/**
* instantiate a strategy from a config property. requires conf to have already been set (as well
* as anything the provider might need to read).
*/
RegionGroupingStrategy getStrategy(
final Configuration conf, final String key, final String defaultValue) throws IOException {
Class<? extends RegionGroupingStrategy> clazz;
try {
clazz = Strategies.valueOf(conf.get(key, defaultValue)).clazz;
} catch (IllegalArgumentException exception) {
// Fall back to them specifying a class name
// Note that the passed default class shouldn't actually be used, since the above only fails
// when there is a config value present.
clazz = conf.getClass(key, IdentityGroupingStrategy.class, RegionGroupingStrategy.class);
}
LOG.info("Instantiating RegionGroupingStrategy of type " + clazz);
try {
final RegionGroupingStrategy result = clazz.newInstance();
result.init(conf);
return result;
} catch (InstantiationException exception) {
LOG.error(
"couldn't set up region grouping strategy, check config key " + REGION_GROUPING_STRATEGY);
LOG.debug("Exception details for failure to load region grouping strategy.", exception);
throw new IOException("couldn't set up region grouping strategy", exception);
} catch (IllegalAccessException exception) {
LOG.error(
"couldn't set up region grouping strategy, check config key " + REGION_GROUPING_STRATEGY);
LOG.debug("Exception details for failure to load region grouping strategy.", exception);
throw new IOException("couldn't set up region grouping strategy", exception);
}
}
