英文:
Is there an object able to chain successive method calls
问题
我有几种方法，它们具有以下模式：
int status = method0();if (status == success) {status = method1();}if (status == success) {status = method2();}if (status == success) {status = method3();}if (status == success) {status = method4();}return status;
我想要使这个代码更可读。我想象中的代码如下：
final CommandPipe pipe = new CommandPipe();status = pipe.next(() -> method0(arg0)).next(() -> method1(arg1)).next(() -> method2(arg2)).next(() -> method3(arg3)).next(() -> method4(arg4)).getResult();return status;
在Java 8中有类似这样的对象吗？
英文:
I have several methods that have the following pattern:
int status = method0();if(status = success){status = method1();}if(status = success){status = method2();}if(status = success){status = method3();}if(status = success){status = method4();}return status
And I would like to make this more readable. I imagine something like this:
final CommandPipe pipe = new CommandPipe();status = pipe.next(() -> method0(arg0)).next(() -> method1(arg1)).next(() -> method2(arg2)).next(() -> method3(arg3)).next(() -> method4(arg4)).getResult();return status;
Is there an object doing this in Java 8 ?
答案1
得分: 2
As of now no.
由于这是您的业务案例框架，不会提供此类功能。
您必须自行构建，否则可以连续使用 CompletableFuture.supplyAsync 和 thenApply 方法，以更好地利用资源的线程。
英文:
As of now no.
Since its your business case frameworks wont provide such a things.
You have to construct yourself or else you can use CompletableFuture.supplyAsync and thenApply methods successively for better thread utilization of resources.
答案2
得分: 2
使用一个 List<IntSupplier> 和一个 for 循环：
int method(List<IntSupplier> list) {int status = success;for (Iterator<IntSupplier> it = list.iterator(); status == success && it.hasNext();) {status = it.next().get();}return status;}
调用方式如下：
int status = method(List.of(() -> method0(arg0),() -> method1(arg1) /* etc */));
（是的，List.of 是 Java 9 的方法。您可以以任何方式构建您的列表）。
您的 CommandPipe 类会很容易编写：
class CommandPipe {int status = success;CommandPipe next(IntSupplier supplier) {if (status == success) {status = supplier.get();}return this;}int getResult() { return status; }}
调用方式与您在问题中提到的方式相同。
英文:
Use a List<IntSupplier> and a for loop:
int method(List<IntSupplier> list) {int status = success;for (Iterator<IntSupplier> it = list.iterator(); status == success && it.hasNext();) {status = it.next().get();}return status;}
Invoke like:
int status = method(List.of(() -> method0(arg0),() -> method1(arg1) /* etc */));
(Sure, List.of is a Java 9 method. Construct your list however you like).
Your CommandPipe class would be quite easy to write:
class CommandPipe {int status = success;CommandPipe next(IntSupplier supplier) {if (status == success) {status = supplier.get();}return this;}int getResult() { return status; }}
Invoke like you wrote in the question.
答案3
得分: 2
以下是您提供的代码的中文翻译部分：
我认为最简单的方法是自己实现这样一种类型，如下所示：public class CommandPipe<T> {private Predicate<T> predicate;private T lastResult = null;private boolean firstInvotion = true;public CommandPipe(Predicate<T> predicate) {this.predicate = predicate;}public CommandPipe next(Supplier<T> supplier) {boolean doStep;if (firstInvotion) {firstInvotion = false;doStep = true;} else {doStep = predicate.test(lastResult);}if (doStep) {lastResult = supplier.get();} else {// 错误处理}return this;}public T getResult() {return lastResult;}}
请注意，我只提供了代码的翻译部分，没有其他内容。
英文:
I think the easiest is to implement such a type yourself, like:
public class CommandPipe<T> {private Predicate<T> predicate;private T lastResult = null;private boolean firstInvotion = true;public CommandPipe(Predicate<T> predicate) {this.predicate = predicate;}public CommandPipe next(Supplier<T> supplier) {boolean doStep;if (firstInvotion) {firstInvotion = false;doStep = true;} else {doStep = predicate.test(lastResult);}if (doStep) {lastResult = supplier.get();} else {// error handling}return this;}public T getResult() {return lastResult;}}
答案4
得分: 0
你可以这样定义一个带有可变参数的静态方法。
public static int pipe(IntSupplier... methods) {int success = 0;int status = success;for (IntSupplier m : methods) {status = m.getAsInt();if (status != success)break;}return status;}
以及
int status = pipe(() -> method0(arg0),() -> method1(arg0),() -> method2(arg0),() -> method3(arg0),() -> method4(arg0));
英文:
You can define a static method with varargs like this.
public static int pipe(IntSupplier... methods) {int success = 0;int status = success;for (IntSupplier m : methods) {status = m.getAsInt();if (status != success)break;}return status;}
and
int status = pipe(() -> method0(arg0),() -> method1(arg0),() -> method2(arg0),() -> method3(arg0),() -> method4(arg0));
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