blocks|key|1155830|text|你也可以尝试从这里开始遵循建议：http://www.artima.com/weblogs/viewpost.jsp?thread=118828|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1155831|int+value;+int+location;+boolean+overwrite;
doIt(value=13,+location=47,+overwrite=true);|code-block|syntax|javascript|1155832|它在调用站点上是冗长的，但总体上提供了最低的开销。|1155833|entityMap|0|LINK|mutability|MUTABLE|url|http://www.artima.com/weblogs/viewpost.jsp?thread=118828^0|G|1K|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

You could also try to follow advise from here:
<a href="http://www.artima.com/weblogs/viewpost.jsp?thread=118828" rel="noreferrer">http://www.artima.com/weblogs/viewpost.jsp?thread=118828</a>

<pre><code>int value; int location; boolean overwrite;
doIt(value=13, location=47, overwrite=true);
</code></pre>

It's verbose on the call site, but overall gives the lowest overhead.

blocks|key|1155691|text|Java不支持构造函数或方法参数的类Objective-C命名参数。此外，这真的不是Java的处理方式。在java中，典型的模式是冗长命名的类和成员。类和变量应该是名词，命名的方法应该是动词。我认为您可以发挥创造力，偏离Java命名约定，以一种老套的方式模拟Objective-C范例，但负责维护代码的普通Java开发人员不会特别欣赏这一点。在使用任何语言工作时，都应该遵守语言和社区的约定，尤其是在团队中工作时。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1155692|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Java does not support Objective-C-like named parameters for constructors or method arguments. Furthermore, this is really not the Java way of doing things. In java, the typical pattern is verbosely named classes and members. Classes and variables should be nouns and method named should be verbs. I suppose you could get creative and deviate from the Java naming conventions and emulate the Objective-C paradigm in a hacky way but this wouldn't be particularly appreciated by the average Java developer charged with maintaining your code. When working in any language, it behooves you to stick to the conventions of the language and community, especially when working on a team.

blocks|key|1155725|text|如果您使用的是Java6，那么您可以使用变量参数和import+static来产生更好的结果。有关详细信息，请参阅：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1155726|http://zinzel.blogspot.com/2010/07/creating-methods-with-named-parameters.html|offset|length|1155727|简而言之，你可以有这样的东西：|1155728|go();
go(min(0));
go(min(0),+max(100));
go(max(100),+min(0));
go(prompt("Enter+a+value"),+min(0),+max(100));|code-block|syntax|javascript|1155729|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|26|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@$D|V|E|W|1|X]]|A|$]]|$1|F|3|G|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Z|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|C]]]]

If you are using Java 6, you can use the variable parameters and import static to produce a much better result. Details of this are found in: 

<a href="http://zinzel.blogspot.com/2010/07/creating-methods-with-named-parameters.html" rel="noreferrer">http://zinzel.blogspot.com/2010/07/creating-methods-with-named-parameters.html</a>

In short, you could have something like:

<pre><code>go();
go(min(0));
go(min(0), max(100));
go(max(100), min(0));
go(prompt("Enter a value"), min(0), max(100));
</code></pre>

blocks|key|1370832|text|关于|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370833|public+class+Tiger+{
String+myColor;
int++++myLegs;

public+Tiger+color(String+s)
{
++++myColor+=+s;
++++return+this;
}

public+Tiger+legs(int+i)
{
++++myLegs+=+i;
++++return+this;
}
}

Tiger+t+=+new+Tiger().legs(4).color("striped");|code-block|syntax|javascript|1370834|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

What about

<pre><code>public class Tiger {
String myColor;
int myLegs;

public Tiger color(String s)
{
 myColor = s;
 return this;
}

public Tiger legs(int i)
{
 myLegs = i;
 return this;
}
}

Tiger t = new Tiger().legs(4).color("striped");
</code></pre>

blocks|key|1371137|text|我觉得“注释-变通方法”应该有它自己的答案(隐藏在现有的答案中，并在这里的评论中提到)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1371138|someMethod(/*+width+*/+1024,+/*+height+*/+768);|code-block|syntax|javascript|1371139|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I feel like the "comment-workaround" deserves it's own answer (hidden in existing answers and mentioned in comments here).

<pre><code>someMethod(/* width */ 1024, /* height */ 768);
</code></pre>

blocks|key|1371069|text|您可以使用项目Lombok的@Builder+annotation在Java语言中模拟命名参数。这将为您生成一个构建器，您可以使用它来创建任何类的新实例(包括您编写的类和来自外部库的类)。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1371070|下面是如何在一个类上启用它：|1371071|@Getter
@Builder
public+class+User+{
++++private+final+Long+id;
++++private+final+String+name;
}|code-block|syntax|javascript|1371072|之后，您可以通过以下方式使用它：|1371073|User+userInstance+=+User.builder()
++++.id(1L)
++++.name("joe")
++++.build();|1371074|如果您想为来自库的类创建这样的生成器，请创建一个带注释的静态方法，如下所示：|1371075|class+UserBuilder+{
++++@Builder(builderMethodName+=+"builder")
++++public+static+LibraryUser+newLibraryUser(Long+id,+String+name)+{
++++++++return+new+LibraryUser(id,+name);
++++}
++}|1371076|这将生成一个名为"builder“的方法，可以通过以下方式调用该方法：|1371077|LibraryUser+user+=+UserBuilder.builder()
++++.id(1L)
++++.name("joe")
++++.build();|1371078|entityMap|0|LINK|mutability|MUTABLE|url|https://projectlombok.org/features/Builder^0|E|J|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|6|7|18|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|19|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|1A|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|1B|8|@]|9|@]|C|$I|J]]|$1|O|3|P|5|6|7|1C|8|@]|9|@]|C|$]]|$1|Q|3|R|5|H|7|1D|8|@]|9|@]|C|$I|J]]|$1|S|3|T|5|6|7|1E|8|@]|9|@]|C|$]]|$1|U|3|V|5|H|7|1F|8|@]|9|@]|C|$I|J]]|$1|W|3|-4|5|6|7|1G|8|@]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]]]

You can use project Lombok's <a href="https://projectlombok.org/features/Builder" rel="nofollow noreferrer">@Builder annotation</a> to simulate named parameters in Java. This will generate a builder for you which you can use to create new instances of any class (both classes you've written and those coming from external libraries).

This is how to enable it on a class:

<pre><code>@Getter
@Builder
public class User {
 private final Long id;
 private final String name;
}
</code></pre>

Afterwards you can use this by:

<pre><code>User userInstance = User.builder()
 .id(1L)
 .name("joe")
 .build();
</code></pre>

If you'd like to create such a Builder for a class coming from a library, create an annotated static method like this:

<pre><code>class UserBuilder {
 @Builder(builderMethodName = "builder")
 public static LibraryUser newLibraryUser(Long id, String name) {
 return new LibraryUser(id, name);
 }
 }
</code></pre>

This will generate a method named "builder" which can be called by:

<pre><code>LibraryUser user = UserBuilder.builder()
 .id(1L)
 .name("joe")
 .build();
</code></pre>

blocks|key|1155886|text|Java语言中的任何解决方案都可能非常冗长，但值得一提的是，Google+AutoValues和Immutables等工具将使用JDK编译时批注处理自动生成构建器类。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1155887|在我的例子中，我希望在Java枚举中使用命名参数，因此构建器模式不起作用，因为枚举实例不能被其他类实例化。我想出了一个类似@deamon的答案的方法，但添加了参数排序的编译时检查(以更多代码为代价)|1155888|以下是客户端代码：|1155889|Person+p+=+new+Person(+age(16),+weight(100),+heightInches(65)+);|code-block|syntax|javascript|1155890|以及实现方法：|1155891|class+Person+{
++static+class+TypedContainer<T>+{
++++T+val;
++++TypedContainer(T+val)+{+this.val+=+val;+}
++}
++static+Age+age(int+age)+{+return+new+Age(age);+}
++static+class+Age+extends+TypedContainer<Integer>+{
++++Age(Integer+age)+{+super(age);+}
++}
++static+Weight+weight(int+weight)+{+return+new+Weight(weight);+}
++static+class+Weight+extends+TypedContainer<Integer>+{
++++Weight(Integer+weight)+{+super(weight);+}
++}
++static+Height+heightInches(int+height)+{+return+new+Height(height);+}
++static+class+Height+extends+TypedContainer<Integer>+{
++++Height(Integer+height)+{+super(height);+}
++}

++private+final+int+age;
++private+final+int+weight;
++private+final+int+height;

++Person(Age+age,+Weight+weight,+Height+height)+{
++++this.age+=+age.val;
++++this.weight+=+weight.val;
++++this.height+=+height.val;
++}
++public+int+getAge()+{+return+age;+}
++public+int+getWeight()+{+return+weight;+}
++public+int+getHeight()+{+return+height;+}
}|1155892|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/google/auto/tree/master/value|1|https://immutables.github.io/^0|U|H|0|1C|A|1|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]|$A|14|B|15|1|16]]|C|$]]|$1|D|3|E|5|6|7|17|8|@]|9|@]|C|$]]|$1|F|3|G|5|6|7|18|8|@]|9|@]|C|$]]|$1|H|3|I|5|J|7|19|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1A|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1B|8|@]|9|@]|C|$K|L]]|$1|Q|3|-4|5|6|7|1C|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]|Y|$5|T|U|V|C|$W|Z]]]]

Any solution in Java is likely going to be pretty verbose, but it's worth mentioning that tools like <a href="https://github.com/google/auto/tree/master/value" rel="nofollow noreferrer">Google AutoValues</a> and <a href="https://immutables.github.io/" rel="nofollow noreferrer">Immutables</a> will generate builder classes for you automatically using JDK compile time annotation processing.

For my case, I wanted named parameters to use in a Java enum, so a builder pattern wouldn't work because enum instances can't be instantiated by other classes. I came up with an approach similar @deamon's answer but adds compile-time checking of parameter ordering (at the expense of more code)

Here's client code:

<pre><code>Person p = new Person( age(16), weight(100), heightInches(65) );
</code></pre>

And the implementation:

<pre><code>class Person {
 static class TypedContainer&lt;T&gt; {
 T val;
 TypedContainer(T val) { this.val = val; }
 }
 static Age age(int age) { return new Age(age); }
 static class Age extends TypedContainer&lt;Integer&gt; {
 Age(Integer age) { super(age); }
 }
 static Weight weight(int weight) { return new Weight(weight); }
 static class Weight extends TypedContainer&lt;Integer&gt; {
 Weight(Integer weight) { super(weight); }
 }
 static Height heightInches(int height) { return new Height(height); }
 static class Height extends TypedContainer&lt;Integer&gt; {
 Height(Integer height) { super(height); }
 }

 private final int age;
 private final int weight;
 private final int height;

 Person(Age age, Weight weight, Height height) {
 this.age = age.val;
 this.weight = weight.val;
 this.height = height.val;
 }
 public int getAge() { return age; }
 public int getWeight() { return weight; }
 public int getHeight() { return height; }
}
</code></pre>

blocks|key|1155799|text|karg+library支持的习惯用法可能值得考虑：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1155800|class+Example+{

++++private+static+final+Keyword<String>+GREETING+=+Keyword.newKeyword();
++++private+static+final+Keyword<String>+NAME+=+Keyword.newKeyword();

++++public+void+greet(KeywordArgument...argArray)+{
++++++++KeywordArguments+args+=+KeywordArguments.of(argArray);
++++++++String+greeting+=+GREETING.from(args,+"Hello");
++++++++String+name+=+NAME.from(args,+"World");
++++++++System.out.println(String.format("%25s,+%25s!",+greeting,+name));
++++}

++++public+void+sayHello()+{
++++++++greet();
++++}

++++public+void+sayGoodbye()+{
++++++++greet(GREETING.of("Goodbye");
++++}

++++public+void+campItUp()+{
++++++++greet(NAME.of("Sailor");
++++}
}|code-block|syntax|javascript|1155801|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/youdevise/karg^0|0|C|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

The idiom supported by the <a href="https://github.com/youdevise/karg" rel="nofollow">karg library</a> may be worth considering:

<pre><code>class Example {

 private static final Keyword&lt;String&gt; GREETING = Keyword.newKeyword();
 private static final Keyword&lt;String&gt; NAME = Keyword.newKeyword();

 public void greet(KeywordArgument...argArray) {
 KeywordArguments args = KeywordArguments.of(argArray);
 String greeting = GREETING.from(args, "Hello");
 String name = NAME.from(args, "World");
 System.out.println(String.format("%s, %s!", greeting, name));
 }

 public void sayHello() {
 greet();
 }

 public void sayGoodbye() {
 greet(GREETING.of("Goodbye");
 }

 public void campItUp() {
 greet(NAME.of("Sailor");
 }
}
</code></pre>

blocks|key|1156153|text|您可以应用此模式模拟命名参数：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1156154|public+static+class+CarParameters+{
++++++++
++++//+to+make+it+shorter+getters+and+props+are+omitted
++++++++
++++public+ModelParameter+setName(String+name)+{
++++++++this.name+=+name;
++++++++return+new+ModelParameter();
++++}
++++public+class+ModelParameter+{
++++++++public+PriceParameter+setModel(String+model)+{
++++++++++++CarParameters.this.model+=+model;
++++++++++++return+new+PriceParameter();
++++++++}
++++}
++++public+class+PriceParameter+{
++++++++public+YearParameter+setPrice(double+price)+{
++++++++++++CarParameters.this.price+=+price;
++++++++++++return+new+YearParameter();
++++++++}
++++}
++++public+class+YearParameter+{
++++++++public+ColorParameter+setYear(int+year)+{
++++++++++++CarParameters.this.year+=+year;
++++++++++++return+new+ColorParameter();
++++++++}
++++}
++++public+class+ColorParameter+{
++++++++public+CarParameters+setColor(Color+color)+{
++++++++++++CarParameters.this.color+=+color;
++++++++++++return+new+CarParameters();
++++++++}
++++}
}|code-block|syntax|javascript|1156155|然后，您可以将其传递给您的方法，如下所示：|1156156|factory.create(new+CarParameters()
++++++++.setName("Ford")
++++++++.setModel("Focus")
++++++++.setPrice(20000)
++++++++.setYear(2011)
++++++++.setColor(BLUE));|1156157|您可以在这里阅读更多内容https://medium.com/@ivorobioff/named-parameters-in-java-9072862cfc8c|offset|length|1156158|entityMap|0|LINK|mutability|MUTABLE|url|https://medium.com/@ivorobioff/named-parameters-in-java-9072862cfc8c^0|0|0|0|0|C|1W|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|Z|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

You can imitate named parameters applying this pattern:
<pre><code>public static class CarParameters {
 
 // to make it shorter getters and props are omitted
 
 public ModelParameter setName(String name) {
 this.name = name;
 return new ModelParameter();
 }
 public class ModelParameter {
 public PriceParameter setModel(String model) {
 CarParameters.this.model = model;
 return new PriceParameter();
 }
 }
 public class PriceParameter {
 public YearParameter setPrice(double price) {
 CarParameters.this.price = price;
 return new YearParameter();
 }
 }
 public class YearParameter {
 public ColorParameter setYear(int year) {
 CarParameters.this.year = year;
 return new ColorParameter();
 }
 }
 public class ColorParameter {
 public CarParameters setColor(Color color) {
 CarParameters.this.color = color;
 return new CarParameters();
 }
 }
}
</code></pre>
and then you can pass it to your method as this:
<pre><code>factory.create(new CarParameters()
 .setName(&quot;Ford&quot;)
 .setModel(&quot;Focus&quot;)
 .setPrice(20000)
 .setYear(2011)
 .setColor(BLUE));
</code></pre>
You can read more here <a href="https://medium.com/@ivorobioff/named-parameters-in-java-9072862cfc8c" rel="nofollow noreferrer">https://medium.com/@ivorobioff/named-parameters-in-java-9072862cfc8c</a>

blocks|key|1156244|text|现在我们都在使用Java+17+;-)，使用记录是模仿这个成语的一种超级简单的方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1156245|public+class+OrderTemplate()+{
++++private+int+tradeSize,+limitDistance,+backoffDistance;

++++public+record+TradeSize(+int+value+)+{}
++++public+record+LimitDistance(+int+value+)+{}
++++public+record+BackoffDistance(+int+value+)+{}
++++public+OrderTemplate(+TradeSize+t,+LimitDistance+d,+BackoffDistance+b+)+{
++++++this.tradeSize+=+t.value();
++++++this.limitDistance+=+d.value();
++++++this.backoffDistance+=+b.value();
++++}
}|code-block|syntax|javascript|1156246|然后你可以调用：|1156247|var+t+=+new+OrderTemplate(+new+TradeSize(30),+new+LimitDistance(182),+new+BackoffDistance(85)+);|1156248|我发现它非常容易阅读，并且我已经完全停止了将所有int参数弄混(“它是大小优先还是距离...”)。|1156249|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Now that we're all on Java 17 ;-), using records is a super-easy way to imitate this idiom:
<pre><code>public class OrderTemplate() {
 private int tradeSize, limitDistance, backoffDistance;

 public record TradeSize( int value ) {}
 public record LimitDistance( int value ) {}
 public record BackoffDistance( int value ) {}
 public OrderTemplate( TradeSize t, LimitDistance d, BackoffDistance b ) {
 this.tradeSize = t.value();
 this.limitDistance = d.value();
 this.backoffDistance = b.value();
 }
}
</code></pre>
Then you can call:
<pre><code>var t = new OrderTemplate( new TradeSize(30), new LimitDistance(182), new BackoffDistance(85) );
</code></pre>
Which I've found extremely easy to read and I've completely stopped getting all the int parameters mixed up (&quot;was it size first or distance...&quot;).

blocks|key|1371276|text|package+org.xxx.lang;

/**
+*+A+hack+to+work+around+the+fact+that+java+does+not+support
+*+named+parameters+in+function+calls.
+*+
+*+Its+easy+to+swap+a+few+String+parameters,+for+example.
+*+Some+IDEs+are+better+than+others+than+showing+the+parameter+names.
+*+This+will+enforce+a+compiler+error+on+an+inadvertent+swap.+
+*
+*+@param+<T>
+*/
public+class+Datum<T>+{

++++public+final+T+v;
++++
++++public+Datum(T+v)+{
++++++++this.v+=+v;
++++}
++++
++++public+T+v()+{
++++++++return+v;
++++}
++++
++++public+T+value()+{
++++++++return+v;
++++}
++++
++++public+String+toString()+{
++++++++return+v.toString();
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1371277|示例|unstyled|1371278|class+Catalog+extends+Datum<String>+{
++++++++public+Catalog(String+v)+{
++++++++++++super(v);
++++++++}
++++}

++++class+Schema+extends+Datum<String>+{
++++++++public+Schema(String+v)+{
++++++++++++super(v);
++++++++}
++++}
class+Meta+{
++++++++public+void+getTables(String+catalog,+String+schema,+String+tablePattern)+{
++++++++++++//+pseudo+DatabaseMetaData.getTables();
++++++++}
++++}
++++
++++class+MetaChecked+{
++++++++public+void+getTables(Catalog+catalog,+Schema+schema,+String+tablePattern)+{
++++++++++++//+pseudo+DatabaseMetaData.getTables();
++++++++}
++++}

++++@Test
++++public+void+test()+{
++++++++Catalog+c+=+new+Catalog("test");
++++++++assertEquals("test",c.v);
++++++++assertEquals("test",c.v());
++++++++assertEquals("test",c.value());
++++++++String+t+=+c.v;
++++++++assertEquals("test",t);
++++}

++++public+void+uncheckedExample()+{
++++++++new+Meta().getTables("schema","catalog","%25");+
++++++++new+Meta().getTables("catalog","schema","%25");+//+ooops
++++}
++++
++++public+void+checkedExample()+{
+++++++++//+new+MetaChecked().getTables(new+Schema("schema"),new+Catalog("catalog"),"%25");+//+won't+compile
++++++++++new+MetaChecked().getTables(new+Catalog("catalog"),+new+Schema("schema"),"%25");+
++++}|1371279|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>package org.xxx.lang;

/**
 * A hack to work around the fact that java does not support
 * named parameters in function calls.
 * 
 * Its easy to swap a few String parameters, for example.
 * Some IDEs are better than others than showing the parameter names.
 * This will enforce a compiler error on an inadvertent swap. 
 *
 * @param &lt;T&gt;
 */
public class Datum&lt;T&gt; {

 public final T v;
 
 public Datum(T v) {
 this.v = v;
 }
 
 public T v() {
 return v;
 }
 
 public T value() {
 return v;
 }
 
 public String toString() {
 return v.toString();
 }
}
</code></pre>
<h1>Example</h1>
<pre><code>class Catalog extends Datum&lt;String&gt; {
 public Catalog(String v) {
 super(v);
 }
 }

 class Schema extends Datum&lt;String&gt; {
 public Schema(String v) {
 super(v);
 }
 }
class Meta {
 public void getTables(String catalog, String schema, String tablePattern) {
 // pseudo DatabaseMetaData.getTables();
 }
 }
 
 class MetaChecked {
 public void getTables(Catalog catalog, Schema schema, String tablePattern) {
 // pseudo DatabaseMetaData.getTables();
 }
 }

 @Test
 public void test() {
 Catalog c = new Catalog(&quot;test&quot;);
 assertEquals(&quot;test&quot;,c.v);
 assertEquals(&quot;test&quot;,c.v());
 assertEquals(&quot;test&quot;,c.value());
 String t = c.v;
 assertEquals(&quot;test&quot;,t);
 }

 public void uncheckedExample() {
 new Meta().getTables(&quot;schema&quot;,&quot;catalog&quot;,&quot;%&quot;); 
 new Meta().getTables(&quot;catalog&quot;,&quot;schema&quot;,&quot;%&quot;); // ooops
 }
 
 public void checkedExample() {
 // new MetaChecked().getTables(new Schema(&quot;schema&quot;),new Catalog(&quot;catalog&quot;),&quot;%&quot;); // won't compile
 new MetaChecked().getTables(new Catalog(&quot;catalog&quot;), new Schema(&quot;schema&quot;),&quot;%&quot;); 
 }
</code></pre>

blocks|key|1370973|text|@irreputable想出了一个很好的解决方案。然而，它可能会使你的Class实例处于无效状态，因为不会发生验证和一致性检查。因此，我更喜欢将其与Builder解决方案相结合，避免创建额外的子类，尽管它仍然会对builder类进行子类化。此外，由于额外的构建器类使其更加冗长，因此我使用lambda添加了另一个方法。为了完整性，我添加了一些其他构建器方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1370974|从一个类开始，如下所示：|1370975|public+class+Foo+{
++static+public+class+Builder+{
++++public+int+size;
++++public+Color+color;
++++public+String+name;
++++public+Builder()+{+size+=+0;+color+=+Color.RED;+name+=+null;+}
++++private+Builder+self()+{+return+this;+}

++++public+Builder+size(int+size)+{this.size+=+size;+return+self();}
++++public+Builder+color(Color+color)+{this.color+=+color;+return+self();}
++++public+Builder+name(String+name)+{this.name+=+name;+return+self();}

++++public+Foo+build()+{return+new+Foo(this);}
++}

++private+final+int+size;
++private+final+Color+color;
++private+final+String+name;

++public+Foo(Builder+b)+{
++++this.size+=+b.size;
++++this.color+=+b.color;
++++this.name+=+b.name;
++}

++public+Foo(java.util.function.Consumer<Builder>+bc)+{
++++Builder+b+=+new+Builder();
++++bc.accept(b);
++++this.size+=+b.size;
++++this.color+=+b.color;
++++this.name+=+b.name;
++}

++static+public+Builder+with()+{
++++return+new+Builder();
++}

++public+int+getSize()+{+return+this.size;+}
++public+Color+getColor()+{+return+this.color;+}++
++public+String+getName()+{+return+this.name;+}++

}|code-block|syntax|javascript|1370976|然后使用这个应用不同的方法：|1370977|Foo+m1+=+new+Foo(
++new+Foo.Builder+()
++.size(1)
++.color(BLUE)
++.name("Fred")
);

Foo+m2+=+new+Foo.Builder()
++.size(1)
++.color(BLUE)
++.name("Fred")
++.build();

Foo+m3+=+Foo.with()
++.size(1)
++.color(BLUE)
++.name("Fred")
++.build();

Foo+m4+=+new+Foo(
++new+Foo.Builder()+{{
++++size+=+1;
++++color+=+BLUE;
++++name+=+"Fred";
++}}
);

Foo+m5+=+new+Foo(
++(b)->{
++++b.size+=+1;
++++b.color+=+BLUE;
++++b.name+=+"Fred";
++}
);|1370978|它看起来像是对@LaurenceGonsalves已经发布的内容的完全抄袭，但您将看到所选择的约定的微小差异。|1370979|我想知道，如果JLS会实现命名参数，他们会怎么做？他们会通过提供一个简短的支持来扩展现有的习惯用法吗？另外，Scala如何支持命名参数？|1370980|嗯-足够研究了，也许还有一个新的问题。|1370981|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|Z|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|10|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|11|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|T|$]]

@irreputable came up with a nice solution. However - it might leave your Class instance in a invalid state, as no validation and consistency checking will happen. Hence I prefer to combine this with the Builder solution, avoiding the extra subclass to be created, although it would still subclass the builder class. Additionally, because the extra builder class makes it more verbose, I added one more method using a lambda. I added some of the other builder approaches for completeness.

Starting with a class as follows:

<pre><code>public class Foo {
 static public class Builder {
 public int size;
 public Color color;
 public String name;
 public Builder() { size = 0; color = Color.RED; name = null; }
 private Builder self() { return this; }

 public Builder size(int size) {this.size = size; return self();}
 public Builder color(Color color) {this.color = color; return self();}
 public Builder name(String name) {this.name = name; return self();}

 public Foo build() {return new Foo(this);}
 }

 private final int size;
 private final Color color;
 private final String name;

 public Foo(Builder b) {
 this.size = b.size;
 this.color = b.color;
 this.name = b.name;
 }

 public Foo(java.util.function.Consumer&lt;Builder&gt; bc) {
 Builder b = new Builder();
 bc.accept(b);
 this.size = b.size;
 this.color = b.color;
 this.name = b.name;
 }

 static public Builder with() {
 return new Builder();
 }

 public int getSize() { return this.size; }
 public Color getColor() { return this.color; } 
 public String getName() { return this.name; } 

}
</code></pre>

Then using this applying the different methods:

<pre><code>Foo m1 = new Foo(
 new Foo.Builder ()
 .size(1)
 .color(BLUE)
 .name("Fred")
);

Foo m2 = new Foo.Builder()
 .size(1)
 .color(BLUE)
 .name("Fred")
 .build();

Foo m3 = Foo.with()
 .size(1)
 .color(BLUE)
 .name("Fred")
 .build();

Foo m4 = new Foo(
 new Foo.Builder() {{
 size = 1;
 color = BLUE;
 name = "Fred";
 }}
);

Foo m5 = new Foo(
 (b)-&gt;{
 b.size = 1;
 b.color = BLUE;
 b.name = "Fred";
 }
);
</code></pre>

It looks like in part a total rip-off from what @LaurenceGonsalves already posted, but you will see the small difference in convention chosen.

I am wonder, if JLS would ever implement named parameters, how they would do it? Would they be extending on one of the existing idioms by providing a short-form support for it? Also how does Scala support named parameters?

Hmmm - enough to research, and maybe a new question.

How to implement Named Parameter idiom in Java? (especially for constructors)
I am looking for an Objective-C like syntax and not like the one used in JavaBeans.
A small code example would be fine.

Named Parameter idiom in Java

Objective-C

Java

如何在Java中实现命名参数习惯用法？(尤其是对于构造函数)我正在寻找一种类似Objective-C的语法，而不是JavaBeans中使用的语法。一个小的代码示例就可以了。

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