some refactor of the code

lib/polecat/index_writer.rb

@@ -52,11 +52,58 @@ class Polecat
     # Write all stored documents to the disc and clear the buffer.
     # @return [Boolean] true when the write was a success
     def write
-      lock_path = @path + '/index.lock'
-      if File.exists?(lock_path)
-        return false
+      return false unless set_lock
+      file_name = generate_filename
+              
+      File.open file_name, 'w' do |file|
+        file.write Marshal.dump(@documents)
+      end
+
+      @documents = []
+      release_lock
+    end
+
+    # creates an index reader with the writers path
+    #
+    # @returns [Polecat::IndexReader] an IndexReader with the same path
+    def create_reader
+      Polecat::IndexReader.new @path
+    end
+
+    # set the lock on the index
+    # @private
+    def set_lock
+      if File.exists? lock_file_name
+        false
       else
-        FileUtils.touch(lock_path)
+        FileUtils.touch lock_file_name
+        true
+      end
+    end
+    private :set_lock
+
+    # release the index lock
+    # @private
+    def release_lock
+      if File.exists? lock_file_name
+        FileUtils.rm lock_file_name
+        true
+      else
+        false
+      end
+    end
+    private :release_lock
+
+    # get the full path of the lock file
+    # @private
+    def lock_file_name
+      @path + '/index.lock'
+    end
+    private :lock_file_name
+
+    # generates a new file name for an index file
+    # @private
+    def generate_filename 
       last_file = Dir[@path + '/*.ind'].sort.last
       if last_file.nil?
         file_name = @path + '/ind0.ind'
@@ -69,22 +116,8 @@ class Polecat
           "ind#{(number + 1)}.ind"
         )
       end
-        
-        File.open file_name, 'w' do |file|
-          file.write Marshal.dump(@documents)
-        end
-
-        @documents = []
-        FileUtils.rm lock_path
-        return true
-      end
-    end
-
-    # creates an index reader with the writers path
-    #
-    # @returns [Polecat::IndexReader] an IndexReader with the same path
-    def create_reader
-      Polecat::IndexReader.new @path
+      file_name
     end
+    private :generate_filename
   end
 end