tx-control-providers/jpa/tx-control-provider-jpa-common/src/main/java/org/apache/aries/tx/control/jpa/common/impl/AbstractJPAEntityManagerProvider.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 WARRANTIESOR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.aries.tx.control.jpa.common.impl;

import java.util.concurrent.atomic.AtomicBoolean;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;

import org.osgi.service.transaction.control.TransactionControl;
import org.osgi.service.transaction.control.TransactionException;
import org.osgi.service.transaction.control.jpa.JPAEntityManagerProvider;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public abstract class AbstractJPAEntityManagerProvider implements JPAEntityManagerProvider, AutoCloseable {

	private static final Logger LOG = LoggerFactory.getLogger(AbstractJPAEntityManagerProvider.class);
	
	private final EntityManagerFactory emf;

	private final Runnable onClose;
	
	private final AtomicBoolean closed = new AtomicBoolean(false);
	
	public AbstractJPAEntityManagerProvider(EntityManagerFactory emf, Runnable onClose) {
		this.emf = emf;
		this.onClose = onClose;
	}

	@Override
	public abstract EntityManager getResource(TransactionControl txControl)
			throws TransactionException;

	
	public EntityManager createEntityManager() {
		if(closed.get()) throw new IllegalStateException("This resource provider is no longer in use");
		return emf.createEntityManager();
	}

	public void close() {
		closed.set(true);
		if(onClose != null) {
			try {
				onClose.run();
			} catch (Exception e) {
				LOG.warn("An error occurred shutting down the JPAEntityManagerProvider {}", emf, e);
			}
		}
	}
}