/**
* see <a
* href="http://www.ibm.com/developerworks/forums/dw_thread.jsp?thread=175971&forum=778&cat=9&ca=drs-fo">
* Best practice for EntityManager queries on a partitioned grid</a>
*
* @param queryString
* @param paramNames
* @param values
* @return list of the matching entities found on the partitions of the grid
*/
@SuppressWarnings("unchecked")
public List<Entity> findByNamedParam(
final String queryString, final String[] paramNames, final Object[] values) {
Validate.notNull(paramNames, "paramNames");
Validate.notNull(values, "values");
Validate.isTrue(
paramNames.length == values.length,
"Length of paramNames array must match length of values array");
if (logger.isDebugEnabled()) {
logger.debug(
"> distributedFind(query="
+ queryString
+ ", paramNames="
+ Arrays.asList(paramNames)
+ ", values='"
+ Arrays.asList(values)
+ ")");
}
try {
AgentManager agentManager =
ObjectGridUtils.getCurrentSession(this.objectGrid)
.getMap(QueryAgent.AGENT_RUNNER_MAP_NAME)
.getAgentManager();
MapGridAgent agent = new QueryAgent<Entity>(queryString, paramNames, values);
Map<Integer, List<Entity>> employeesByPartitionId = agentManager.callMapAgent(agent);
List<Entity> result = new ArrayList<Entity>();
for (Entry<Integer, List<Entity>> entry : employeesByPartitionId.entrySet()) {
Integer partitionId = entry.getKey();
List<Entity> partitionResults = entry.getValue();
if (logger.isDebugEnabled()) {
logger.debug("Found " + partitionResults.size() + " entries on partition " + partitionId);
}
result.addAll(partitionResults);
}
return result;
} catch (RuntimeException e) {
throw new RuntimeException(
"Exception querying '"
+ queryString
+ "' with paramNames="
+ Arrays.asList(paramNames)
+ ", values="
+ Arrays.asList(values)
+ " via the QueryAgent",
e);
} catch (UndefinedMapException e) {
throw new RuntimeException(
"Map '"
+ QueryAgent.AGENT_RUNNER_MAP_NAME
+ "' used by QueryAgent to route queries was not found",
e);
}
}
/**
* Obtains a {@link ThreadLocal} based {@link Session}. If none exist, creates one.
*
* @return the current Session
* @see org.hibernate.SessionFactory#getCurrentSession()
*/
public Session getCurrentSession() {
return ObjectGridUtils.getCurrentSession(objectGrid);
}
/**
* Obtains a {@link ThreadLocal} based {@link EntityManager}. If none exist, creates one.
*
* @return the current EntityManager
* @see org.hibernate.SessionFactory#getCurrentSession()
*/
public EntityManager getCurrentEntityManager() {
return ObjectGridUtils.getCurrentSession(this.objectGrid).getEntityManager();
}
