Initial transaction support

ChangeLog.md

@@ -1,5 +1,13 @@
 ## Changes between Titanium 1.0.0-alpha1 and 1.0.0-alpha2
 
+### Transaction Control Functions
+
+`clojurewerkz.titanium.graph/commit-tx!` and `clojurewerkz.titanium.graph/rollback-tx!`
+commit and roll back current transaction, respectively. Note that closing a
+graph will automatically commit current transaction. Every operation
+that modifies the graph will automatically start a transaction if needed.
+
+
 ### clojurewerkz.titanium.graph/get-vertices Now Accepts Keywords For Keys
 
 `clojurewerkz.titanium.graph/get-vertices` now accepts keywords for keys,

src/clojure/clojurewerkz/titanium/graph.clj

@@ -1,7 +1,9 @@
 (ns clojurewerkz.titanium.graph
   (:require [clojurewerkz.titanium.elements :as te])
   (:import [com.thinkaurelius.titan.core TitanFactory TitanGraph]
-           [com.tinkerpop.blueprints Graph KeyIndexableGraph Vertex Edge]))
+           [com.tinkerpop.blueprints Vertex Edge
+            Graph KeyIndexableGraph
+            TransactionalGraph TransactionalGraph$Conclusion]))
 
 
 ;;
@@ -139,3 +141,18 @@
 (defn deindex-edges-by-key!
   [^KeyIndexableGraph g ^String k]
   (.dropKeyIndex g k com.tinkerpop.blueprints.Edge))
+
+
+;;
+;; Transactions
+;;
+
+(defn commit-tx!
+  "Commits current transaction"
+  [^TransactionalGraph g]
+  (.stopTransaction g TransactionalGraph$Conclusion/SUCCESS))
+
+(defn rollback-tx!
+  "Rolls back current transaction"
+  [^TransactionalGraph g]
+  (.stopTransaction g TransactionalGraph$Conclusion/FAILURE))

test/clojurewerkz/titanium/graph_test.clj

@@ -127,3 +127,22 @@
         m2 {"station" "Northfields"  "lines" #{"Piccadilly"}}]
     (tg/populate g
                  (m1 -links-> m2))))
+
+
+;;
+;; Transactions
+;;
+
+(deftest test-very-basic-transaction-that-is-committed
+  (let [g   (tg/open-in-memory-graph)
+        v1  (tg/add-vertex g {})
+        v2  (tg/add-vertex g {})]
+    (tg/commit-tx! g)
+    (tg/close g)))
+
+(deftest test-very-basic-transaction-that-is-rolled-back
+  (let [g   (tg/open (System/getProperty "java.io.tmpdir"))
+        v1  (tg/add-vertex g {})
+        v2  (tg/add-vertex g {})]
+    (tg/rollback-tx! g)
+    (tg/close g)))