Because a seed_provider can be custom, you can write your own. The only one we ship by default is the SimpleSeedProvided, but you can create your own that say, query some service over the network to get the list of seeds. So the parameters have to be generic for that to work and having the parameters be a Map<String, String> is simple and generic enough.
-- Sylvain On Mon, Oct 31, 2011 at 4:21 AM, Kyle Quest <kcq.li...@gmail.com> wrote: > I noticed a couple of things about the yaml configs in Cassandra: > > seed_provider: > # Addresses of hosts that are deemed contact points. > # Cassandra nodes use this list of hosts to find each other and learn > # the topology of the ring. You must change this if you are running > # multiple nodes! > - class_name: org.apache.cassandra.locator.SimpleSeedProvider > parameters: > # seeds is actually a comma-delimited list of addresses. > # Ex: "<ip1>,<ip2>,<ip3>" > - seeds: "127.0.0.1" <-- question 1 and 2 > > 1. Why use yaml and then resort to manual parsing of the "seeds" > value? Why not let yaml do all of the parsing? > 2. If "parameters" is a map (Map<String, String>) then why use the > "list" notation (dash in front of "seeds"), which really makes > "parameters" a list of maps... The actual Cassandra code then tries to > work around this list of maps behavior by explicitly grabbing the > first element in the list. >
