From 84426ae452127759ceb6126e7e5c59d08a506a0d Mon Sep 17 00:00:00 2001 From: Zihlu Wang Date: Sat, 29 Jul 2023 22:56:11 +0800 Subject: [PATCH] feat(devkit-core): added BranchUtil BranchUtil reduces if...else... code blocks by using lambda expressions. --- .../org/codecrafters/devutils/BranchUtil.java | 215 ++++++++++++++++++ 1 file changed, 215 insertions(+) create mode 100644 dev-utils/src/main/java/cn/org/codecrafters/devutils/BranchUtil.java diff --git a/dev-utils/src/main/java/cn/org/codecrafters/devutils/BranchUtil.java b/dev-utils/src/main/java/cn/org/codecrafters/devutils/BranchUtil.java new file mode 100644 index 0000000..00624c0 --- /dev/null +++ b/dev-utils/src/main/java/cn/org/codecrafters/devutils/BranchUtil.java @@ -0,0 +1,215 @@ +/* + * Copyright (C) 2023 CodeCraftersCN. + * + * 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 cn.org.codecrafters.devutils; + +import java.util.Arrays; +import java.util.Objects; +import java.util.function.BooleanSupplier; +import java.util.function.Supplier; + +/** + * Utility class to simplify if...else logic using lambda expressions. + *

+ * The BranchUtil class provides static methods to simplify conditional + * logic in Java development by leveraging lambda expressions. It offers + * convenient methods to replace verbose if...else statements with more + * concise and expressive functional constructs. + *

+ * Developers can use the methods in this utility class to streamline + * their code, enhance readability, and promote a more functional style + * of programming when dealing with branching logic and conditional + * statements. + *

+ * Example: + * 

+ * // If you want to simplify an if (exp1 || exp2), you can use the
+ * // following code:
+ * var r1 = BranchUtil.or(1 == 1, 2 == 1)
+ *     .handle(() -> "1 is equal to 1 or 2 is equal to 1.");
+ *
+ * // If you have an else branch, you can use the following code:
+ * var r2 = BranchUtil.or(1 == 1, 2 == 1)
+ *     .handle(() -> "1 is equal to 1 or 2 is equal to 1.",
+ *             () -> "1 is not equal to 1 and 2 is not equal to 1.");
+ *
+ * // If you only need to execute code without a return value:
+ * BranchUtil.or(1 == 1, 2 == 1)
+ *     .handle(() -> {
+ *         // do something
+ *     }, () -> {
+ *         // do something
+ *     });
+ * // If you only need an if branch, you can remove the second Supplier instance.
+ *
+ * // To check if all boolean expressions are true, use the 'and' method:
+ * BranchUtil.and(1 == 1, 2 == 1)
+ *     .handle(() -> {
+ *         // do something
+ *     }, () -> {
+ *         // do something
+ *     });
+ *
+ * + * Note: + * The {@link #and(Boolean...)} and {@link #or(Boolean...)} methods accept any number of boolean expressions. + *

+ * Created on 9 Jul 2023. + * + * @param the type of the result to be handled by the methods + * @see java.util.function.Supplier + * @see java.util.function.BooleanSupplier + * @see java.lang.Runnable + * @since 9 Jul 2023 + * @version 1.0.0 + * @author Zihlu Wang + */ +public final class BranchUtil { + + /** + * The final result of the boolean expression. + */ + private final boolean result; + + /** + * Create a {@code BranchUtil} instance. + * + * @param result the result of the boolean expressions. + */ + private BranchUtil(boolean result) { + this.result = result; + } + + /** + * Creates a {@code BranchUtil} instance to evaluate a logical OR operation on the provided boolean expressions. + * + * @param booleans the boolean expressions to be evaluated + * @param the type of the result to be handled by the methods + * @return a {@code BranchUtil} instance representing the result of the logical OR operation + */ + public static BranchUtil or(Boolean... booleans) { + var result = Arrays.stream(booleans) + .filter(Objects::nonNull) + .anyMatch(Boolean::booleanValue); + return new BranchUtil<>(result); + } + + /** + * Creates a {@code BranchUtil} instance to evaluate a logical AND operation on the provided boolean expressions. + * + * @param booleans the boolean expressions to be evaluated + * @param the type of the result to be handled by the methods + * @return a {@code BranchUtil} instance representing the result of the logical AND operation + */ + public static BranchUtil and(Boolean... booleans) { + var result = Arrays.stream(booleans) + .filter(Objects::nonNull) + .allMatch(Boolean::booleanValue); + return new BranchUtil<>(result); + } + + /** + * Creates a {@code BranchUtil} instance to evaluate a logical OR operation on the provided boolean suppliers. + * + * @param booleanSuppliers the boolean suppliers to be evaluated + * @param the type of the result to be handled by the methods + * @return a {@code BranchUtil} instance representing the result of the logical OR operation + */ + public static BranchUtil or(BooleanSupplier... booleanSuppliers) { + var result = Arrays.stream(booleanSuppliers) + .filter(Objects::nonNull) + .anyMatch(BooleanSupplier::getAsBoolean); + return new BranchUtil<>(result); + } + + /** + * Creates a {@code BranchUtil} instance to evaluate a logical AND operation on the provided boolean suppliers. + * + * @param booleanSuppliers the boolean suppliers to be evaluated + * @param the type of the result to be handled by the methods + * @return a {@code BranchUtil} instance representing the result of the logical AND operation + */ + public static BranchUtil and(BooleanSupplier... booleanSuppliers) { + var result = Arrays.stream(booleanSuppliers) + .filter(Objects::nonNull) + .allMatch(BooleanSupplier::getAsBoolean); + return new BranchUtil<>(result); + } + + /** + * Handles the result of the boolean expressions by executing the appropriate handler based on the result. + * If the result is {@code true}, the {@code ifHandler} is executed. If the result is {@code false} and an + * {@code elseHandler} is provided, it is executed. Returns the result of the executed handler. + * + * @param ifHandler the handler to be executed if the result is {@code true} + * @param elseHandler the handler to be executed if the result is {@code false} (optional) + * @return the result of the executed handler, or {@code null} if no elseHandler is provided + */ + public T handle(Supplier ifHandler, Supplier elseHandler) { + if (this.result && Objects.nonNull(ifHandler)) { + return ifHandler.get(); + } + + if (Objects.isNull(elseHandler)) { + return null; + } + + return elseHandler.get(); + } + + /** + * Handles the result of the boolean expressions by executing the provided handler if the result is {@code true}. + * Returns the result of the executed handler. + * + * @param ifHandler the handler to be executed if the result is {@code true} + * @return the result of the executed handler + */ + public T handle(Supplier ifHandler) { + return handle(ifHandler, null); + } + + /** + * Handles the result of the boolean expressions by executing the appropriate handler based on the result. + * If the result is {@code true}, the {@code ifHandler} is executed. If the result is {@code false} and an + * {@code elseHandler} is provided, it is executed. + * + * @param ifHandler the handler to be executed if the result is {@code true} + * @param elseHandler the handler to be executed if the result is {@code false} (optional) + */ + public void handle(Runnable ifHandler, Runnable elseHandler) { + if (this.result && Objects.nonNull(ifHandler)) { + ifHandler.run(); + return; + } + + if (Objects.isNull(elseHandler)) { + return; + } + + elseHandler.run(); + } + + /** + * Handles the result of the boolean expressions by executing the provided handler if the result is {@code true}. + * + * @param ifHandler the handler to be executed if the result is {@code true} + */ + public void handle(Runnable ifHandler) { + handle(ifHandler, null); + } + +}