10.2. Eviction Regions

The concept of regions and the Region class were Section 7.6, “Class Loading and Regions” when talking about marshalling. Regions are also used to define the eviction behavior for nodes within that region. In addition to using a region-specific configuration, you can also configure default, cache-wide eviction behavior for nodes that do not fall into predefined regions or if you do not wish to define specific regions. It is important to note that when defining regions using the configuration XML file, all elements of the Fqn that defines the region are String objects.

For each region, you can define eviction parameters.

It's possible to define regions that overlap. In other words, one region can be defined for /a/b/c, and another defined for /a/b/c/d (which is just the d subtree of the /a/b/c sub-tree). The algorithm, in order to handle scenarios like this consistently, will always choose the first region it encounters. In this way, if the algorithm needed to decide how to handle node /a/b/c/d/e, it would start from there and work its way up the tree until it hits the first defined region - in this case /a/b/c/d.

...
   Map lotsOfData = generateData();
   cache.put("/a/b/c", lotsOfData);
   cache.getRoot().getChild("/a").setResident(true);
   cache.getRoot().getChild("/a/b").setResident(true);
...

...
   Map lotsOfData = generateData();
   cache.put("/a/b/c", lotsOfData);
   cache.getRoot().getChild("/a").setResident(true);
   cache.getRoot().getChild("/a/b").setResident(true);
...