diff --git a/src/main/java/org/bdware/mockjava/MockGenerator.java b/src/main/java/org/bdware/mockjava/MockGenerator.java
index bca5542..33190ee 100644
--- a/src/main/java/org/bdware/mockjava/MockGenerator.java
+++ b/src/main/java/org/bdware/mockjava/MockGenerator.java
@@ -4,16 +4,32 @@ import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonPrimitive;
-import org.bdware.mockjava.generator.IntegerGenerator;
+import org.bdware.mockjava.generator.Generator;
+
+import java.util.HashMap;
+import java.util.Map;
 
 public class MockGenerator extends JsonVisitor {
-    public static MockGenerator instance = new MockGenerator();
-    JsonElement result;
 
+    public static MockGenerator instance = new MockGenerator();
+    Map<String,ValueGenerator> prefixToGenerator;
+    JsonElement result;
     public JsonElement get() {
         return result;
     }
-
+    public  MockGenerator(Class ...clzs){
+        prefixToGenerator = new HashMap<>();
+        for (Class clz:clzs){
+            Generator generator =(Generator) clz.getAnnotation(Generator.class);
+            if (generator!=null){
+                try {
+                    prefixToGenerator.put(generator.tag(),(ValueGenerator)clz.getConstructor().newInstance());
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
     @Override
     public JsonVisitor visitObject(JsonObject jsonObject) {
         JsonObject jo = new JsonObject();
@@ -44,9 +60,8 @@ public class MockGenerator extends JsonVisitor {
     @Override
     public JsonVisitor visitPrimitive(JsonPrimitive primitive) {
         if (!primitive.isString()) result = primitive.deepCopy();
-
         ValueGenerator generator = lookupGenerator(primitive.getAsString());
-        result = generator.generate(null, primitive);
+        result = generator.generate( primitive);
         return this;
     }
 
@@ -54,18 +69,22 @@ public class MockGenerator extends JsonVisitor {
         if (!str.startsWith("@")) {
             return new ValueGenerator() {
                 @Override
-                public JsonElement generate(String preField, JsonElement previous) {
+                public JsonElement generate(  JsonElement previous) {
                     return new JsonPrimitive(str);
                 }
             };
         }
-        String[] args = null;
         int from = str.indexOf("(");
-        if (from != -1) {
-            int to = str.indexOf(")");
-            String subStr = str.substring(from + 1, to);
-            args = subStr.split(",");
+        String prefix = from>=0?str.substring(0,from):str;
+        ValueGenerator generator  = prefixToGenerator.get(prefix);
+        if (generator==null){
+            return new ValueGenerator() {
+                @Override
+                public JsonElement generate(JsonElement previous) {
+                    return new JsonPrimitive("unknown type, prefix:"+prefix+" all:"+str);
+                }
+            };
         }
-        return IntegerGenerator.create(args);
+        return generator;
     }
 }
diff --git a/src/main/java/org/bdware/mockjava/ValueGenerator.java b/src/main/java/org/bdware/mockjava/ValueGenerator.java
index aabb66c..0e89460 100644
--- a/src/main/java/org/bdware/mockjava/ValueGenerator.java
+++ b/src/main/java/org/bdware/mockjava/ValueGenerator.java
@@ -3,5 +3,5 @@ package org.bdware.mockjava;
 import com.google.gson.JsonElement;
 
 public abstract class ValueGenerator {
-    public abstract JsonElement generate(String preField,JsonElement previous);
+    public abstract JsonElement generate(JsonElement previous);
 }
diff --git a/src/main/java/org/bdware/mockjava/generator/IntegerGenerator.java b/src/main/java/org/bdware/mockjava/generator/IntegerGenerator.java
index 09921f4..3900a32 100644
--- a/src/main/java/org/bdware/mockjava/generator/IntegerGenerator.java
+++ b/src/main/java/org/bdware/mockjava/generator/IntegerGenerator.java
@@ -9,15 +9,11 @@ import java.util.Random;
 
 @Generator(tag = "@integer")
 public class IntegerGenerator extends ValueGenerator {
-    // TODO
-    public static IntegerGenerator create(String[] args) {
-        return new IntegerGenerator();
-    }
-
-    static Random secureRandom = new SecureRandom();
-
+    public IntegerGenerator(){}
+     static Random secureRandom = new SecureRandom();
     @Override
-    public JsonElement generate(String preField, JsonElement previous) {
+    public JsonElement generate(JsonElement previous) {
+        // TODO parse value here
         return new JsonPrimitive(secureRandom.nextInt());
     }
 }