Question

如果我正在阅读文件的每一行，如下所示

file.eachLine {line->
println line
}

是否可以读取闭包内的NEXT行。

例如

file.eachLine {line ->
//print next line as well if current line contains 'hooray'
if (line.find(/hooray/)!=null)
{
   println "current line: ${line}"
   println "next line: ${line->next}" //this is just my syntax...
}
}

Answer 1

封闭没有直接支持，但如果你稍微改变一下，它很容易实现相同的逻辑：

// test script:
def f = new File("test.txt")
def currentLine
f.eachLine { nextLine ->
    if (currentLine) {
        if (currentLine.find(/hooray/)) {
            println "current line: ${currentLine}"
            println "next line: ${nextLine}"
        }    
    }    
    currentLine = nextLine
}


// test.txt contents:
first line
second line
third line
fourth line
fifth hooray line 
sixth line
seventh line

编辑：

如果您正在寻找Chili在下面评论过的封装，您可以随时在File上定义自己的方法：

File.metaClass.eachLineWithNextLinePeek = { closure ->
    def currentLine
    delegate.eachLine { nextLine ->
        if (currentLine) {
            closure(currentLine, nextLine) 
        }
        currentLine = nextLine
    }
}

def f = new File("test.txt")
f.eachLineWithNextLinePeek { currentLine, nextLine ->
    if (currentLine.find(/hooray/)) {
        println "current line: ${currentLine}"
        println "next line: ${nextLine}"
     }
}

groovy闭包变量增量

1 个答案: