From f9adf50cbcf06c260e71e3fbe157cd1e01f7d59e Mon Sep 17 00:00:00 2001
From: Arto Bendiken <arto@bendiken.net>
Date: Sun, 12 Dec 2010 02:50:08 +0100
Subject: [PATCH] Implemented the RDF::Query#optimize and #optimize! methods.

---
 lib/rdf/query.rb | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/lib/rdf/query.rb b/lib/rdf/query.rb
index 42745b02..11eeab7f 100644
--- a/lib/rdf/query.rb
+++ b/lib/rdf/query.rb
@@ -153,6 +153,33 @@ def pattern(pattern, options = {})
       self
     end
 
+    ##
+    # Returns an optimized copy of this query.
+    #
+    # @param  [Hash{Symbol => Object}] options
+    #   any additional options for optimization
+    # @return [RDF::Query] a copy of `self`
+    # @since  0.3.0
+    def optimize(options = {})
+      self.dup.optimize!(options)
+    end
+
+    ##
+    # Optimizes this query by reordering its constituent triple patterns
+    # according to their cost estimates.
+    #
+    # @param  [Hash{Symbol => Object}] options
+    #   any additional options for optimization
+    # @return [void] `self`
+    # @see    RDF::Query::Pattern#cost
+    # @since  0.3.0
+    def optimize!(options = {})
+      @patterns.sort! do |a, b|
+        (a.cost || 0) <=> (b.cost || 0)
+      end
+      self
+    end
+
     ##
     # Executes this query on the given `queryable` graph or repository.
     #