Some iteration to resolve problems encountered in the project

1. // iteration delete () ... () ... ()

def parseTail(sqlContext: String): String = {

  val pre = sqlContext.indexOf("(")
  val end = sqlContext.indexOf(")")

  if(pre == -1 && end == -1)
    return sqlContext

  parseTail(sqlContext.substring(0, pre) + sqlContext.substring(end + 1))
}

parseTail(sql)

　　

 

2. Remove iteration // (.. (..) ..) .. (..) n-weight nested structure

// 迭代计算 ( 个数
def parseIndexNum(s: String): Int = {
  if (s.indexOf("(") > s.indexOf(")") || s.indexOf("(") == -1) return 0
  return parseIndexNum(s.substring(s.indexOf("(") + 1)) + 1
}


// 迭代删除 ()...()...()
def parseTail(sqlContext: String): String = {

  val pre = sqlContext.indexOf("(")
  var end = sqlContext.indexOf(")")

  if (pre == -1 || end == -1)
    return sqlContext

  var sqlCopy = sqlContext
  val pre_count = parseIndexNum(sqlContext)

  if (pre_count > 1) {
    (0 until pre_count - 1).foreach(_ => {
      val index = sqlCopy.indexOf(")")
      sqlCopy = sqlCopy.substring(0, index) + "w" + sqlCopy.substring(index + 1)
    })
    end = sqlCopy.indexOf(")")
  }
  parseTail(sqlContext.substring(0, pre) + sqlContext.substring(end + 1))

}