Added deserialization helpers for List and Map

Author: JanHolger

src/main/java/org/javawebstack/graph/util/GsonListDeserializer.java

@@ -0,0 +1,21 @@
+package org.javawebstack.graph.util;
+
+import com.google.gson.*;
+
+import java.lang.reflect.Type;
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class GsonListDeserializer<T> implements JsonDeserializer<List<T>> {
+    protected abstract Class<T> getType();
+    public List<T> deserialize(JsonElement json, Type type, JsonDeserializationContext deserializationContext) throws JsonParseException {
+        if(json == null || !json.isJsonArray())
+            return null;
+        JsonArray jsonArray = json.getAsJsonArray();
+        List<T> list = new ArrayList<>();
+        Class<?> t = getType();
+        for(JsonElement e : jsonArray)
+            list.add(deserializationContext.deserialize(e, t));
+        return list;
+    }
+}

src/main/java/org/javawebstack/graph/util/GsonMapDeserializer.java

@@ -0,0 +1,21 @@
+package org.javawebstack.graph.util;
+
+import com.google.gson.*;
+
+import java.lang.reflect.Type;
+import java.util.HashMap;
+import java.util.Map;
+
+public abstract class GsonMapDeserializer<T> implements JsonDeserializer<Map<String,T>> {
+    protected abstract Class<T> getType();
+    public Map<String, T> deserialize(JsonElement json, Type type, JsonDeserializationContext deserializationContext) throws JsonParseException {
+        if(json == null || !json.isJsonObject())
+            return null;
+        JsonObject jsonObject = json.getAsJsonObject();
+        Map<String, T> map = new HashMap<>();
+        Class<?> t = getType();
+        for(String k : jsonObject.keySet())
+            map.put(k, deserializationContext.deserialize(jsonObject.get(k), t));
+        return map;
+    }
+}