// Copyright (c) 2003-2014, Jodd Team (jodd.org). All Rights Reserved.
package jodd.joy.db;
import jodd.db.oom.DbEntityDescriptor;
import jodd.db.oom.DbOomManager;
import jodd.db.oom.DbOomQuery;
import jodd.mutable.MutableLong;
import jodd.petite.meta.PetiteBean;
import jodd.log.Logger;
import jodd.log.LoggerFactory;
import java.util.HashMap;
import java.util.Map;
import static jodd.db.oom.DbOomQuery.query;
/**
* Database in-memory next ID generator.
* It finds the last id (max) for every entity on first use.
* Then it just keeps the count in the memory.
*/
@PetiteBean
public class DbIdGenerator {
private static final Logger log = LoggerFactory.getLogger(DbIdGenerator.class);
protected Map<Class<?>, MutableLong> entityIdsMap = new HashMap<Class<?>, MutableLong>();
/**
* Resets all stored data.
*/
public synchronized void reset() {
entityIdsMap.clear();
}
/**
* Returns next ID for given entity type.
* On the first call, it finds the max value of all IDs and stores it.
* On later calls, stored id is incremented and returned.
*/
public synchronized long nextId(Class entityType) {
MutableLong lastId = entityIdsMap.get(entityType);
if (lastId == null) {
DbOomManager dbOomManager = DbOomManager.getInstance();
DbEntityDescriptor ded = dbOomManager.lookupType(entityType);
String tableName = ded.getTableName();
String idColumn = ded.getIdColumnName();
DbOomQuery dbOomQuery = query("select max(" + idColumn + ") from " + tableName);
long lastLong = dbOomQuery.autoClose().executeCount();
if (log.isDebugEnabled()) {
log.debug("Last id for " + entityType.getName() + " is " + lastLong);
}
lastId = new MutableLong(lastLong);
entityIdsMap.put(entityType, lastId);
}
lastId.value++;
return lastId.value;
}
}