Namespaces
With more traits and different services, as well as with the number of stages growing the need to organize stages has come. Traditionally the whole benchmark was covered with one XML schema, stages using prefixes or postfixes to describe their target traits without any strict concept.
Plugins and reporters already use their XML schemas for configuration of services, and using XML namespaces is the XML-natural way to organize stages, too.
When XML schemas are generated, these all should end up in distribution directory in the schema/ subdirectory. For convenience, there’s a directory symlink schema in root project directory that points to this directory so that IDE can recognize the generated XSD as source.
Essential namespaces
The root benchmark namespace is urn:radargun:benchmark:VERSION, with benchmark as the root element. This contains the main, cluster, configuration, init, scenario, destroy, cleanup and reports elements. Actually, the init, destroy and cleanup elements extend a type defined in the urn:radargun:stages:core:VERSION namespace, that contains all the basic stages not specific to particular service type, e.g. those related to service lifecycle, monitoring etc. Note that cache-like traits living in core in the past have been moved to separate module, extensions/cache.
When the benchmark does not contain the scenario directly but instead imports another file using <scenario url="..."<, the target file should use the urn:radargun:scenario:VERSION namespace which has scenario as a root element.
Although you can use any namespace prefix, the convention is to use prefix rg for both urn:radargun:benchmark:VERSION and urn:radargun:scenario:VERSION since these two won’t end up in the same file and describe similar elements (most notably the repeat element), and prefix core for namespace urn:radargun:stages:core:VERSION.
Extension namespaces
Stages from each module end up by default in the module namespace that is urn:radargun:stages:MODULE:VERSION, e.g. urn:radargun:stages:cache:3.0 for the radargun-cache module. When it is desired to use multiple namespaces within one module, stage class can be annotated with @Namespace annotation. The value of the annotation is the full namespace name, e.g. @Namespace("urn:radargun:stages:foo:3.0") (it is possible to have namespace without the urn:radargun:stages prefix, although it is not recommended). In the future, we plan to add an option to set namespace for whole package in package-info.java, but this is not implemented so far.
The stage name should not contain the module name anymore - for example the stage CacheClearStage has been renamed to ClearStage and in the benchmark file it is used as <cache:clear .../< instead of <cache-clear .../<. Note the use of prefix cache; you can use xmlns:xxx="urn:radargun:stages:cache:3.0 as well, but using module name as the prefix is the most readable.
Map-Reduce, Distributed Execution and Streams ended up in the cache module as caches are currently the only services that implement these traits. In future, the stages can be moved to their own extension modules.