DataSourcePool poolToSearch = pool;
if (pool==null) poolToSearch=DataSourcePool.global;
// Do not add the result in the datapool yet, but rather add this object on success
DataSource ds = poolToSearch.provide(id,dscId,realOption,false);
if (ds==null) return null;
if (ds instanceof EmptyDataSource){
DefaultEmptyDataSource emptyDs = new DefaultEmptyDataSource(id, marker + dscId, optionalInformation);
EmptyDataSourcePool.global.addEmptyDaSource(id, emptyDs);