1 files changed, 19 insertions, 0 deletions
diff --git a/lib/rubygems/resolver/composed_set.rb b/lib/rubygems/resolver/composed_set.rb
index e4aa15e4d0..702bd9ccfc 100644
--- a/lib/rubygems/resolver/composed_set.rb
+++ b/lib/rubygems/resolver/composed_set.rb
@@ -1,17 +1,36 @@
+##
+# A ComposedSet allows multiple sets to be queried like a single set.
+#
+# To create a composed set with any number of sets use:
+#
+#   Gem::Resolver.compose_sets set1, set2
+#
+# This method will eliminate nesting of composed sets.
+
 class Gem::Resolver::ComposedSet < Gem::Resolver::Set
 
   attr_reader :sets # :nodoc:
 
+  ##
+  # Creates a new ComposedSet containing +sets+.  Use
+  # Gem::Resolver::compose_sets instead.
+
   def initialize *sets
     @sets = sets
   end
 
+  ##
+  # Finds all specs matching +req+ in all sets.
+
   def find_all req
     res = []
     @sets.each { |s| res += s.find_all(req) }
     res
   end
 
+  ##
+  # Prefetches +reqs+ in all sets.
+
   def prefetch reqs
     @sets.each { |s| s.prefetch(reqs) }
   end