Java Object Semantics
1. Objects will not be re-instantiated/rebuilt unless they have internal Collection}}s to which they add through and {{add_X_ method. If you have data structures such as as Map, the map will not be cleared or reconstructed on multiple calls to execute the containing task (i.e., inside a loop).
2. If you have implemented an add_X_ or set_X_ method which takes a field of the parameter object and uses it as a key to an internal map, be careful of the situation in which that field may change (under looping conditions where its value references the environment). For instance:
<for var="i" from="0" to="${max}">
<declare name="filter" global="true">
<local-event-filter topic="TROLL-${i}">
<event-header-comparator>
<property-comparator comparator="EQUALS">
<property name="component-${i}">
<value>master</value>
</property>
</property-comparator>
</event-header-comparator>
</local-event-filter>
</declare>
</for>
It so happens that the <property-comparator>'s method for adding properties takes the property name and uses it as a key to an internal map (e.g., {p.name=p}). This means that the comparator instance (which is static), will have a property with an updated name in the map on each call, but the key will always be component-0. The suggested solution here is to use new:
<for var="i" from="0" to="${max}">
<declare name="filter" global="true">
<new>
<local-event-filter topic="TROLL-${i}">
<event-header-comparator>
<property-comparator comparator="EQUALS">
<property name="component-${i}">
<value>master</value>
</property>
</property-comparator>
</event-header-comparator>
</local-event-filter>
</new>
</declare>
</for>