Hi all,
I just added support to the Isis core and applib for Paged datastore
queries.
These extensions don't change any existing behaviour, but do expose
a new query type to the user space: QueryFindAllPaged
A simple usage example:
public List<SimpleClass> someSimpleClasses(final long startIndex, final
long rowCount) {
Query<SimpleClass> query = new
QueryFindAllPaged<SimpleClass>(SimpleClass.class, startIndex, rowCount);
return allMatches(query);
}
Inside PersistenceSession, "QueryFindAllPaged" is mapped onto
"PersistenceQueryFindPaged", which is available to the data stores.
The SQL-OS has a simple implementation that adds "LIMIT
<startIndex>, <rowCount>" to the end of the SQL statement.
This will have to be edited for each database engine: I belive mysql
and postgresql have an incompatible syntax... but I believe it should
be possible to easily define a way to specify the custom string in the
properties file.
There is a simple test in SqlDomainObjectRepository that just checks
that the expected number of instances are returned. It works against
HSQLDB.
May you find this extension useful!
