Implement convenient string conversion

Author: tananaev

src/main/java/com/tananaev/jsonpatch/JsonPatch.java

@@ -16,7 +16,9 @@
 
 package com.tananaev.jsonpatch;
 
+import com.google.gson.GsonBuilder;
 import com.google.gson.JsonElement;
+import com.tananaev.jsonpatch.gson.JsonPathSerializer;
 import com.tananaev.jsonpatch.operation.AbsOperation;
 
 import java.util.LinkedList;
@@ -31,4 +33,11 @@ public JsonElement apply(JsonElement original) {
         return result;
     }
 
+    @Override
+    public String toString() {
+        GsonBuilder gsonBuilder = new GsonBuilder();
+        gsonBuilder.registerTypeAdapter(JsonPath.class, new JsonPathSerializer());
+        return gsonBuilder.create().toJson(this);
+    }
+
 }

src/test/java/com/tananaev/jsonpatch/JsonPatchTest.java

@@ -0,0 +1,18 @@
+package com.tananaev.jsonpatch;
+
+import com.google.gson.JsonPrimitive;
+import com.tananaev.jsonpatch.operation.ReplaceOperation;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+public class JsonPatchTest {
+
+    @Test
+    public void toStringTest() throws Exception {
+        JsonPatch patch = new JsonPatch();
+        patch.add(new ReplaceOperation(new JsonPath("/object/key"), new JsonPrimitive("test")));
+        assertEquals("[{\"value\":\"test\",\"op\":\"replace\",\"path\":\"/object/key\"}]", patch.toString());
+    }
+
+}