返回Java 8 forEach [英] return about Java 8 forEach

问题描述

 Boolean isSuccess = true;
    if(aMap.size() != bMap.size())
    {
        return false;
    }

    aMap.entrySet().forEach(entry -> {
        AKey aKey = entry.getKey();
        BValue bValue = bMap.get(aKey);

        if(bValue == null)
            return;

        AValue aValue = entry.getValue();
        if(!aValue.getClosed().equals(bValue.getClosed()))
            return;

        if(!aValue.getClosedToArrival().equals(bValue.getClosedToArrival()))
            return;

        if(!aValue.getClosedToDeparture().equals(bValue.getClosedToDeparture()))
            return;

        if(!aValue.getLengthOfStayArrival().equals(bValue.getLengthOfStayArrival()))
            return;
    });

    return isSuccess;

验证失败时如何返回false？
i试图添加返回false，如下所示：

How can i return false when validation failure? i tried to add return false, such as below:

if(!aValue.getLengthOfStayArrival().equals(bValue.getLengthOfStayArrival()))
        return false; 

但这是意料之外的表情，谁能帮我看看？

but it is unexpected expression, who can help me have a look?

推荐答案

您不能返回false，因为您在lambda表达式中实现了Consumer函数接口，该方法属于void类型。

You can't return false because you are in a lambda expression which implement the Consumer functional interface which method is of void type.

相反，请使用anyMatch或noneMatch或allMatch：

Instead, use anyMatch or noneMatch or allMatch :

return aMap.entrySet().stream().anyMatch(entry -> {
    return false;// Put your condition here 
});

我还建议在方法中提取验证，以便管道看起来像这样：

I would also recommend to extract the validation in a method so that your pipeline looks like this :

return aMap.entrySet()
           .stream()
           .anyMatch(this::checkIfMatch);

大部分时间打开 {} ，这是一个很好的迹象，你应该创建一个新的方法。

Most of the times when opening {}, it's a good sign that you should create a new method.

这篇关于返回Java 8 forEach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！