protected void loadItems()

in empire-db-jsf2/src/main/java/org/apache/empire/jsf2/pageelements/BeanListPageElement.java [322:423]
87 lines of code
16 McCabe index (conditional complexity)

    protected void loadItems(boolean initScrollbar)
    {
        // DBReader
        BeanListTableInfo lti = (BeanListTableInfo) getTableInfo();
        DBReader r = new DBReader(getDBContext(rowset));
        try
        { // Check command
            DBCommand queryCmd = lti.getQueryCmd();
            if (queryCmd == null)
                throw new ObjectNotValidException(this);

            boolean loadPageFromPosition = lti.isValid() && lti.isAllowPagination();
            lti.setValid(false);

            if (lti.isSortOrderChanged())
            { // Set Sort order
                setOrderBy(queryCmd);
                lti.setSortOrderChanged(false);
            }
            
            int position = 0;
            int skipRows = 0;
            int maxItems = maxItemCount;
            if (loadPageFromPosition)
            {   // detect position
                position = lti.getPosition();
                if (position > lti.getItemCount() - lti.getPageSize())
                { // position > count of entries is not possible, set to max
                    position = lti.getItemCount() - lti.getPageSize();
                }
                if (position < 0)
                { // position < 0 is not possible, set to 0
                    position = 0;
                }
                // maxItems
                maxItems = lti.getPageSize();
                skipRows = position;
                // constraint
                queryCmd.clearLimit();
                DBMSHandler dbms = r.getContext().getDbms(); 
                if (dbms.isSupported(DBMSFeature.QUERY_LIMIT_ROWS))
                {   // let the database limit the rows
                    if (dbms.isSupported(DBMSFeature.QUERY_SKIP_ROWS))
                    {   // let the database skip the rows
                        queryCmd.skipRows(skipRows);
                        skipRows = 0;
                    }
                    queryCmd.limitRows(skipRows+maxItems);
                }
            }

            // DBReader.open must always be surrounded with a try {} finally {} block!
            r.open(queryCmd);

            // get position from the session
            if (skipRows>0)
            {   // we are not at position 0, "skipping" entries
                r.skipRows(skipRows);
            }

            // Read all Items
            items = r.getBeanList(beanClass, maxItems);
            if (items == null)
                throw new UnexpectedReturnValueException(items, "DBReader.getBeanList");
            generateIdParams(rowset, items);
            assignSelectionMap(items);

            // set position at session object
            if (loadPageFromPosition)
            { // set valid
                if (position + items.size() > lti.getItemCount())
                { // Oops: More items than expected.
                    log.warn("Item count of {} has changed. Adjusting item count.", getPropertyName());
                    lti.init(position + items.size(), lti.getPageSize());
                }
                lti.setPosition(position);
                lti.setModified(false);
                lti.setValid(true);
            }
            else
            { // Init the list
                lti.init(items.size(), 0);
            }
        }
        catch (RuntimeException e)
        {
            log.error("Error loading bean list " + e.getMessage(), e);
            throw e;
        }
        finally
        {
            r.close();
            // Pagination
            if (lti.isAllowPagination())
            { // Scrollbar   
                if (initScrollbar)
                    initScrollbar();
                else
                    updateScrollbar();
            }
        }
    }