即使不存在匹配项，Java 正则表达式负前瞻也会返回匹配项

Question

I have a string as follows:

<marker name="my.marker" cachedBy="all" affectedBy="typ1,type2">
<child1>bla</child1>
</marker>

What I would like to do is a lookup to identify the first occurrence of > using the following condition.

1. Match > if the line doesn't have affectedBy= attribute available eg affectedBy="type1" . Because I would like to append it to that line. So I don't want it to be duplicated eg affectedBy="type1,type2", affectedBy="type1,type2"

2. Match only the firs occurrence of > - ie not a global match.

I tried the following:

<(?!=(.*sharedBy=".*"))>

But it returns a match for > even when affectedBy= is present. I am sure this might be something wrong in my lookahead logic, but cannot figure it out. Any help would be appreciated.

Answer 1

I simply did the following:

1) If anything Matches affectedBy=.*> ignore it.

2) Otherwise, find the first group matching (?=<marker name="my.marker".*)?> , and then replace > with affectedBy="type1,type2>"

Didn't want to write XML parsing.