Hubert Law created AUTOTAG-24:
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Summary: Efficiency of regular expression under
AbstractModelBody.evaluateAsString
Key: AUTOTAG-24
URL: https://issues.apache.org/jira/browse/AUTOTAG-24
Project: Tiles Autotag
Issue Type: Improvement
Affects Versions: 1.2.0
Reporter: Hubert Law
Despite AUTOTAG-21 the regex still eats up CPU time due to the inefficiency of
the pattern {{s*$}} which, in case of long consecutive white-space in the
middle of the body, consumes O(n^2^) time while failing to match (since it will
attempt to start matching at each white space position).
Matching the actual non-whitespace content directly may be more efficient in
this case, e.g
{{private static final Pattern PATTERN =
Pattern.compile("^\\s*(\\S(?:.*\\S)?)\\s*$");}}
{{if (body != null) {}}
{{ final Matcher matcher = PATTERN.matcher(body);}}
{{ if (matcher.matches()) {}}
{{ body = matcher.group(1);}}
{{ } else {}}
{{ body = null;}}
{{ } }}
{{}}}
Backtracking is limited to the final white spaces, in linear time.
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