英文:
Java 11 Lambda - check each object, return true when the first condition is met, else return false
问题
我有一个运行良好的方法。它的外观如下。
private boolean roomWithMoreThanTenFurnitures(Building building) {
if (building != null && building.hasRooms()) {
for (Room room : building.getRooms()) {
if (room.getFurnitures().size() > 10) {
return true;
}
}
}
return false;
}
我想将其转换为Lambda表达式。我已经创建了外壳，但不确定如何在if (condition)之后填入return true或在外部填入return false。
building.getRooms().forEach(room -> {
// ??
});
英文:
I have a method that works fine. This is how it looks.
private boolean roomWithMoreThanTenFurnitures(Building building) {
if (building != null && building.hasRooms()) {
for (Room room : building.getRooms()) {
if (room.getFurnitures.size() > 10) {
return true;
}
}
}
return false;
}
I wanna switch this to Lambda. In came uo with the shell, but I am not sure how fill in the if (condition) return true or return false outside.
building.getRooms().forEach(room -> {
//??
});
答案1
得分: 5
你不能用这种方式做 - foreach 用于对集合/流元素执行某些操作，而不是用于筛选它们或映射到结果。
你需要使用例如 anyMatch 方法 - 例如：
building.getRooms().stream().anyMatch(room -> room.getFurnitures().size() > 10)
英文:
You cannot do it this way - the foreach is for executing some action for every of the collection/stream element not for filtering them or mapping to a result
You need e.g. anyMatch method - for example
building.getRooms().stream().anyMatch(room -> room.getFurnitures.size() > 10)
答案2
得分: 0
你可以这样做。根据初始条件返回false，然后对房间进行流处理。这假设房间可以被流式处理（例如一个列表）。如果它们是数组，你需要类似这样的操作：Arrays.stream(building.getRooms())
private boolean roomWithMoreThanTenFurnitures(Building building) {
if (building != null && building.hasRooms()) {
return building.getRooms().stream()
.anyMatch(room -> room.getFurnitures.size() > 10);
}
return false;
}
英文:
You can do it like this. Returns false based on the initial conditions, then streams the rooms. This presumes the rooms can be streamed (e.g a List). If they are an array you will need to do something similar to Arrays.stream(building.getRooms())
private boolean roomWithMoreThanTenFurnitures(Building building) {
if (building != null && building.hasRooms()) {
return building.getRooms().stream()
.anyMatch(room -> room.getFurnitures.size() > 10);
}
return false;
}
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