perf: USE CORRECTLY SIZED STRINGBUILDERS IN GETCLIENTID
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Key: TRINIDAD-887
URL: https://issues.apache.org/jira/browse/TRINIDAD-887
Project: MyFaces Trinidad
Issue Type: Bug
Components: Components
Reporter: Gabrielle Crawford
Assignee: Gabrielle Crawford
Priority: Minor
Explicitly create properly sized stringbuilder in getClientId for perf reasons.
Here's an analysis from a colleague at Oracle:
The Jdev memory profiler reported that after warming up the JVM, each request
of the page from a new browser resulted in about 2.3MB of memory allocated.
About 12% (270K out of total 2324K) of the memory allocated came from the
call org.apache.myfaces.trinidad.component.UIXComponentBase.getClientId.
The code currently does String concatenation, which resulted in an internal
StringBuilder with default length being created:
clientId = (containerComponent.getContainerClientId(context) +
NamingContainer.SEPARATOR_CHAR +
clientId);
The default length is not large enough, so the StringBuilder has to expand,
causing additional memory allocation.
This could be avoided by using a properly-sized StringBuilder:
String cont = containerComponent.getContainerClientId(context);
StringBuilder bld = new StringBuilder(cont.length() + 1 +
clientId.length());
clientId =
bld.append(cont).append(NamingContainer.SEPARATOR_CHAR).append(clientId).toStr
ing();
The code in
org.apache.myfaces.trindad.component.UIXCollection.getContainerClientId has a
similar problem:
if (key != null)
{
id += NamingContainer.SEPARATOR_CHAR + key;
}
A better way to do this would be:
if (key != null)
{
StringBuilder bld = new StringBuilder(id.length() + 1 + key.length());
id =
bld.append(id).append(NamingContainer.SEPARATOR_CHAR).append(key).toString();
}
I tested with the about fix and memory allocated for these two methods
reduced from 270K to 173K, a saving of about 4.2% of total.
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