Fixed ClassNotFoundException when removing classes from the class h…

…ierarchy

RELEASE-NOTES.md

@@ -4,7 +4,7 @@ Release Notes
 
 ### Upcoming Changes
 
-- TBD
+- Fixed `ClassNotFoundException` when removing classes from the class hierarchy
 
 ### JSON Migraine 1.0.0 (2012-11-02)
 

src/main/java/fi/solita/jsonmigraine/internal/DataVersion.java

@@ -1,15 +1,19 @@
-// Copyright © 2012 Solita Oy <www.solita.fi>
+// Copyright © 2012-2013 Solita Oy <www.solita.fi>
 // This software is released under the MIT License.
 // The license text is at http://opensource.org/licenses/MIT
 
 package fi.solita.jsonmigraine.internal;
 
 public class DataVersion {
 
-    public final Class<?> dataType;
+    public final String dataType;
     public final int dataVersion;
 
     public DataVersion(Class<?> dataType, int dataVersion) {
+        this(dataType.getName(), dataVersion);
+    }
+
+    public DataVersion(String dataType, int dataVersion) {
         this.dataType = dataType;
         this.dataVersion = dataVersion;
     }

src/main/java/fi/solita/jsonmigraine/internal/DataVersions.java

@@ -1,4 +1,4 @@
-// Copyright © 2012 Solita Oy <www.solita.fi>
+// Copyright © 2012-2013 Solita Oy <www.solita.fi>
 // This software is released under the MIT License.
 // The license text is at http://opensource.org/licenses/MIT
 
@@ -15,10 +15,10 @@ public class DataVersions {
     public final List<DataVersion> versions = new ArrayList<DataVersion>();
 
     public int getVersion(Class<?> dataType) {
-        return forDataType(dataType).dataVersion;
+        return forDataType(dataType.getName()).dataVersion;
     }
 
-    private DataVersion forDataType(Class<?> dataType) {
+    private DataVersion forDataType(String dataType) {
         for (DataVersion version : versions) {
             if (version.dataType.equals(dataType)) {
                 return version;
@@ -35,7 +35,7 @@ public DataVersions add(DataVersion dataVersion) {
     public JsonNode toJson() {
         ObjectNode json = JsonNodeFactory.instance.objectNode();
         for (DataVersion version : versions) {
-            json.put(version.dataType.getName(), version.dataVersion);
+            json.put(version.dataType, version.dataVersion);
         }
         return json;
     }
@@ -44,19 +44,11 @@ public static DataVersions fromJson(JsonNode json, TypeRenames renames) {
         DataVersions versions = new DataVersions();
         for (String dataType : asIterable(json.getFieldNames())) {
             int dataVersion = json.get(dataType).asInt();
-            versions.add(new DataVersion(toClass(renames.getLatestName(dataType)), dataVersion));
+            versions.add(new DataVersion(renames.getLatestName(dataType), dataVersion));
         }
         return versions;
     }
 
-    private static Class<?> toClass(String fieldName) {
-        try {
-            return Class.forName(fieldName);
-        } catch (ClassNotFoundException e) {
-            throw new RuntimeException(e);
-        }
-    }
-
     private static <T> Iterable<T> asIterable(final Iterator<T> iterator) {
         return new Iterable<T>() {
             @Override

src/test/java/fi/solita/jsonmigraine/RemovingClassesTest.java

@@ -0,0 +1,102 @@
+// Copyright © 2012-2013 Solita Oy <www.solita.fi>
+// This software is released under the MIT License.
+// The license text is at http://opensource.org/licenses/MIT
+
+package fi.solita.jsonmigraine;
+
+import fi.solita.jsonmigraine.api.*;
+import org.codehaus.jackson.JsonNode;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.node.ObjectNode;
+import org.junit.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+public class RemovingClassesTest {
+
+    private final TypeRenames renames = new TypeRenames();
+    private final JsonMigraine jsonMigraine = new JsonMigraine(new ObjectMapper(), renames);
+
+    {
+        renames.rename(ChildV1.class.getName(), ChildV2.class.getName());
+        renames.rename(ParentV1.class.getName(), ParentV1.class.getName().replace("V1", "V2")); // class removed in V2
+    }
+
+    @Test
+    public void can_remove_classes_from_the_class_hierarchy() throws Exception {
+        ChildV1 v1 = new ChildV1();
+        v1.unmodified = "foo";
+        v1.parentField = "bar";
+
+        ChildV2 v2 = upgrade(v1);
+
+        assertThat("should not change unrelated fields", v2.unmodified, is(v1.unmodified));
+        assertThat("should migrate values of relocated fields", v2.relocatedField, is(v1.parentField));
+    }
+
+    private ChildV2 upgrade(ChildV1 v1) throws Exception {
+        String serialized = jsonMigraine.serialize(v1);
+        return (ChildV2) jsonMigraine.deserialize(serialized);
+    }
+
+
+    @Upgradeable(ParentUpgraderV1.class)
+    static class ParentV1 {
+        public String parentField;
+    }
+
+
+    @Upgradeable(ChildUpgraderV1.class)
+    static class ChildV1 extends ParentV1 {
+        public String unmodified;
+    }
+
+    @Upgradeable(ChildUpgraderV2.class)
+    static class ChildV2 {
+        public String relocatedField;
+        public String unmodified;
+    }
+
+    static class ParentUpgraderV1 implements Upgrader {
+
+        @Override
+        public int version() {
+            return 1;
+        }
+
+        @Override
+        public JsonNode upgrade(JsonNode data, int version) {
+            return data;
+        }
+    }
+
+    static class ChildUpgraderV1 implements Upgrader {
+
+        @Override
+        public int version() {
+            return 1;
+        }
+
+        @Override
+        public JsonNode upgrade(JsonNode data, int version) {
+            return data;
+        }
+    }
+
+    static class ChildUpgraderV2 extends ObjectUpgrader {
+
+        @Override
+        public int version() {
+            return 2;
+        }
+
+        @Override
+        public ObjectNode upgrade(ObjectNode data, int version) {
+            if (version == 1) {
+                Refactor.renameField(data, "parentField", "relocatedField");
+            }
+            return data;
+        }
+    }
+}