[XMLBEANS-389] List accessors generated with -javasource=1.5 produce lists that scale poorly with the size of the list

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: Version 2, Version 2.1, Version 2.2, Version 2.2.1, Version 2.3, Version 2.3.1, Version 2.4 , Version 2.4.1
• Component/s: Compiler
• Assignee: Unassigned
• Reporter: Philip Aston
• Created: 13/Nov/08 13:19
• Updated: 20/Sep/11 20:57

Description

When a schema is compiled with -javasource=1.5, convenient list based accessors are generated as well as the array accessors. E.g.

java.util.List<java.lang.String> getParamList()

The implementation of the List is built upon java.lang.AbstractList. The AbstractList iterator's hasNext() method calls size(). For an XMLBean generated list, size() walks the store and so iteration scales quadratically.

Here are some numbers showing the problem:

XMLBeans backed list of 1 strings: 0.013766 ms
XMLBeans backed list of 16 strings: 0.255458 ms
XMLBeans backed list of 256 strings: 1.612057 ms
XMLBeans backed list of 1024 strings: 25.458934 ms
XMLBeans backed list of 2048 strings: 123.393447 ms
XMLBeans backed list of 4096 strings: 505.594661 ms
plain list of 1 strings: 0.002304 ms
plain list of 16 strings: 0.007788 ms
plain list of 256 strings: 0.013384 ms
plain list of 1024 strings: 0.052215 ms
plain list of 2048 strings: 0.103550 ms
plain list of 4096 strings: 0.206648 ms

I think the generated list should override iterator(), and return an Iterator that calculates the list size once per iteration.