/*
* Copyright 2010 Werner Guttmann
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.castor.jdo.jpa.processors.fieldprocessors;
import java.lang.annotation.Annotation;
import java.lang.reflect.AnnotatedElement;
import javax.persistence.Id;
import javax.persistence.SequenceGenerator;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.castor.core.annotationprocessing.AnnotationTargetException;
import org.castor.core.nature.BaseNature;
import org.castor.jdo.jpa.info.GeneratorNameAlreadyUsedException;
import org.castor.jdo.jpa.info.JPAKeyGeneratorManager;
import org.castor.jdo.jpa.info.JPASequenceGeneratorDescriptor;
import org.castor.jdo.jpa.natures.JPAFieldNature;
import org.castor.jdo.jpa.processors.BaseJPAAnnotationProcessor;
/**
* Processes the JPA annotation {@link SequenceGenerator}. After this processor is done,
* all column specific methods of {@link JPAFieldNature} return valid values.
*
* @author <a href=" mailto:wguttmn AT codehaus DOT org">Werner Guttmann</a>
* @since 1.3.2
*/
public class JPASequenceGeneratorFieldProcessor extends
BaseJPAAnnotationProcessor {
private static final Log LOG = LogFactory
.getLog(JPASequenceGeneratorFieldProcessor.class);
public <I extends BaseNature, A extends Annotation> boolean processAnnotation(
I info, A annotation, AnnotatedElement target)
throws AnnotationTargetException {
if (LOG.isDebugEnabled()) {
LOG.debug("Processing annotation " + annotation.toString());
}
if (!verifyArguments(annotation, target)) {
return false;
}
return processGeneratorDefinition(annotation);
}
/**
* Checks whether all required annotations (as per specification) are present.
*
* @param <A>
* @param annotation The actual annotation.
* @param target The target of the given annotation.
* @return True if all requirements are satisfied.
*/
private <A> boolean verifyArguments(A annotation,
AnnotatedElement target) {
if (!(annotation instanceof SequenceGenerator)
|| (!target.isAnnotationPresent(SequenceGenerator.class))
|| (!target.isAnnotationPresent(Id.class))) {
return false;
}
return true;
}
private <A> boolean processGeneratorDefinition(A annotation) {
SequenceGenerator sequenceGenerator = (SequenceGenerator) annotation;
JPAKeyGeneratorManager manager = JPAKeyGeneratorManager
.getInstance();
JPASequenceGeneratorDescriptor descriptor = JPASequenceGeneratorDescriptor.extract(sequenceGenerator);
try {
manager.add(sequenceGenerator.name(), descriptor);
} catch (GeneratorNameAlreadyUsedException e) {
return false;
}
return true;
}
public Class<? extends Annotation> forAnnotationClass() {
return SequenceGenerator.class;
}
}