/**
* 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 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.apache.camel.component.jpa;
import java.lang.reflect.Method;
import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.LockModeType;
import javax.persistence.PersistenceException;
import javax.persistence.Query;
import org.apache.camel.BatchConsumer;
import org.apache.camel.Exchange;
import org.apache.camel.Processor;
import org.apache.camel.ShutdownRunningTask;
import org.apache.camel.impl.ScheduledPollConsumer;
import org.apache.camel.spi.ShutdownAware;
import org.apache.camel.util.CastUtils;
import org.apache.camel.util.ObjectHelper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.orm.jpa.JpaCallback;
/**
* @version
*/
public class JpaConsumer extends ScheduledPollConsumer implements BatchConsumer, ShutdownAware {
private static final transient Logger LOG = LoggerFactory.getLogger(JpaConsumer.class);
private final JpaEndpoint endpoint;
private final TransactionStrategy template;
private QueryFactory queryFactory;
private DeleteHandler<Object> deleteHandler;
private String query;
private String namedQuery;
private String nativeQuery;
private Class resultClass;
private int maxMessagesPerPoll;
private volatile ShutdownRunningTask shutdownRunningTask;
private volatile int pendingExchanges;
private final class DataHolder {
private Exchange exchange;
private Object result;
private EntityManager manager;
private DataHolder() {
}
}
public JpaConsumer(JpaEndpoint endpoint, Processor processor) {
super(endpoint, processor);
this.endpoint = endpoint;
this.template = endpoint.createTransactionStrategy();
}
@Override
protected int poll() throws Exception {
// must reset for each poll
shutdownRunningTask = null;
pendingExchanges = 0;
Object messagePolled = template.execute(new JpaCallback() {
public Object doInJpa(EntityManager entityManager) throws PersistenceException {
Queue<DataHolder> answer = new LinkedList<DataHolder>();
Query query = getQueryFactory().createQuery(entityManager);
configureParameters(query);
List<Object> results = CastUtils.cast(query.getResultList());
for (Object result : results) {
DataHolder holder = new DataHolder();
holder.manager = entityManager;
holder.result = result;
holder.exchange = createExchange(result);
answer.add(holder);
}
int messagePolled;
try {
messagePolled = processBatch(CastUtils.cast(answer));
} catch (Exception e) {
throw new PersistenceException(e);
}
entityManager.flush();
return messagePolled;
}
});
return endpoint.getCamelContext().getTypeConverter().convertTo(int.class, messagePolled);
}
public void setMaxMessagesPerPoll(int maxMessagesPerPoll) {
this.maxMessagesPerPoll = maxMessagesPerPoll;
}
public int processBatch(Queue<Object> exchanges) throws Exception {
int total = exchanges.size();
// limit if needed
if (maxMessagesPerPoll > 0 && total > maxMessagesPerPoll) {
LOG.debug("Limiting to maximum messages to poll " + maxMessagesPerPoll + " as there was " + total + " messages in this poll.");
total = maxMessagesPerPoll;
}
for (int index = 0; index < total && isBatchAllowed(); index++) {
// only loop if we are started (allowed to run)
DataHolder holder = ObjectHelper.cast(DataHolder.class, exchanges.poll());
EntityManager entityManager = holder.manager;
Exchange exchange = holder.exchange;
Object result = holder.result;
// add current index and total as properties
exchange.setProperty(Exchange.BATCH_INDEX, index);
exchange.setProperty(Exchange.BATCH_SIZE, total);
exchange.setProperty(Exchange.BATCH_COMPLETE, index == total - 1);
// update pending number of exchanges
pendingExchanges = total - index - 1;
if (lockEntity(result, entityManager)) {
// process the current exchange
LOG.debug("Processing exchange: {}", exchange);
try {
getProcessor().process(exchange);
} catch (Exception e) {
throw new PersistenceException(e);
}
getDeleteHandler().deleteObject(entityManager, result);
}
}
return total;
}
public boolean deferShutdown(ShutdownRunningTask shutdownRunningTask) {
// store a reference what to do in case when shutting down and we have pending messages
this.shutdownRunningTask = shutdownRunningTask;
// do not defer shutdown
return false;
}
public int getPendingExchangesSize() {
// only return the real pending size in case we are configured to complete all tasks
if (ShutdownRunningTask.CompleteAllTasks == shutdownRunningTask) {
return pendingExchanges;
} else {
return 0;
}
}
public void prepareShutdown() {
// noop
}
public boolean isBatchAllowed() {
// stop if we are not running
boolean answer = isRunAllowed();
if (!answer) {
return false;
}
if (shutdownRunningTask == null) {
// we are not shutting down so continue to run
return true;
}
// we are shutting down so only continue if we are configured to complete all tasks
return ShutdownRunningTask.CompleteAllTasks == shutdownRunningTask;
}
// Properties
// -------------------------------------------------------------------------
@Override
public JpaEndpoint getEndpoint() {
return endpoint;
}
public QueryFactory getQueryFactory() {
if (queryFactory == null) {
queryFactory = createQueryFactory();
if (queryFactory == null) {
throw new IllegalArgumentException("No queryType property configured on this consumer, nor an entityType configured on the endpoint so cannot consume");
}
}
return queryFactory;
}
public void setQueryFactory(QueryFactory queryFactory) {
this.queryFactory = queryFactory;
}
public DeleteHandler<Object> getDeleteHandler() {
if (deleteHandler == null) {
deleteHandler = createDeleteHandler();
}
return deleteHandler;
}
public void setDeleteHandler(DeleteHandler<Object> deleteHandler) {
this.deleteHandler = deleteHandler;
}
public String getNamedQuery() {
return namedQuery;
}
public void setNamedQuery(String namedQuery) {
this.namedQuery = namedQuery;
}
public String getNativeQuery() {
return nativeQuery;
}
public void setNativeQuery(String nativeQuery) {
this.nativeQuery = nativeQuery;
}
public String getQuery() {
return query;
}
public void setQuery(String query) {
this.query = query;
}
public Class getResultClass() {
return resultClass;
}
public void setResultClass(Class resultClass) {
this.resultClass = resultClass;
}
// Implementation methods
// -------------------------------------------------------------------------
/**
* A strategy method to lock an object with an exclusive lock so that it can
* be processed
*
* @param entity the entity to be locked
* @param entityManager entity manager
* @return true if the entity was locked
*/
protected boolean lockEntity(Object entity, EntityManager entityManager) {
if (!getEndpoint().isConsumeDelete() || !getEndpoint().isConsumeLockEntity()) {
return true;
}
try {
LOG.debug("Acquiring exclusive lock on entity: {}", entity);
entityManager.lock(entity, LockModeType.WRITE);
return true;
} catch (Exception e) {
if (LOG.isDebugEnabled()) {
LOG.debug("Failed to achieve lock on entity: " + entity + ". Reason: " + e, e);
}
return false;
}
}
protected QueryFactory createQueryFactory() {
if (query != null) {
return QueryBuilder.query(query);
} else if (namedQuery != null) {
return QueryBuilder.namedQuery(namedQuery);
} else if (nativeQuery != null) {
if (resultClass != null) {
return QueryBuilder.nativeQuery(nativeQuery, resultClass);
} else {
return QueryBuilder.nativeQuery(nativeQuery);
}
} else {
Class<?> entityType = endpoint.getEntityType();
if (entityType == null) {
return null;
} else {
// Check if we have a property name on the @Entity annotation
String name = getEntityName(entityType);
if (name != null) {
return QueryBuilder.query("select x from " + name + " x");
} else {
// Remove package name of the entity to be conform with JPA 1.0 spec
return QueryBuilder.query("select x from " + entityType.getSimpleName() + " x");
}
}
}
}
protected String getEntityName(Class<?> clazz) {
Entity entity = clazz.getAnnotation(Entity.class);
// Check if the property name has been defined for Entity annotation
if (entity != null && !entity.name().equals("")) {
return entity.name();
} else {
return null;
}
}
protected DeleteHandler<Object> createDeleteHandler() {
// look for @Consumed to allow custom callback when the Entity has been consumed
Class<?> entityType = getEndpoint().getEntityType();
if (entityType != null) {
List<Method> methods = ObjectHelper.findMethodsWithAnnotation(entityType, Consumed.class);
if (methods.size() > 1) {
throw new IllegalArgumentException("Only one method can be annotated with the @Consumed annotation but found: " + methods);
} else if (methods.size() == 1) {
final Method method = methods.get(0);
return new DeleteHandler<Object>() {
public void deleteObject(EntityManager entityManager, Object entityBean) {
ObjectHelper.invokeMethod(method, entityBean);
}
};
}
}
if (getEndpoint().isConsumeDelete()) {
return new DeleteHandler<Object>() {
public void deleteObject(EntityManager entityManager, Object entityBean) {
entityManager.remove(entityBean);
}
};
} else {
return new DeleteHandler<Object>() {
public void deleteObject(EntityManager entityManager, Object entityBean) {
// do nothing
}
};
}
}
protected void configureParameters(Query query) {
int maxResults = endpoint.getMaximumResults();
if (maxResults > 0) {
query.setMaxResults(maxResults);
}
}
protected Exchange createExchange(Object result) {
Exchange exchange = endpoint.createExchange();
exchange.getIn().setBody(result);
exchange.getIn().setHeader(JpaConstants.JPA_TEMPLATE, endpoint.getTemplate());
return exchange;
}
}