diff --git a/Documentation/dev-plugins.txt b/Documentation/dev-plugins.txt index 53248c566c..1aeab2c3a3 100644 --- a/Documentation/dev-plugins.txt +++ b/Documentation/dev-plugins.txt @@ -418,6 +418,9 @@ its own custom event class derived from Plugins which define new Events should register them via the `com.google.gerrit.server.events.EventTypes.registerClass()` method. This will make the EventType known to the system. +Deserialzing events with the +`com.google.gerrit.server.events.EventDeserializer` class requires +that the event be registered in EventTypes. [[validation]] == Validation Listeners diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/events/EventDeserializer.java b/gerrit-server/src/main/java/com/google/gerrit/server/events/EventDeserializer.java new file mode 100644 index 0000000000..3508acfd94 --- /dev/null +++ b/gerrit-server/src/main/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. + *

+ * Deserialized objects are of an appropriate subclass based on the value of the + * top-level "type" element. + */ +public class EventDeserializer implements JsonDeserializer { + @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); + } +}