Examples with ResultIterator org.candlepin.model.ResultIterator used on opensource projects

Example 1 with ResultIterator

use of org.candlepin.model.ResultIterator in project candlepin by candlepin.

the class CandlepinQueryInterceptor method postProcess.

@Override
public void postProcess(ServerResponse response) {
    Object entity = response.getEntity();
    if (entity instanceof CandlepinQuery) {
        final PageRequest pageRequest = ResteasyProviderFactory.getContextData(PageRequest.class);
        final Session session = this.openSession();
        final CandlepinQuery query = (CandlepinQuery) entity;
        final ObjectMapper mapper = this.jsonProvider.locateMapper(Object.class, MediaType.APPLICATION_JSON_TYPE);
        // Use a separate session so we aren't at risk of lazy loading or interceptors closing
        // our cursor mid-stream.
        query.useSession(session);
        // Apply any paging config we may have
        if (pageRequest != null) {
            // Impl note:
            // Sorting will always be required (for consistency) if a page request object is
            // present -- either isPaging() will be true, or we'll have ordering config.
            String sortField = pageRequest.getSortBy() != null ? pageRequest.getSortBy() : AbstractHibernateObject.DEFAULT_SORT_FIELD;
            PageRequest.Order order = pageRequest.getOrder() != null ? pageRequest.getOrder() : PageRequest.DEFAULT_ORDER;
            query.addOrder(order == PageRequest.Order.DESCENDING ? Order.desc(sortField) : Order.asc(sortField));
            if (pageRequest.isPaging()) {
                query.setFirstResult((pageRequest.getPage() - 1) * pageRequest.getPerPage());
                query.setMaxResults(pageRequest.getPerPage());
                // Create a page object for the link header response
                Page page = new Page();
                // This is expensive :(
                page.setMaxRecords(query.getRowCount());
                page.setPageRequest(pageRequest);
                // Note: we don't need to store the page data in the page
                ResteasyProviderFactory.pushContext(Page.class, page);
            }
        }
        // Set the output streamer that will stream our query result
        response.setEntity(new StreamingOutput() {

            @Override
            public void write(OutputStream stream) throws IOException, WebApplicationException {
                JsonGenerator generator = null;
                ResultIterator<Object> iterator = null;
                try {
                    generator = mapper.getJsonFactory().createGenerator(stream);
                    iterator = query.iterate();
                    generator.writeStartArray();
                    while (iterator.hasNext()) {
                        mapper.writeValue(generator, iterator.next());
                    }
                    generator.writeEndArray();
                } finally {
                    if (generator != null) {
                        generator.flush();
                        generator.close();
                    }
                    if (iterator != null) {
                        iterator.close();
                    }
                    if (session != null) {
                        session.close();
                    }
                }
            }
        });
    }
}