带有参数的 Java 8 流映射
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Java 8 streams maps with parameters
提问by La Carbonell
I have this couple of functions and I would like to know if it is possible to pass the parameter deviceEvent.hasAlarm()to .map(this::sendSMS)
我有这两个函数，我想知道是否可以将参数传递deviceEvent.hasAlarm()给.map(this::sendSMS)
private void processAlarm (DeviceEvent deviceEvent) {
notificationsWithGuardians.stream()
.filter (notification -> notification.getLevels().contains(deviceEvent.getDeviceMessage().getLevel()))
.map(this::sendSMS)
.map(this::sendEmail);
}
private DeviceAlarmNotification sendSMS (DeviceAlarmNotification notification, DeviceEvent deviceEvent) {
if (deviceEvent.hasAlarm()) {
}
return notification;
}
采纳答案by Andy Turner
Use a lambda instead of the method reference.
使用 lambda 而不是方法引用。
// ...
.map(n -> sendSMS(n, deviceEvent))
// ...
回答by Adrian
... I would like to know if it is possible to pass the parameter
deviceEvent.hasAlarm()tothis::sendSMS
...我想知道是否可以将参数传递
deviceEvent.hasAlarm()给this::sendSMS
No, is not possible. When using method reference you can pass only one argument (docs).
不，不可能。使用方法引用时，您只能传递一个参数 ( docs)。
But from the code you provided there is no need for such thing. Why to check deviceEventfor every notification when it is not changing?
Better way:
但是从您提供的代码来看，不需要这样的东西。为什么在deviceEvent没有变化的情况下检查每个通知？更好的方法：
if(deviceEvent.hasAlarm()) {
notificationsWithGuardians.stream().filter( ...
}
Anyway, if you really want, this can be a solution:
无论如何，如果你真的想要，这可以是一个解决方案：
notificationsWithGuardians.stream()
.filter (notification -> notification.getLevels().contains(deviceEvent.getDeviceMessage().getLevel()))
.map(notification -> Pair.of(notification, deviceEvent))
.peek(this::sendSMS)
.forEach(this::sendEmail);
private void sendSMS(Pair<DeviceAlarmNotification, DeviceEvent> pair) { ... }
回答by dheeraj
How about creating a Class or Member vaiable and assigning value to it and reusing in the reference method provided if reference method is in same class
如果引用方法在同一类中，如何创建一个类或成员变量并为其赋值并在提供的引用方法中重用
