Java Code Examples for org.hibernate.dialect.Dialect.forUpdateOfColumns()

The following are Jave code examples for showing how to use forUpdateOfColumns() of the org.hibernate.dialect.Dialect class. You can vote up the examples you like. Your votes will be used in our system to get more good examples.
+ Save this method
Example 1
Project: lams   File: QueryLoader.java   View Source Code Vote up 4 votes
@Override
protected String applyLocks(
		String sql,
		QueryParameters parameters,
		Dialect dialect,
		List<AfterLoadAction> afterLoadActions) throws QueryException {
	// can't cache this stuff either (per-invocation)
	// we are given a map of user-alias -> lock mode
	// create a new map of sql-alias -> lock mode

	final LockOptions lockOptions = parameters.getLockOptions();

	if ( lockOptions == null ||
		( lockOptions.getLockMode() == LockMode.NONE && lockOptions.getAliasLockCount() == 0 ) ) {
		return sql;
	}


	// user is request locking, lets see if we can apply locking directly to the SQL...

	// 		some dialects wont allow locking with paging...
	if ( shouldUseFollowOnLocking( parameters, dialect, afterLoadActions ) ) {
		return sql;
	}

	//		there are other conditions we might want to add here, such as checking the result types etc
	//		but those are better served after we have redone the SQL generation to use ASTs.


	// we need both the set of locks and the columns to reference in locks
	// as the ultimate output of this section...
	final LockOptions locks = new LockOptions( lockOptions.getLockMode() );
	final Map<String, String[]> keyColumnNames = dialect.forUpdateOfColumns() ? new HashMap<String, String[]>() : null;

	locks.setScope( lockOptions.getScope() );
	locks.setTimeOut( lockOptions.getTimeOut() );

	for ( Map.Entry<String, String> entry : sqlAliasByEntityAlias.entrySet() ) {
		final String userAlias =  entry.getKey();
		final String drivingSqlAlias = entry.getValue();
		if ( drivingSqlAlias == null ) {
			throw new IllegalArgumentException( "could not locate alias to apply lock mode : " + userAlias );
		}
		// at this point we have (drivingSqlAlias) the SQL alias of the driving table
		// corresponding to the given user alias.  However, the driving table is not
		// (necessarily) the table against which we want to apply locks.  Mainly,
		// the exception case here is joined-subclass hierarchies where we instead
		// want to apply the lock against the root table (for all other strategies,
		// it just happens that driving and root are the same).
		final QueryNode select = (QueryNode) queryTranslator.getSqlAST();
		final Lockable drivingPersister = (Lockable) select.getFromClause()
				.findFromElementByUserOrSqlAlias( userAlias, drivingSqlAlias )
				.getQueryable();
		final String sqlAlias = drivingPersister.getRootTableAlias( drivingSqlAlias );

		final LockMode effectiveLockMode = lockOptions.getEffectiveLockMode( userAlias );
		locks.setAliasSpecificLockMode( sqlAlias, effectiveLockMode );

		if ( keyColumnNames != null ) {
			keyColumnNames.put( sqlAlias, drivingPersister.getRootTableIdentifierColumnNames() );
		}
	}

	// apply the collected locks and columns
	return dialect.applyLocksToSql( sql, locks, keyColumnNames );
}