| /******************************************************************************* |
| * Copyright (c) 2009, 2010 Oracle. All rights reserved. |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v1.0, which accompanies this distribution |
| * and is available at http://www.eclipse.org/legal/epl-v10.html. |
| * |
| * Contributors: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.jpa.core.jpa2; |
| |
| import java.io.Serializable; |
| |
| /** |
| * JPA 2.0 Canonical Metamodel synchronizer. |
| * <p> |
| * Notes: |
| * <ul><li> |
| * When a JPA project is first created (e.g. when the user adds the JPA |
| * Facet to a Faceted project or when a workspace containing a JPA project is |
| * opened), if it is configured to generate the |
| * Canonical Metamodel (i.e. its metamodel source folder is non-null), it will |
| * first discover what metamodel classes are already present in the metamodel |
| * source folder. Any class appropriately annotated with |
| * <code>javax.persistence.metamodel.StaticMetamodel</code> |
| * and <code>javax.annotation.Generated</code> |
| * will be added to the Canonical Metamodel |
| * (see {@link org.eclipse.jpt.jpa.core.internal.resource.java.source.SourcePersistentType#isGeneratedMetamodel()}). |
| * Once the JPA project's context model is constructed, a new Canonical |
| * Metamodel is generated and merged with the classes already present in the |
| * metamodel source folder. |
| * </li><li> |
| * When a JPA project's metamodel source folder setting is cleared, the Canonical |
| * Metamodel is cleared from the context model, but the generated source files are |
| * left in place. |
| * </li><li> |
| * When a JPA project's metamodel source folder is set to a non-null value, |
| * like when a JPA project is first created, the resulting Canonical Metamodel |
| * will be merged with whatever is already present in the folder. |
| * </li></ul> |
| * <p> |
| * Provisional API: This interface is part of an interim API that is still |
| * under development and expected to change significantly before reaching |
| * stability. It is available at this early stage to solicit feedback from |
| * pioneering adopters on the understanding that any code that uses this API |
| * will almost certainly be broken (repeatedly) as the API evolves. |
| * |
| * @version 2.3 |
| * @since 2.3 |
| */ |
| public interface MetamodelSynchronizer { |
| |
| void initializeMetamodel(); |
| |
| void synchronizeMetamodel(); |
| |
| void disposeMetamodel(); |
| |
| |
| /** |
| * Singleton implemetation of the metamodel synchronizer interface that |
| * does nothing. (Not sure we need this....) |
| */ |
| final class Null implements MetamodelSynchronizer, Serializable { |
| public static final MetamodelSynchronizer INSTANCE = new Null(); |
| public static MetamodelSynchronizer instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Null() { |
| super(); |
| } |
| public void initializeMetamodel() { |
| // do nothing |
| } |
| public void synchronizeMetamodel() { |
| // do nothing |
| } |
| public void disposeMetamodel() { |
| // do nothing |
| } |
| @Override |
| public String toString() { |
| return "MetamodelSynchronizer.Null"; //$NON-NLS-1$ |
| } |
| private static final long serialVersionUID = 1L; |
| private Object readResolve() { |
| // replace this object with the singleton |
| return INSTANCE; |
| } |
| } |
| |
| } |