含糊不清的groovy:如何解决

Question

我试图在groovy中这样做

def results = new File(someDirectory).listFiles { it.name.startsWith 'foo'}

但是,我得到了可以理解的错误:

groovy.lang.GroovyRuntimeException: Ambiguous method overloading for method java.io.File#listFiles.
Cannot resolve which method to invoke for [class change$_getRollback_closure1] due to overlapping prototypes between:
    [interface java.io.FileFilter]
    [interface java.io.FilenameFilter]

我如何告诉它使用FileFilter？

我最后写了一些简单的java风格:

File[] files = someDir.listFiles( new FileFilter(){
    @Override
    boolean accept(File pathname) {
        return pathname.name.startsWith("foo")
    }
})

Answer 1

您可以强制转换或强制关闭以指定您所指的SAM类型/功能接口.

// using a typecast:
def results = new File(someDirectory).listFiles((FileFilter) { it.name.startsWith 'foo'})

// using as keyword:
def results = new File(someDirectory).listFiles({ it.name.startsWith 'foo'} as FileFilter)

// using SAM-type coercion:
FileFilter ff = { it.name.startsWith 'foo'}
def results = new File(someDirectory).listFiles(ff)