package liquibase.lockservice;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentHashMap;
import liquibase.database.Database;
import liquibase.exception.UnexpectedLiquibaseException;
import liquibase.servicelocator.ServiceLocator;
/**
* @author John Sanda
*/
public class LockServiceFactory {
private static LockServiceFactory instance;
private List<LockService> registry = new ArrayList<LockService>();
private Map<Database, LockService> openLockServices = new ConcurrentHashMap<Database, LockService>();
public static synchronized LockServiceFactory getInstance() {
if (instance == null) {
instance = new LockServiceFactory();
}
return instance;
}
/**
* Set the instance used by this singleton. Used primarily for testing.
*/
public static void setInstance(LockServiceFactory lockServiceFactory) {
LockServiceFactory.instance = lockServiceFactory;
}
public static void reset() {
instance = null;
}
private LockServiceFactory() {
Class<? extends LockService>[] classes;
try {
classes = ServiceLocator.getInstance().findClasses(LockService.class);
for (Class<? extends LockService> clazz : classes) {
register(clazz.getConstructor().newInstance());
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
public void register(LockService lockService) {
registry.add(0, lockService);
}
public LockService getLockService(Database database) {
if (!openLockServices.containsKey(database)) {
SortedSet<LockService> foundServices = new TreeSet<LockService>(new Comparator<LockService>() {
@Override
public int compare(LockService o1, LockService o2) {
return -1 * new Integer(o1.getPriority()).compareTo(o2.getPriority());
}
});
for (LockService lockService : registry) {
if (lockService.supports(database)) {
foundServices.add(lockService);
}
}
if (foundServices.size() == 0) {
throw new UnexpectedLiquibaseException("Cannot find LockService for " + database.getShortName());
}
try {
LockService lockService = foundServices.iterator().next().getClass().newInstance();
lockService.setDatabase(database);
openLockServices.put(database, lockService);
} catch (Exception e) {
throw new UnexpectedLiquibaseException(e);
}
}
return openLockServices.get(database);
}
public void resetAll() {
for (LockService lockService : registry) {
lockService.reset();
}
instance = null;
}
}