下面列出了org.hibernate.LockOptions#setAliasSpecificLockMode ( ) 实例代码,或者点击链接到github查看源代码,也可以在右侧发表评论。
@SuppressWarnings({"unchecked", "WeakerAccess"})
protected String buildSelectQuery(Dialect dialect) {
final String alias = "tbl";
final String query = "select " + StringHelper.qualify( alias, valueColumnName ) +
" from " + renderedTableName + ' ' + alias +
" where " + StringHelper.qualify( alias, segmentColumnName ) + "=?";
final LockOptions lockOptions = new LockOptions( LockMode.PESSIMISTIC_WRITE );
lockOptions.setAliasSpecificLockMode( alias, LockMode.PESSIMISTIC_WRITE );
final Map updateTargetColumnsMap = Collections.singletonMap( alias, new String[] { valueColumnName } );
return dialect.applyLocksToSql( query, lockOptions, updateTargetColumnsMap );
}
@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<>()
: 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 );
}