Java 8:使用换行符和缩进格式化 lambda [英] Java 8: Formatting lambda with newlines and indentation
问题描述
我想用 lambda 缩进实现如下:
What I would like to achieve with lambda indentation is the following:
多行语句:
String[] ppl = new String[] { "Karen (F)", "Kevin (M)", "Lee (M)", "Joan (F)", "Des (M)", "Rick (M)" };
List<String> strings = Arrays.stream(ppl)
.filter(
(x) ->
{
return x.contains("(M)");
}
).collect(Collectors.toList());
strings.stream().forEach(System.out::println);
单行语句:
List<String> strings = Arrays.stream(ppl)
.map((x) -> x.toUpperCase())
.filter((x) -> x.contains("(M)"))
.collect(Collectors.toList());
目前，Eclipse 正在自动格式化为以下内容:
Currently, Eclipse is auto-formatting to the following:
多行语句:
String[] ppl = new String[] { "Karen (F)", "Kevin (M)", "Lee (M)", "Joan (F)", "Des (M)", "Rick (M)" };
List<String> strings = Arrays.stream(ppl).filter((x) ->
{
return x.contains("(M)");
}).collect(Collectors.toList());
strings.stream().forEach(System.out::println);
单行语句:
String[] ppl = new String[] { "Karen (F)", "Kevin (M)", "Lee (M)", "Joan (F)", "Des(M)", "Rick (M)" };
List<String> strings = Arrays.stream(ppl).map((x) -> x.toUpperCase())
.filter((x) -> x.contains("(M)")).collect(Collectors.toList());
strings.stream().forEach(System.out::println);
而且我发现这真的很混乱，因为 collect 调用是如何直接在 return 下方的，并且两者之间根本没有空格.如果我可以在缩进的新行中启动 lambda，我会更喜欢它，这样 .filter( 调用就在 .collect( 调用之上.但是，唯一可以使用标准 Java-8 Eclipse Formatter 自定义的东西是 lambda 主体开头的大括号，但事先没有 () 括号，也没有缩进.
And I find this really messy, because of how the collect call is directly underneath the return and there's no space inbetween at all. I would prefer it if I could start the lambda in a new line indented, and so that the .filter( call would be right above the .collect( call. However, the only thing that can be customized with standard Java-8 Eclipse Formatter is the brace at the start of the lambda body, but nothing for the () brackets beforehand, nor the indentation.
在单行调用的情况下，它只使用基本的换行并使其成为一个链式混乱.我想我不需要解释为什么这之后很难解密.
And in the case of single-line calls, it just uses the basic line-wrap and makes it be a chained mess. I don't think I need to explain why this is hard to decrypt afterwards.
有什么方法可以以某种方式自定义更多格式并实现 Eclipse 中的第一个格式类型?(或者，可选地，在 IntelliJ IDEA 等另一个 IDE 中.)
Is there any way to somehow customize the formatting more and achieve the first formatting type in Eclipse? (Or, optionally, in another IDE like IntelliJ IDEA.)
我能得到的最接近的是 IntelliJ IDEA 13 社区版(阅读:免费版:P)，如下(由连续缩进定义，在本例中为 8):
The closest I could get was with IntelliJ IDEA 13 Community Edition (read: free edition :P) which was the following (defined by continuous indentation which in this case is 8):
public static void main(String[] args)
{
int[] x = new int[] {1, 2, 3, 4, 5, 6, 7};
int sum = Arrays.stream(x)
.map((n) -> n * 5)
.filter((n) -> {
System.out.println("Filtering: " + n);
return n % 3 != 0;
})
.reduce(0, Integer::sum);
List<Integer> list = Arrays.stream(x)
.filter((n) -> n % 2 == 0)
.map((n) -> n * 4)
.boxed()
.collect(Collectors.toList());
list.forEach(System.out::println);
System.out.println(sum);
它还允许像这样对齐"链接的方法调用:
It also allows to "align" the chained method invocation like this:
int sum = Arrays.stream(x)
.map((n) -> n * 5)
.filter((n) -> {
System.out.println("Filtering: " + n);
return n % 3 != 0;
})
.reduce(0, Integer::sum);
List<Integer> list = Arrays.stream(x)
.filter((n) -> n % 2 == 0)
.map((n) -> n * 4)
.boxed()
.collect(Collectors.toList());
list.forEach(System.out::println);
System.out.println(sum);
}
我个人觉得，虽然第二个版本更有意义，但把它推得太远了，所以我更喜欢第一个.
I personally find that while it makes more sense, the second version pushes it far too away, so I prefer the first one.
负责第一次设置的设置如下:
The setup responsible for the first setup is the following:
<?xml version="1.0" encoding="UTF-8"?>
<code_scheme name="Zhuinden">
<option name="JD_ALIGN_PARAM_COMMENTS" value="false" />
<option name="JD_ALIGN_EXCEPTION_COMMENTS" value="false" />
<option name="JD_ADD_BLANK_AFTER_PARM_COMMENTS" value="true" />
<option name="JD_ADD_BLANK_AFTER_RETURN" value="true" />
<option name="JD_P_AT_EMPTY_LINES" value="false" />
<option name="JD_PARAM_DESCRIPTION_ON_NEW_LINE" value="true" />
<option name="WRAP_COMMENTS" value="true" />
<codeStyleSettings language="JAVA">
<option name="KEEP_FIRST_COLUMN_COMMENT" value="false" />
<option name="BRACE_STYLE" value="2" />
<option name="CLASS_BRACE_STYLE" value="2" />
<option name="METHOD_BRACE_STYLE" value="2" />
<option name="ELSE_ON_NEW_LINE" value="true" />
<option name="WHILE_ON_NEW_LINE" value="true" />
<option name="CATCH_ON_NEW_LINE" value="true" />
<option name="FINALLY_ON_NEW_LINE" value="true" />
<option name="ALIGN_MULTILINE_PARAMETERS" value="false" />
<option name="SPACE_WITHIN_BRACES" value="true" />
<option name="SPACE_BEFORE_IF_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_WHILE_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_FOR_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_TRY_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_CATCH_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_SWITCH_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_SYNCHRONIZED_PARENTHESES" value="false" />
<option name="SPACE_BEFORE_ARRAY_INITIALIZER_LBRACE" value="true" />
<option name="METHOD_PARAMETERS_WRAP" value="1" />
<option name="EXTENDS_LIST_WRAP" value="1" />
<option name="THROWS_LIST_WRAP" value="1" />
<option name="EXTENDS_KEYWORD_WRAP" value="1" />
<option name="THROWS_KEYWORD_WRAP" value="1" />
<option name="METHOD_CALL_CHAIN_WRAP" value="2" />
<option name="BINARY_OPERATION_WRAP" value="1" />
<option name="BINARY_OPERATION_SIGN_ON_NEXT_LINE" value="true" />
<option name="ASSIGNMENT_WRAP" value="1" />
<option name="IF_BRACE_FORCE" value="3" />
<option name="DOWHILE_BRACE_FORCE" value="3" />
<option name="WHILE_BRACE_FORCE" value="3" />
<option name="FOR_BRACE_FORCE" value="3" />
<option name="PARAMETER_ANNOTATION_WRAP" value="1" />
<option name="VARIABLE_ANNOTATION_WRAP" value="1" />
<option name="ENUM_CONSTANTS_WRAP" value="2" />
</codeStyleSettings>
</code_scheme>
我试图确保一切都是合理的，但我可能把事情搞砸了，所以可能需要稍作调整.
I tried to make sure everything is reasonable, but I might have messed something up, so it might need minor adjustments.
如果您像我一样是匈牙利人并且正在使用匈牙利语布局，那么此键盘映射可能对您有用，因此您最终不会无法使用 AltGR+F、AltGR+G、AltGR+B、AltGR+N 和 AltGR+M(对应 Ctrl+Alt).
If you're Hungarian like me and you're using a Hungarian layout, then this keymap might be of use to you, so that you don't end up not being able to use AltGR+F, AltGR+G, AltGR+B, AltGR+N and AltGR+M (which correspond to Ctrl+Alt).
<?xml version="1.0" encoding="UTF-8"?>
<keymap version="1" name="Default copy" parent="$default">
<action id="ExtractMethod">
<keyboard-shortcut first-keystroke="shift control M" />
</action>
<action id="GotoImplementation">
<mouse-shortcut keystroke="control alt button1" />
</action>
<action id="GotoLine">
<keyboard-shortcut first-keystroke="shift control G" />
</action>
<action id="Inline">
<keyboard-shortcut first-keystroke="shift control O" />
</action>
<action id="IntroduceField">
<keyboard-shortcut first-keystroke="shift control D" />
</action>
<action id="Mvc.RunTarget">
<keyboard-shortcut first-keystroke="shift control P" />
</action>
<action id="StructuralSearchPlugin.StructuralReplaceAction" />
<action id="Synchronize">
<keyboard-shortcut first-keystroke="shift control Y" />
</action>
</keymap>
虽然 IntelliJ 似乎没有提供将 lambda 的左大括号放在新行中的方法，但这是一种相当合理的格式化方式，因此我将其标记为已接受.
While IntelliJ doesn't seem to provide a way to put the opening brace of the lambda in a new line, otherwise it's a fairly reasonable way of formatting, so I'll mark this as accepted.
推荐答案
开箱即用的 IntelliJ 13 可能适合您.
Out of the box IntelliJ 13 will probably work for you.
如果我这样写:
// Mulit-Line Statement
String[] ppl = new String[] { "Karen (F)", "Kevin (M)", "Lee (M)", "Joan (F)", "Des (M)", "Rick (M)" };
List<String> strings = Arrays.stream(ppl)
.filter(
(x) ->
{
return x.contains("(M)");
}
).collect(Collectors.toList());
strings.stream().forEach(System.out::println);
然后应用自动格式化程序(无变化):
And then apply the auto formatter (no changes):
// Mulit-Line Statement
String[] ppl = new String[]{"Karen (F)", "Kevin (M)", "Lee (M)", "Joan (F)", "Des (M)", "Rick (M)"};
List<String> strings = Arrays.stream(ppl)
.filter(
(x) ->
{
return x.contains("(M)");
}
).collect(Collectors.toList());
strings.stream().forEach(System.out::println);
单行语句也是如此.根据我的经验，IntelliJ 在应用自动格式化方面更加灵活.IntelliJ 不太可能删除或添加换行符，如果你把它放在那里，那么它假设你打算把它放在那里.IntelliJ 会很乐意为您调整选项卡空间.
The same is true for your single line statement. It has been my experience that IntelliJ is more flexible in how its auto formatting is applied. IntelliJ is less likely to remove or add line returns, if you put it there then it assumes you meant to put it there. IntelliJ will happily adjust your tab-space for you.
IntelliJ 也可以配置为为您执行其中的一些操作.在设置"->代码样式"->java"下，在Wrapping and Braces"选项卡中，您可以将chain method calls"设置为wrap always".
IntelliJ can also be configured to do some of this for you. Under "settings" -> "code style" -> "java", in the "Wrapping and Braces" tab you can set "chain method calls" to "wrap always".
自动格式化之前
// Mulit-Line Statement
List<String> strings = Arrays.stream(ppl).filter((x) -> { return x.contains("(M)"); }).collect(Collectors.toList());
// Single-Line Statement
List<String> strings = Arrays.stream(ppl).map((x) -> x.toUpperCase()).filter((x) -> x.contains("(M)")).collect(Collectors.toList());
自动格式化后
// Mulit-Line Statement
List<String> strings = Arrays.stream(ppl)
.filter((x) -> {
return x.contains("(M)");
})
.collect(Collectors.toList());
// Single-Line Statement
List<String> strings = Arrays.stream(ppl)
.map((x) -> x.toUpperCase())
.filter((x) -> x.contains("(M)"))
.collect(Collectors.toList());
这篇关于Java 8:使用换行符和缩进格式化 lambda的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
