How filter java stream by a list of strings without using a for loop

Question

I have a List<LogEntry> that I need to filter out from the list every log that is not on Level.SEVERE. And in addition I have a List of whitelisted logs that need to be filtered too. These logs are contains only partial message so I have to use contains() to identified them.

My code looks like this:

LogEntries logEntries = driver.manage().logs().get(LogType.BROWSER);
List<LogEntry> logEntriesList = logEntries.getAll();

Stream<LogEntry> filtered =
    logEntriesList.stream()
                  .filter(log -> log.getLevel().equals(Level.SEVERE));
    
for (String whitelisted : whitelistedLogs) {
    filtered = filtered.filter(log -> !log.getMessage().contains(whitelisted));
}

Is there any way to avoid this for loop and get the same result?

I am reverting the edit as the answer need not be posted as part of the question. — Gautham M
– Gautham M, Commented Jun 29, 2021 at 9:11

Gautham M · Accepted Answer · 2021-06-29 09:15:06Z

1

First you filter those with SEVERE log level, then filter those which contains at least one whitelisted message:

logEntriesList.stream()
              .filter(log -> log.getLevel().equals(Level.SEVERE))
              .filter(log -> whitelistedLogs.stream().noneMatch(wl -> log.getMessage().contains(wl)))
              .collect(Collectors.toList());

edited Jun 29, 2021 at 9:15

answered Jun 29, 2021 at 8:08

Gautham M

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3 Comments

Tal Over a year ago

I tried your solution but it didn't worked for me at start, but it gives me a solid direction how to do it. Thanks :)

Gautham M Over a year ago

@Tal you may update the answer here. No need to update the question with the answer.

Gautham M Over a year ago

@Tal Also it is better (more readable) to use noneMatch(condition) instead of allMatch( !condition) I have updated the answer.

Nimantha · Accepted Answer · 2021-07-09 03:41:54Z

0

If whitelisted logs are constant, instead of list, you could create a regex from them one time. That way you could:

filtered = filtered.filter(log -> !log.getMessage().matches(whitelisted_regex));

edited Jul 9, 2021 at 3:41

Nimantha

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answered Jun 29, 2021 at 7:04

user7571491

2 Comments

Tal Over a year ago

I don't think that regex will be helpful in my case. The strings of the whitelisted logs are not related to each other.

user7571491 Over a year ago

If you can give example of whitelisted logs and actual logs, at least few of them, I could try to tell you.

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