程式碼風格
我們遵循 Google’s Java Style Guidelines 以及一些補充與更動,詳述於下。
小訣竅
你可以在 Eclipse 或 IntelliJ IDEA 上使用我们的代码样式来让你的 IDE 正确格式化代码。详情可以查看 ` Sponge 代码样式<https://github.com/SpongePowered/SpongeAPI/tree/api-8/extra>`_.
行尾
在提交時使用 Unix 行尾(\n)
Windows 的 Git 使用者可以用
git config --global core.autocrlf true
來讓 Git 進行自動轉換
欄寬
Javadocs:80字元
程式碼:150字元
若對可讀性有所助益,請自由換行
縮排
使用4個空格來縮排,不要只用2個空格
空行
在 class、interface、enum 等宣告的第一個成員之前(例如在
class Example {
之後)以及在最後一個成員之後放置一個空行
檔頭
檔頭必須包含專案的授權協議標頭。使用
updateLicenses
Gradle 任務來自動添加。
Import
Import 必須按照以下順序進行分組,每組之間由一個空行分隔
Static import
所有其他 import
java
importjavax
import
這與Google的風格不同,因為 import 不是按照 top-level package 分組的,它們都被分在同一個組。
例外
對於要被忽略的例外,將例外變數命名為
ignored
屬性存取
使用
this
存取 所有的 欄位(Field)
Javadocs
不要使用
@author
將額外段落包進
<p>
與</p>
中在每個「@子句」內的描述中,首字母大寫,即
@param name Player to affect
,不要有句號
檔案結尾
每個檔案的結尾應有一行空白行
程式碼慣例
使用 Optionals 而不是在 API 中回傳
null
接受
null
的方法參數必須註解為@Nullable
(來自 javax.*),預設所有的方法和參數都是@Nonnull
。API:使用
java.util.Objects.requireNonNull
进行空值检查,if
s 进行参数检查。实现:使用 Google Preconditions 进行空值及参数检查。
Gist
雖然我們強烈建議您閱讀 Google 的 Java 慣例,但這兩份文件都相當長。 為了讓您快速入門,下面是格式正確的程式碼範例:
/*
* This file is part of Sponge, licensed under the MIT License (MIT).
*
* Copyright (c) SpongePowered <https://www.spongepowered.org>
* Copyright (c) contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.spongepowered.example;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.inject.Inject;
import org.slf4j.Logger;
import java.util.Optional;
import java.util.Random;
import java.util.concurrent.ThreadLocalRandom;
import javax.annotation.Nullable;
/**
* An example class which generates a new ID based on a specified base string
* and a randomly generated integer.
*
* <p>There is a chance the integer purposely fails to generate, in which case
* you can choose to provide a backup integer.</p>
*/
public class Example {
private static final long SEED = 4815162342L;
@Inject
private Logger logger;
private final String base;
private final Random random;
public Example(String base) {
checkNotNull(base, "The specified base string cannot be null!");
this.base = base;
this.random = ThreadLocalRandom.current();
this.random.setSeed(SEED);
}
/**
* Generates and returns an ID using the base string specified on creation
* or the alternative string if specified as well as a randomly generated
* integer, which purposely fails to generate around 50% of the time.
*
* <p>A {@link ThreadLocalRandom} is used to check if the integer should
* be generated and generates the integer itself if so.</p>
*
* @param alternate An alternate base string which will be used if not null
* @return The generated ID, if available
*/
public Optional<String> generateId(@Nullable String alternate) {
if (this.random.nextBoolean()) {
return Optional.of(alternate == null ? this.base : alternate + " - " + this.random.nextInt());
}
return Optional.empty();
}
/**
* Generates and returns an ID using the base string specified on creation,
* using a randomly generated integer if it was generated successfully, or
* using the backup integer you specify.
*
* <p>A {@link ThreadLocalRandom} is used to check if the integer should
* be generated and generates the integer itself if so. If it was not
* generated, that is when your backup integer will be used.</p>
*
* @param backup A backup integer to use to create the ID with
* @return The generated ID using the generated integer or the ID created
* using the backup integer specified
*/
public String generateId(int backup) {
return generateId(null).orElse(this.base + " - " + backup);
}
}