/*
* Copyright (c) 2009-2010 Clark & Parsia, LLC. <http://www.clarkparsia.com>
*
* 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 com.clarkparsia.empire.spi.guice;
import com.clarkparsia.empire.Empire;
import com.google.inject.MembersInjector;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceProperty;
import javax.persistence.EntityManagerFactory;
import java.lang.reflect.Field;
import java.util.HashMap;
import java.util.Map;
/**
* <p>Implementation of the Guice {@link MembersInjector} interface that injects {@link javax.persistence.EntityManager}
* instances into fields based on the {@link PersistenceContext} annotation.</p>
*
* @author Michael Grove
* @since 0.6
* @version 0.7
*/
public class PersistenceContextInjector<T> implements MembersInjector<T> {
/**
* Field to inject the value to
*/
private Field mField;
/**
* Create a new PersistenceContextInjector
* @param theField the field values will be injected to
*/
PersistenceContextInjector(final Field theField) {
mField = theField;
}
/**
* @inheritDoc
*/
public void injectMembers(final T theT) {
boolean isAccessible = mField.isAccessible();
mField.setAccessible(true);
PersistenceContext aContext = mField.getAnnotation(PersistenceContext.class);
Map<String, String> aMap = new HashMap<String, String>();
for (PersistenceProperty aProp : aContext.properties()) {
aMap.put(aProp.name(), aProp.value());
}
try {
EntityManagerFactory aFactory = Empire.get().persistenceProvider().createEntityManagerFactory(aContext.name(), aMap);
if (aFactory == null) {
throw new RuntimeException("Factory incorrectly initialized, or a factory provided that does not exists was specified. Cannot create EntityManager");
}
mField.set(theT, aFactory.createEntityManager());
}
catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
finally {
mField.setAccessible(isAccessible);
}
}
}