將迭代器代碼轉換爲流

轉換此嵌套迭代正在吹我的腦海有人可以將其轉換爲並行流嗎？我希望能夠檢查與我的每位客戶團隊成員的標準相符的分配。我剛剛切換到了Java 8，並且正在努力圍繞利用並行流來完成此聚合的最佳方式。將迭代器代碼轉換爲流

for(Iterator<BasicDBObject> iterator = members.iterator(); iterator.hasNext();) { 
    BasicDBObject member = iterator.next(); 

    //if the member doesn't have a valid assignment remove them. 
    boolean memberContainsValidAssignment = false; 

    BasicDBObject role = member.get("accountTeamRole") == null ? null : (BasicDBObject) member.get("accountTeamRole"); 
    if (accTeamRoleCodes != null && !accTeamRoleCodes.contains(role.get("code"))) { 
     iterator.remove(); 
     continue; 
    } 

    List<BasicDBObject> assignments = member.get("assignments") == null ? new ArrayList<>() : (List) member.get("assignments"); 
    for (Iterator<BasicDBObject> assignIterator = assignments.iterator(); assignIterator.hasNext();) { 
     BasicDBObject assignment = assignIterator.next(); 

     Date endDate = (Date) assignment.get("assignmentValidToDate"); 
     Date startDate = (Date) assignment.get("assignmentValidFromDate"); 

     if(startDate == null){//this is junk, should have never been allowed. 
      LOGGER.warn("There's no start date for this assignment. {}", assignment.toString()); 
      assignIterator.remove(); 
      continue; 
     } 
     //1. open ended assignment, it lives on forever. 2.falls in between active date. 
     else if(endDate == null ||(activeDate.after(startDate) && activeDate.before(endDate))){ 
      LOGGER.debug("adding an assignment. {}", assignment.toString()); 
      memberContainsValidAssignment = true; 
      convertDatesToString(assignment); 
      continue; 
     } 

    } 
    if(!memberContainsValidAssignment){ 
     iterator.remove(); 
    } 
}

來源

2015-09-04 Christopher Nolan Buckley

流不會讓你從底層集合中刪除任何東西。 –

如何根據相同的標準制作新清單？我遇到的問題是三元操作和if語句。也不知道我怎麼會去做像調用轉換日期.. –

國際海事組織，你的代碼看起來很好，因爲它是。我認爲這不是Streams的任務。 – Tunaki

下面是將您的代碼轉換爲使用流的一個鏡頭。請檢查過濾條件的細節。

List<BasicDBObject> invalidAssignments = members.stream() 
     .filter(member -> accTeamRoleCodes == null || 
          member.get("accountTeamRole") == null || 
          accTeamRoleCodes.contains(member.get("accountTeamRole").get("code")) 
       ) 
     .flatMap(member -> member.get("assignments").stream()) 
     .filter(assignment -> (Date) assignment.get("assignmentValidFromDate") != null && 
           ((Date) assignment.get("assignmentValidToDate") != null || 
           (activeDate.after((Date)assignment.get("assignmentValidFromDate")) && 
           activeDate.before((Date)assignment.get("assignmentValidToDate")))) 
       ) 
     .collect(Collectors.toList());

爲了使平行的東西也只是用members.parallelStream代替members.stream的問題。

來源

2015-09-04 22:25:55 rrufai

將迭代器代碼轉換爲流

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