFunction} which uses the {@code second} parameter of this one as argument for * the given {@code ToDoubleFunction}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull static <T, U, V> ToDoubleTriFunction<T, U, V> onlySecond(@Nonnull final ToDoubleFunction<? super U> function) { Objects.requireNonNull(function); return (t, u, v) -> function.applyAsDouble(u); } /** * Creates a {@link ToDoubleTriFunction} which uses the {@code third} parameter of this one as argument for the * given {@link ToDoubleFunction}. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param function The function which accepts the {@code third} parameter of this one * @return Creates a {@code ToDoubleTriFunction} which uses the {@code third} parameter of this one as argument for * the given {@code ToDoubleFunction}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull static <T, U, V> ToDoubleTriFunction<T, U, V> onlyThird(@Nonnull final ToDoubleFunction<? super V> function) { Objects.requireNonNull(function); return (t, u, v) -> function.applyAsDouble(v); } /** * Creates a {@link ToDoubleTriFunction} which always returns a given value. * * @param <T> The type of the first argument to the function * @param <U> The type of the second argument to the function * @param <V> The type of the third argument to the function * @param ret The return value for the constant * @return A {@code ToDoubleTriFunction} which always returns a given value. */ @Nonnull static <T, U, V> ToDoubleTriFunction<T, U, V> constant(double ret) { return (t, u, v) -> ret; } /** * Applies this function to the given arguments. * * @param t The first argument to the function * @param u The second argument to the function * @param v The third argument to the function * @return The return value from the function, which is its result. */ double applyAsDouble(T t, U u, V v); /** * Applies this function to the given tuple. * * @param tuple The tuple to be applied to the function * @return The return value from the function, which is its result. * @throws NullPointerException If given argument is {@code null} * @see org.apache.commons.lang3.tuple.Triple */ default double applyAsDouble(@Nonnull Triple<T, U, V> tuple) { Objects.requireNonNull(tuple); return applyAsDouble(tuple.getLeft(), tuple.getMiddle(), tuple.getRight()); } /** * Applies this function partially to some arguments of this one, producing a {@link ToDoubleBiFunction2} as result. * * @param t The first argument to this function used to partially apply this function * @return A {@code ToDoubleBiFunction2} that represents this function partially applied the some arguments. */ @Nonnull default ToDoubleBiFunction2<U, V> papplyAsDouble(T t) { return (u, v) -> this.applyAsDouble(t, u, v); } /** * Applies this function partially to some arguments of this one, producing a {@link ToDoubleFunction2} as result. * * @param t The first argument to this function used to partially apply this function * @param u The second argument to this function used to partially apply this function * @return A {@code ToDoubleFunction2} that represents this function partially applied the some arguments. */ @Nonnull default ToDoubleFunction2<V> papplyAsDouble(T t, U u) { return (v) -> this.applyAsDouble(t, u, v); } /** * Returns the number of arguments for this function. * * @return The number of arguments for this function. * @implSpec The default implementation always returns {@code 3}. */ @Nonnegative default int arity() { return 3; } /** * Returns a composed {@link ToDoubleTriFunction} that first applies the {@code before} functions to its input, and * then applies this function to the result. * If evaluation of either operation throws an exception, it is relayed to the caller of the composed operation. * * @param <A> The type of the argument to the first given function, and of composed function * @param <B> The type of the argument to the second given function, and of composed function * @param <C> The type of the argument to the third given function, and of composed function * @param before1 The first function to apply before this function is applied * @param before2 The second function to apply before this function is applied * @param before3 The third function to apply before this function is applied * @return A composed {@code ToDoubleTriFunction} that first applies the {@code before} functions to its input, and * then applies this function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is able to handle every type. */ @Nonnull default <A, B, C> ToDoubleTriFunction<A, B, C> compose(@Nonnull final Function<? super A, ? extends T> before1, @Nonnull final Function<? super B, ? extends U> before2, @Nonnull final Function<? super C, ? extends V> before3) { Objects.requireNonNull(before1); Objects.requireNonNull(before2); Objects.requireNonNull(before3); return (a, b, c) -> applyAsDouble(before1.apply(a), before2.apply(b), before3.apply(c)); } /** * Returns a composed {@link TriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * If evaluation of either operation throws an exception, it is relayed to the caller of the composed operation. * * @param <S> The type of return value from the {@code after} function, and of the composed function * @param after The function to apply after this function is applied * @return A composed {@code TriFunction} that first applies this function to its input, and then applies the {@code * after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is able to return every type. */ @Nonnull default <S> TriFunction<T, U, V, S> andThen(@Nonnull final DoubleFunction<? extends S> after) { Objects.requireNonNull(after); return (t, u, v) -> after.apply(applyAsDouble(t, u, v)); } /** * Returns a composed {@link TriPredicate} that first applies this function to its input, and then applies the * {@code after} predicate to the result. If evaluation of either operation throws an exception, it is relayed to * the caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code boolean}. * * @param after The predicate to apply after this function is applied * @return A composed {@code TriPredicate} that first applies this function to its input, and then applies the * {@code after} predicate to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * boolean}. */ @Nonnull default TriPredicate<T, U, V> andThenToBoolean(@Nonnull final DoublePredicate after) { Objects.requireNonNull(after); return (t, u, v) -> after.test(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToByteTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code byte}. * * @param after The function to apply after this function is applied * @return A composed {@code ToByteTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * byte}. */ @Nonnull default ToByteTriFunction<T, U, V> andThenToByte(@Nonnull final DoubleToByteFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsByte(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToCharTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code char}. * * @param after The function to apply after this function is applied * @return A composed {@code ToCharTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * char}. */ @Nonnull default ToCharTriFunction<T, U, V> andThenToChar(@Nonnull final DoubleToCharFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsChar(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToDoubleTriFunction} that first applies this function to its input, and then applies * the {@code after} operator to the result. If evaluation of either operation throws an exception, it is relayed to * the caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code double}. * * @param after The operator to apply after this function is applied * @return A composed {@code ToDoubleTriFunction} that first applies this function to its input, and then applies * the {@code after} operator to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * double}. */ @Nonnull default ToDoubleTriFunction<T, U, V> andThenToDouble(@Nonnull final DoubleUnaryOperator after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsDouble(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToFloatTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code float}. * * @param after The function to apply after this function is applied * @return A composed {@code ToFloatTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * float}. */ @Nonnull default ToFloatTriFunction<T, U, V> andThenToFloat(@Nonnull final DoubleToFloatFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsFloat(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToIntTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code int}. * * @param after The function to apply after this function is applied * @return A composed {@code ToIntTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * int}. */ @Nonnull default ToIntTriFunction<T, U, V> andThenToInt(@Nonnull final DoubleToIntFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsInt(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToLongTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code long}. * * @param after The function to apply after this function is applied * @return A composed {@code ToLongTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * long}. */ @Nonnull default ToLongTriFunction<T, U, V> andThenToLong(@Nonnull final DoubleToLongFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsLong(applyAsDouble(t, u, v)); } /** * Returns a composed {@link ToShortTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. If evaluation of either operation throws an exception, it is relayed to the * caller of the composed operation. This method is just convenience, to provide the ability to transform this * primitive function to an operation returning {@code short}. * * @param after The function to apply after this function is applied * @return A composed {@code ToShortTriFunction} that first applies this function to its input, and then applies the * {@code after} function to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is a able to return primitive values. In this case this is {@code * short}. */ @Nonnull default ToShortTriFunction<T, U, V> andThenToShort(@Nonnull final DoubleToShortFunction after) { Objects.requireNonNull(after); return (t, u, v) -> after.applyAsShort(applyAsDouble(t, u, v)); } /** * Returns a composed {@link TriConsumer} that fist applies this function to its input, and then consumes the result * using the given {@link DoubleConsumer}. * If evaluation of either operation throws an exception, it is relayed to the caller of the composed operation. * * @param consumer The operation which consumes the result from this operation * @return A composed {@code TriConsumer} that first applies this function to its input, and then consumes the * result using the given {@code DoubleConsumer}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull default TriConsumer<T, U, V> consume(@Nonnull final DoubleConsumer consumer) { Objects.requireNonNull(consumer); return (t, u, v) -> consumer.accept(applyAsDouble(t, u, v)); } /** * Returns a tupled version of this function. * * @return A tupled version of this function. */ @Nonnull default ToDoubleFunction2<Triple<T, U, V>> tupled() { return this::applyAsDouble; } /** * Returns a reversed version of this function. This may be useful in recursive context. * * @return A reversed version of this function. */ @Nonnull default ToDoubleTriFunction<V, U, T> reversed() { return (v, u, t) -> applyAsDouble(t, u, v); } /** * Returns a memoized (caching) version of this {@link ToDoubleTriFunction}. Whenever it is called, the mapping * between the input parameters and the return value is preserved in a cache, making subsequent calls returning the * memoized value instead of computing the return value again. * <p> * Unless the function and therefore the used cache will be garbage-collected, it will keep all memoized values * forever. * * @return A memoized (caching) version of this {@code ToDoubleTriFunction}. * @implSpec This implementation does not allow the input parameters or return value to be {@code null} for the * resulting memoized function, as the cache used internally does not permit {@code null} keys or values. * @implNote The returned memoized function can be safely used concurrently from multiple threads which makes it * thread-safe. */ @Nonnull default ToDoubleTriFunction<T, U, V> memoized() { if (isMemoized()) { return this; } else { final Map<Triple<T, U, V>, Double> cache = new ConcurrentHashMap<>(); final Object lock = new Object(); return (ToDoubleTriFunction<T, U, V> & Memoized) (t, u, v) -> { final double returnValue; synchronized (lock) { returnValue = cache.computeIfAbsent(Triple.of(t, u, v), key -> applyAsDouble(key.getLeft(), key.getMiddle(), key.getRight())); } return returnValue; }; } } /** * Returns a composed {@link TriFunction} which represents this {@link ToDoubleTriFunction}. Thereby the primitive * input argument for this function is autoboxed. This method provides the possibility to use this * {@code ToDoubleTriFunction} with methods provided by the {@code JDK}. * * @return A composed {@code TriFunction} which represents this {@code ToDoubleTriFunction}. */ @Nonnull default TriFunction<T, U, V, Double> boxed() { return this::applyAsDouble; } }