1 files changed, 49 insertions, 0 deletions
diff --git a/java/com/google/gerrit/server/events/EventDeserializer.java b/java/com/google/gerrit/server/events/EventDeserializer.java
new file mode 100644
index 0000000000..2a7eada646
--- /dev/null
+++ b/java/com/google/gerrit/server/events/EventDeserializer.java
@@ -0,0 +1,49 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.events;
+
+import com.google.gson.JsonDeserializationContext;
+import com.google.gson.JsonDeserializer;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonParseException;
+import java.lang.reflect.Type;
+
+/**
+ * JSON deserializer for {@link Event}s.
+ *
+ * <p>Deserialized objects are of an appropriate subclass based on the value of the top-level "type"
+ * element.
+ */
+public class EventDeserializer implements JsonDeserializer<Event> {
+  @Override
+  public Event deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
+      throws JsonParseException {
+    if (!json.isJsonObject()) {
+      throw new JsonParseException("Not an object");
+    }
+    JsonElement typeJson = json.getAsJsonObject().get("type");
+    if (typeJson == null
+        || !typeJson.isJsonPrimitive()
+        || !typeJson.getAsJsonPrimitive().isString()) {
+      throw new JsonParseException("Type is not a string: " + typeJson);
+    }
+    String type = typeJson.getAsJsonPrimitive().getAsString();
+    Class<?> cls = EventTypes.getClass(type);
+    if (cls == null) {
+      throw new JsonParseException("Unknown event type: " + type);
+    }
+    return context.deserialize(json, cls);
+  }
+}