[jira] [Created] (MIME4J-302) MessageBuilder::parse repeatedly calls toLowerCase on header names

["Benoit Tellier (Jira)" <mi...@james.apache.org>]

Benoit Tellier created MIME4J-302:
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             Summary: MessageBuilder::parse repeatedly calls toLowerCase on header names
                 Key: MIME4J-302
                 URL: https://issues.apache.org/jira/browse/MIME4J-302
             Project: James Mime4j
          Issue Type: Improvement
          Components: core, dom
            Reporter: Benoit Tellier


As attached I was surprised MIME4J parsing spends 18% of its time calling toLowerCase on header names. This represents 12% of allocated memory.

By holding the lowerCased name as part of the field name, and doing lazy initialization on it we can get this down to 6%.

Also, an optimization implemented in MaximalBodyDescriptor aims at reducing the costs of toLowerCase calls: upon known header names lookup the lowercase version of the field instead of the normal version to benefit optimizations (calling toLowerCase on a lowerCase string do not do allocation, it just iterates String content). It might be worth generalizing it.



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