java - 在 groovy 中应用一些谓词到流过滤器

Question

我在 java 中找到了解决方案的示例:

things.stream()

.过滤( filtersCollection.stream().reduce(Predicate::or).orElse(t->true) )；

我尝试使用 groovy (v2.5.4) 重写它:

List<System> systems = ... //load from db
WellApplicationType appType = params['appType']
Contract contract = params['contract']
List<Predicate> filterCollection = []

if (appType != null)
    filterCollection.add({SystemRunlife systemRl -> systemRl.getApplicationType() == appType })
if (contract != null)
    filterCollection.add({SystemRunlife systemRl -> systemRl.getContract() == contract})

...

systems.stream()
       .map{system -> system.getSystemRunlife()}     
       .filter(filterCollection.stream().reduce{Predicate.&and}.orElse{t -> false})

仅当谓词列表中有 1 个元素时它才有效。如果我有更多，那么我会收到错误:

No signature of method: Script1$_run_closure3$_closure5.doCall() is applicable for argument types: (Script1$_run_closure1, Script1$_run_closure2) values: [Script1$_run_closure1@7d9367fa, Script1$_run_closure2@70c1c430] Possible solutions: doCall(), doCall(java.lang.Object), findAll(), findAll()

谁能告诉我问题出在哪里吗？

更新:

.filter{systemRl -> filterCollection.stream().allMatch{p -> p.test(systemRl)}}

- 也不起作用。

No signature of method: Script1.test() is applicable for argument types: (com.borets.wedb.entity.SystemRunlife) values: [com.borets.wedb.entity.SystemRunlife-5c0d826a-7f63-1ef5-7b74-bde707a1d814 [new]]

Answer 1

Predicate<SystemRunlife> filter = { systemRl -> true }
for (Predicate<SystemRunlife> systemRunlifePredicate : filterCollection) {
    filter = (filter & systemRunlifePredicate)
}

我就是这样组合谓词的。也许有人可以提出更有效的方法。