Serialized classes update mechanism

Added serialized classes update mechanism and removed the useless initialize method.

src/main/java/org/warp/cowdb/Database.java

@@ -35,7 +35,6 @@ public class Database implements IDatabase {
 	private final DatabaseReferencesIO referencesIO;
 	private final DatabaseReferencesMetadata referencesMetadata;
 	private final DatabaseObjectsIO objectsIO;
-	private final DatabaseDataInitializer dataInitializer;
 	private EnhancedObject loadedRootObject;
 
 	public Database(Path dataFile, Path blocksMetaFile, Path referencesMetaFile) throws IOException {
@@ -54,12 +53,11 @@ public class Database implements IDatabase {
 		this.referencesMetadata = new DatabaseReferencesMetadata(referencesMetaFile);
 		this.referencesIO = new DatabaseReferencesIO(blocksIO, referencesMetadata);
 		this.objectsIO = new DatabaseObjectsIO(this, referencesIO);
-		this.dataInitializer = new DatabaseDataInitializer(objectsIO);
 	}
 
 	@Override
 	public IDataInitializer getDataInitializer() {
-		return dataInitializer;
+		return objectsIO.dataInitializer;
 	}
 
 	@Override
@@ -77,8 +75,8 @@ public class Database implements IDatabase {
 
 	public <T extends EnhancedObject> T loadRoot(Class<T> type) throws IOException {
 		return loadRoot(type, () -> {
-			T obj = objectsIO.instantiateEnhancedObject(type);
-			dataInitializer.initializeDBObject(obj);
+			T obj = objectsIO.toInstance(type);
+			objectsIO.dataInitializer.initializeDBObject(obj);
 			return obj;
 		});
 	}
@@ -118,7 +116,6 @@ public class Database implements IDatabase {
 		public void initializeDBObject(EnhancedObject obj) throws IOException {
 			initializeDBObjectFields(obj);
 			initializeDBObjectProperties(obj);
-			obj.initialize();
 		}
 
 		private void initializeDBObjectFields(EnhancedObject obj) throws IOException {
@@ -197,18 +194,44 @@ public class Database implements IDatabase {
 		}
 	}
 
+	public static class DatabaseEnhancedObjectUpgrader implements EnhancedObjectUpgrader {
+		private final DatabaseObjectsIO objectsIO;
+		private final long[] fieldRefs;
+		private final long[] methodRefs;
+
+		public DatabaseEnhancedObjectUpgrader(DatabaseObjectsIO objectsIO, long[] fieldRefs, long[] methodRefs) {
+			this.objectsIO = objectsIO;
+			this.fieldRefs = fieldRefs;
+			this.methodRefs = methodRefs;
+		}
+
+		@Override
+		@SuppressWarnings("unchecked")
+		public Object getField(int id, DBDataType type, Supplier<Class<?>> enhancedClassType) throws IOException {
+			return objectsIO.loadData(type, fieldRefs[id], enhancedClassType);
+		}
+
+		@Override
+		@SuppressWarnings("unchecked")
+		public Object getMethod(int id, DBDataType type, Supplier<Class<?>> enhancedClassType) throws IOException {
+			return objectsIO.loadData(type, methodRefs[id], enhancedClassType);
+		}
+	}
+
 	public static class DatabaseObjectsIO implements IObjectsIO {
 
 		private final IDatabase database;
 		private final DatabaseReferencesIO referencesIO;
 
 		private final Object accessLock = new Object();
+		private final DatabaseDataInitializer dataInitializer;
 
 		private Kryo kryo = new Kryo();
 
 		private DatabaseObjectsIO(IDatabase database, DatabaseReferencesIO referencesIO) {
 			this.database = database;
 			this.referencesIO = referencesIO;
+			this.dataInitializer = new DatabaseDataInitializer(this);
 			kryo.setRegistrationRequired(false);
 			int id = -90;
 			registerClass(boolean[].class, id++);
@@ -271,6 +294,7 @@ public class Database implements IDatabase {
 				if (buffer.limit() == 0) {
 					return null;
 				}
+				int serializedVersion = Byte.toUnsignedInt(buffer.get());
 				int fieldsCount = buffer.getInt();
 				int methodsCount = buffer.getInt();
 				long[] fieldRefs = new long[fieldsCount];
@@ -281,7 +305,7 @@ public class Database implements IDatabase {
 				for (int i = 0; i < methodsCount; i++) {
 					methodRefs[i] = buffer.getLong();
 				}
-				return preloadEnhancedObject(objectType, fieldRefs, methodRefs);
+				return preloadEnhancedObject(objectType, serializedVersion, fieldRefs, methodRefs);
 			}
 		}
 
@@ -349,8 +373,9 @@ public class Database implements IDatabase {
 			synchronized (accessLock) {
 				if (value != null) {
 					EnhancedObjectFullInfo objectFullInfo = value.getAllInfo();
-					int totalSize = Integer.BYTES * 2 + objectFullInfo.getFieldReferences().length * Long.BYTES + objectFullInfo.getPropertyReferences().length * Long.BYTES;
+					int totalSize = Byte.BYTES + Integer.BYTES * 2 + objectFullInfo.getFieldReferences().length * Long.BYTES + objectFullInfo.getPropertyReferences().length * Long.BYTES;
 					ByteBuffer buffer = ByteBuffer.allocate(totalSize);
+					buffer.put((byte) objectFullInfo.getVersion());
 					buffer.putInt(objectFullInfo.getFieldReferences().length);
 					buffer.putInt(objectFullInfo.getPropertyReferences().length);
 					for (int i = 0; i < objectFullInfo.getFieldReferences().length; i++) {
@@ -359,15 +384,25 @@ public class Database implements IDatabase {
 					for (int i = 0; i < objectFullInfo.getPropertyReferences().length; i++) {
 						buffer.putLong(objectFullInfo.getPropertyReferences()[i]);
 					}
+					long[] fieldReferences = objectFullInfo.getFieldReferences();
+					DBDataType[] fieldTypes = objectFullInfo.getFieldTypes();
+					Field[] fields = objectFullInfo.getFields();
+					long[] propertyReferences = objectFullInfo.getPropertyReferences();
+					DBDataType[] propertyTypes = objectFullInfo.getPropertyTypes();
+					Object[] propertyValues = objectFullInfo.getLoadedPropertyValues();
 					for (int i = 0; i < objectFullInfo.getFieldReferences().length; i++) {
+						if (fields[i] != null) {
 							try {
-							setData(objectFullInfo.getFieldReferences()[i], objectFullInfo.getFieldTypes()[i], objectFullInfo.getFields()[i].get(value));
+								setData(fieldReferences[i], fieldTypes[i], fields[i].get(value));
 							} catch (IllegalAccessException e) {
 								throw new IOException(e);
 							}
 						}
+					}
 					for (int i = 0; i < objectFullInfo.getPropertyReferences().length; i++) {
-						setData(objectFullInfo.getPropertyReferences()[i], objectFullInfo.getPropertyTypes()[i], objectFullInfo.getLoadedPropertyValues()[i]);
+						if (propertyValues[i] != null) {
+							setData(propertyReferences[i], propertyTypes[i], propertyValues[i]);
+						}
 					}
 					buffer.flip();
 					referencesIO.writeToReference(reference, totalSize, buffer);
@@ -713,7 +748,7 @@ public class Database implements IDatabase {
 			return biggestFieldId;
 		}
 
-		private <T extends EnhancedObject> T instantiateEnhancedObject(Class<T> type) throws IOException {
+		private <T extends EnhancedObject> T toInstance(Class<T> type) throws IOException {
 			try {
 				T obj = type.getConstructor().newInstance();
 				obj.database = database;
@@ -725,10 +760,26 @@ public class Database implements IDatabase {
 			}
 		}
 
-		private <T extends EnhancedObject> T preloadEnhancedObject(Class<T> objectType, long[] fieldRefs, long[] methodRefs) throws IOException {
-			T obj = instantiateEnhancedObject(objectType);
+		private <T extends EnhancedObject> T preloadEnhancedObject(Class<T> objectType, int serializedVersion, long[] fieldRefs, long[] methodRefs) throws IOException {
+			// Instantiate the class to an object
+			T obj = toInstance(objectType);
+
+			// Check the serialized version
+			DBClass dbClass = objectType.getAnnotation(DBClass.class);
+			int classVersion = 0;
+			if (dbClass != null) {
+				classVersion = dbClass.version();
+			}
+			if (classVersion > serializedVersion) {
+				DatabaseEnhancedObjectUpgrader enhancedObjectUpgrader = new DatabaseEnhancedObjectUpgrader(this, fieldRefs, methodRefs);
+				dataInitializer.initializeDBObject(obj);
+				obj.onUpgrade(serializedVersion, enhancedObjectUpgrader);
+			} else if (classVersion < serializedVersion) {
+				throw new IllegalStateException("The serialized class is more recent than the current version of that class!");
+			} else {
 				preloadEnhancedObjectFields(obj, fieldRefs);
 				preloadEnhancedObjectProperties(obj, methodRefs);
+			}
 			return obj;
 		}
 

src/main/java/org/warp/cowdb/EnhancedObject.java

@@ -1,17 +1,19 @@
 package org.warp.cowdb;
 
+import org.apache.commons.lang3.NotImplementedException;
 import org.apache.commons.lang3.reflect.MethodUtils;
+import org.warp.jcwdb.ann.DBClass;
 import org.warp.jcwdb.ann.DBDataType;
 import org.warp.jcwdb.ann.DBPropertyGetter;
 import org.warp.jcwdb.ann.DBPropertySetter;
 
-import java.io.IOError;
 import java.io.IOException;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.Map;
 
 public abstract class EnhancedObject {
+	protected final int version;
 	protected IDatabase database;
 	private Field[] fields;
 	private DBDataType[] fieldTypes;
@@ -26,17 +28,15 @@ public abstract class EnhancedObject {
 	private Map<String, DBPropertyGetter> getterMethods;
 
 	public EnhancedObject() {
-
+		version = getClassVersion();
 	}
 
 	public EnhancedObject(IDatabase database) throws IOException {
 		this.database = database;
+		version = getClassVersion();
 		database.getDataInitializer().initializeDBObject(this);
 	}
 
-	public abstract void initialize() throws IOException;
-
-
 	public void setFields(Field[] fields, DBDataType[] fieldTypes, long[] fieldReferences) {
 		this.fields = fields;
 		this.fieldTypes = fieldTypes;
@@ -63,7 +63,7 @@ public abstract class EnhancedObject {
 	}
 
 	public EnhancedObjectFullInfo getAllInfo() {
-		return new EnhancedObjectFullInfo(fieldReferences, fieldTypes, fields, propertyReferences, propertyTypes, loadedPropertyValues);
+		return new EnhancedObjectFullInfo(version, fieldReferences, fieldTypes, fields, propertyReferences, propertyTypes, loadedPropertyValues);
 	}
 
 
@@ -98,4 +98,19 @@ public abstract class EnhancedObject {
 		loadedPropertyValues[propertyId] = value;
 		loadedProperties[propertyId] = true;
 	}
+
+	private int getClassVersion() {
+		DBClass classAnnotation = this.getClass().getAnnotation(DBClass.class);
+		return classAnnotation == null ? 0 : classAnnotation.version();
+	}
+
+	/**
+	 * Called when an unloaded class is older than the actual version
+	 * @param oldObjectVersion
+	 * @param enhancedObjectUpgrader
+	 * @throws IOException
+	 */
+	public void onUpgrade(int oldObjectVersion, EnhancedObjectUpgrader enhancedObjectUpgrader) throws IOException {
+		throw new NotImplementedException("Method onUpgrade() is not implemented for class " + this.getClass().getSimpleName());
+	}
 }

src/main/java/org/warp/cowdb/EnhancedObjectFullInfo.java

@@ -5,6 +5,7 @@ import org.warp.jcwdb.ann.DBDataType;
 import java.lang.reflect.Field;
 
 public class EnhancedObjectFullInfo {
+	private final int version;
 	private final long[] fieldReferences;
 	private final DBDataType[] fieldTypes;
 	private final Field[] fields;
@@ -12,7 +13,11 @@ public class EnhancedObjectFullInfo {
 	private final DBDataType[] propertyTypes;
 	private final Object[] loadedPropertyValues;
 
-	EnhancedObjectFullInfo(long[] fieldReferences, DBDataType[] fieldTypes, Field[] fields, long[] propertyReferences, DBDataType[] propertyTypes, Object[] loadedPropertyValues) {
+	EnhancedObjectFullInfo(int version, long[] fieldReferences, DBDataType[] fieldTypes, Field[] fields, long[] propertyReferences, DBDataType[] propertyTypes, Object[] loadedPropertyValues) {
+		this.version = version;
+		if (version > 255) {
+			throw new IllegalArgumentException();
+		}
 		this.fieldReferences = fieldReferences;
 		this.fieldTypes = fieldTypes;
 		this.fields = fields;
@@ -21,6 +26,10 @@ public class EnhancedObjectFullInfo {
 		this.loadedPropertyValues = loadedPropertyValues;
 	}
 
+	int getVersion() {
+		return version;
+	}
+
 	long[] getFieldReferences() {
 		return fieldReferences;
 	}

src/main/java/org/warp/cowdb/EnhancedObjectUpgrader.java

@@ -0,0 +1,17 @@
+package org.warp.cowdb;
+
+import org.warp.jcwdb.ann.DBDataType;
+
+import java.io.IOException;
+import java.util.function.Supplier;
+
+public interface EnhancedObjectUpgrader {
+	Object getField(int id, DBDataType type, Supplier<Class<?>> enhancedClassType) throws IOException;
+	default Object getField(int id, DBDataType type) throws IOException {
+		return getField(id, type, null);
+	}
+	Object getMethod(int id, DBDataType type, Supplier<Class<?>> enhancedClassType) throws IOException;
+	default Object getMethod(int id, DBDataType type) throws IOException {
+		return getField(id, type, null);
+	}
+}

src/main/java/org/warp/cowdb/lists/EnhancedObjectCowList.java

@@ -25,11 +25,6 @@ public class EnhancedObjectCowList<T extends EnhancedObject> extends CowList<T>
 		super();
 	}
 
-	@Override
-	public void initialize() throws IOException {
-
-	}
-
 	public EnhancedObjectCowList(IDatabase database, Class<T> type) throws IOException {
 		super(database);
 		this.type = type;

src/main/java/org/warp/cowdb/lists/ObjectCowList.java

@@ -27,11 +27,6 @@ public class ObjectCowList<T> extends CowList<T> {
 		indices = new LongArrayList();
 	}
 
-	@Override
-	public void initialize() throws IOException {
-
-	}
-
 	@Override
 	protected T loadItem(long uid) throws IOException {
 		return database.getObjectsIO().loadObject(uid);

src/main/java/org/warp/jcwdb/ann/DBClass.java

@@ -0,0 +1,12 @@
+package org.warp.jcwdb.ann;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ElementType.TYPE})
+public @interface DBClass {
+	int version() default 0;
+}

src/test/java/org/warp/jcwdb/tests/EnhancedClassUpdate.java

@@ -0,0 +1,58 @@
+package org.warp.jcwdb.tests;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.warp.cowdb.Database;
+import org.warp.cowdb.EnhancedObject;
+import org.warp.cowdb.IDatabase;
+import org.warp.jcwdb.ann.DBDataType;
+import org.warp.jcwdb.ann.DBField;
+import org.warp.jcwdb.ann.DBPropertyGetter;
+import org.warp.jcwdb.ann.DBPropertySetter;
+import org.warp.jcwdb.utils.NTestUtils;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import static org.junit.Assert.assertEquals;
+
+public class EnhancedClassUpdate {
+
+	private Path path1;
+	private Path path2;
+	private Path path3;
+	private Database db;
+
+	@Before
+	public void setUp() throws Exception {
+		path1 = Files.createTempFile("db-tests-", ".db");
+		path2 = Files.createTempFile("db-tests-", ".db");
+		path3 = Files.createTempFile("db-tests-", ".db");
+		db = new Database(path1, path2, path3);
+		OldClass root = db.loadRoot(OldClass.class);
+		root.field1 = "Abc";
+		root.field2 = 12;
+		root.field4 = 13;
+		db.close();
+	}
+
+	@Test
+	public void shouldUpdateClass() throws IOException {
+		db = new Database(path1, path2, path3);
+		V2Class root = db.loadRoot(V2Class.class);
+		assertEquals(root.field4, "Abc");
+		assertEquals(root.field2, 12);
+		assertEquals(root.field1, 13L);
+		db.close();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		Files.deleteIfExists(path1);
+		Files.deleteIfExists(path2);
+		Files.deleteIfExists(path3);
+	}
+}

src/test/java/org/warp/jcwdb/tests/MultipleEnhancedObjects.java

@@ -13,7 +13,7 @@ import org.warp.jcwdb.utils.NTestUtils;
 
 import java.io.IOException;
 
-public class NDBMultipleEnhancedObjects {
+public class MultipleEnhancedObjects {
 	private NTestUtils.WrappedDb db;
 	private RootTwoClasses root;
 
@@ -81,10 +81,5 @@ public class NDBMultipleEnhancedObjects {
 		public void setClass4(NTestUtils.RootClass value) {
 			setProperty(value);
 		}
-
-		@Override
-		public void initialize() throws IOException {
-
-		}
 	}
 }

src/test/java/org/warp/jcwdb/tests/OldClass.java

@@ -0,0 +1,19 @@
+package org.warp.jcwdb.tests;
+
+import org.warp.cowdb.EnhancedObject;
+import org.warp.jcwdb.ann.DBClass;
+import org.warp.jcwdb.ann.DBDataType;
+import org.warp.jcwdb.ann.DBField;
+
+import java.io.IOException;
+
+public class OldClass extends EnhancedObject {
+	@DBField(id = 0, type = DBDataType.OBJECT)
+	public String field1;
+
+	@DBField(id = 1, type = DBDataType.INTEGER)
+	public int field2;
+
+	@DBField(id = 3, type = DBDataType.INTEGER)
+	public int field4;
+}

src/test/java/org/warp/jcwdb/tests/V2Class.java

@@ -0,0 +1,33 @@
+package org.warp.jcwdb.tests;
+
+import org.warp.cowdb.EnhancedObject;
+import org.warp.cowdb.EnhancedObjectUpgrader;
+import org.warp.jcwdb.ann.DBClass;
+import org.warp.jcwdb.ann.DBDataType;
+import org.warp.jcwdb.ann.DBField;
+
+import java.io.IOException;
+
+@DBClass(version = 1)
+public class V2Class extends EnhancedObject {
+	@DBField(id = 0, type = DBDataType.LONG)
+	public long field1;
+
+	@DBField(id = 1, type = DBDataType.INTEGER)
+	public int field2;
+
+	@DBField(id = 3, type = DBDataType.OBJECT)
+	public String field4;
+
+	@Override
+	public void onUpgrade(int oldObjectVersion, EnhancedObjectUpgrader enhancedObjectUpgrader) throws IOException {
+		switch (oldObjectVersion) {
+			case 0: {
+				field1 = (long) (Integer) enhancedObjectUpgrader.getField(3, DBDataType.INTEGER);
+				field2 = (int) enhancedObjectUpgrader.getField(1, DBDataType.INTEGER);
+				field4 = (String) enhancedObjectUpgrader.getField(0, DBDataType.OBJECT);
+				break;
+			}
+		}
+	}
+}

src/test/java/org/warp/jcwdb/utils/NSimplestClass.java

@@ -18,10 +18,6 @@ public class NSimplestClass extends EnhancedObject {
 
 	public NSimplestClass(Database database) throws IOException {
 		super(database);
-	}
-
-	@Override
-	public void initialize() throws IOException {
 		field1 = true;
 	}
 }

src/test/java/org/warp/jcwdb/utils/NTestUtils.java

@@ -374,10 +374,5 @@ public class NTestUtils {
 		public boolean test() {
 			return true;
 		}
-
-		@Override
-		public void initialize() throws IOException {
-
-		}
 	}
 }