Description Alex Sanielevici 2005-08-01 15:43:49 EDT

The symptoms described here are similar to those of 84103, but this is not a 
duplicate.

The Feature JAR and Plugin JARs are fetched from the HTTP server exactly twice 
during a successful update operation triggered using the standalone API's 
UpdateCommand class, with any feature (for which update is available) given as 
parameter. 

Sample output from HTTP access log during a successful update:

127.0.0.1 - - [01/Aug/2005:13:58:37 -
0400] "GET /update/TestUpdate/features/Test_Feature_1.5.4.jar HTTP/1.1" 200 599
127.0.0.1 - - [01/Aug/2005:13:58:37 -
0400] "GET /update/TestUpdate/features/Test_Feature_1.5.4.jar HTTP/1.1" 200 599
127.0.0.1 - - [01/Aug/2005:13:58:37 -
0400] "GET /update/TestUpdate/plugins/com.test.plugin_1.5.4.jar HTTP/1.1" 200 
391756
127.0.0.1 - - [01/Aug/2005:13:58:38 -
0400] "GET /update/TestUpdate/plugins/com.test.plugin_1.5.4.jar HTTP/1.1" 200 
391756


My initial analysis, if it helps: From stepping through the debugger while 
following the access log with tail -f, I've found that for each update found 
by the update search, OperationFactory’s createInstallOperation() is called, 
which fetches the feature JAR for the first time.

These install operations are collected into a BatchInstallOperation and then 
executed. During the execution, Feature.install() calls 
FeaturePackagedContentProvider.getFeatureEntryArchiveReferences(), which calls 
asLocalReference() and results in a re-downloading the feature JAR. Perhaps 
this can be avoided if the file were to be placed in the local cache, which 
this method checks with a call to Utilities.lookupLocalFile(key);

As for the plugin JAR getting retrieved twice: the first time is 
Feature.install() -> getPluginEntryArchiveReferences() -> asLocalReference() 
resulting in a download. Then, in the loop where the files contained in the 
plugin JAR are stored, the first iteration is what *seems* to result in a re-
download of the plugin JAR. I haven't been able to pinpoint why, so it may be 
something in another thread doing this.

for (int j = 0; j < references.length; j++) {
    setMonitorTaskName(
		subMonitor,
		msg + references[j].getIdentifier());
    pluginConsumer.store(references[j], subMonitor);
}