import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Transactional(readOnly = true)
public Slice<ListAnnouncementDTO> list(final ListAnnouncementRequest request, final Pageable pageRequest) {
    final ListAnnouncementFilter filter = new ListAnnouncementFilter(occupationRepository);

    if (!activeUserService.isModeratorOrAdmin()) {
        filter.withSubscriberPerson(activeUserService.requireActivePerson());
    }

    final Optional<Organisation> maybeOrganisation = resolveOrganisation(request);

    switch (request.getDirection()) {
        case SENT:
            maybeOrganisation.ifPresent(filter::withFromOrganisation);
            break;
        case RECEIVED:
            maybeOrganisation.ifPresent(filter::withSubscriberOrganisation);
            break;
        default:
            throw new IllegalArgumentException("Invalid direction");
    }

    return filter.buildPredicate()
            .map(predicate -> announcementRepository.findAllAsSlice(predicate, pageRequest))
            .map(slice -> transform(pageRequest, slice))
            .orElseGet(() -> new SliceImpl<>(emptyList()));
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Override
public <T> Slice<T> findSlice(Query<T> query) {
    List<T> list = findAllInternal(query);
    Pageable pageable = query.getPageable();
    if (pageable != null) {
        boolean hasNext = ((pageable.getPageNumber() + 1) * pageable.getPageSize() < total(query));
        return new SliceImpl<T>(list, query.getPageable(), hasNext);
    } else {
        return new SliceImpl<T>(list);
    }
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Override
@SuppressWarnings("unchecked")
protected Object doExecute(AbstractEbeanQuery query, Object[] values) {

  ParametersParameterAccessor accessor = new ParametersParameterAccessor(parameters, values);
  Pageable pageable = accessor.getPageable();

  Object createQuery = query.createQuery(values);
  List<Object> resultList = null;
  int pageSize = pageable.getPageSize();
  if (createQuery instanceof Query) {
    Query ormQuery = (Query) createQuery;
    ormQuery.setMaxRows(pageSize + 1);

    ormQuery.findList();
  } else if (createQuery instanceof SqlQuery) {
    SqlQuery sqlQuery = (SqlQuery) createQuery;

    sqlQuery.setMaxRows(pageSize + 1);

    sqlQuery.findList();
  } else {
    throw new InvalidEbeanQueryMethodException("query must be Query or SqlQuery");
  }

  boolean hasNext = resultList != null && resultList.size() > pageSize;

  return new SliceImpl<Object>(hasNext ? resultList.subList(0, pageSize) : resultList, pageable, hasNext);
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Override
protected Object doExecute(AbstractMybatisQuery query, Object[] values) {
    MybatisParameters parameters = query.getQueryMethod().getParameters();
    Map<String, Object> parameter = new HashMap<String, Object>();
    int c = 0;
    for (MybatisParameter param : parameters.getBindableParameters()) {
        String name = param.getName();
        if (StringUtils.isEmpty(name)) {
            name = "p" + c;
        }
        parameter.put(name, values[param.getIndex()]);
        c++;
    }


    Pageable pageable = (Pageable) values[parameters.getPageableIndex()];
    if (parameters.hasSortParameter()) {
        parameter.put("_sorts", values[parameters.getSortIndex()]);
    } else {
        parameter.put("_sorts", pageable.getSort());
    }
    parameter.put("offset", pageable.getOffset());
    parameter.put("pageSize", pageable.getPageSize() + 1);
    parameter.put("offsetEnd", pageable.getOffset() + pageable.getPageSize());
    List<Object> resultList = query.getSqlSessionTemplate().selectList(query.getStatementId(), parameter);

    int pageSize = pageable.getPageSize();
    boolean hasNext = resultList.size() > pageSize;

    return new SliceImpl<Object>(hasNext ? resultList.subList(0, pageSize) : resultList, pageable, hasNext);
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
private static <S> Slice<S> toSlice(final List<S> results, final Pageable page) {
    boolean hasNext = false;
    if (results.size() > page.getPageSize()) {
        // Remove the extra element
        results.remove(results.size() - 1);
        hasNext = true;
    }
    return new SliceImpl<>(results, page, hasNext);
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Test
public void findByCanaryUuids() throws Exception {
  List<UUID> canaryUuids = Collections.singletonList(UUID.randomUUID());
  Slice<EncryptedValue> encryptedValues = new SliceImpl(Collections.singletonList(new EncryptedValue()));
  when(encryptedValueRepository.findByEncryptionKeyUuidIn(eq(canaryUuids), any())).thenReturn(encryptedValues);

  assertThat(subject.findByCanaryUuids(canaryUuids), equalTo(encryptedValues));
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Before
public void beforeEach() {
  oldUuid = UUID.randomUUID();
  UUID activeUuid = UUID.randomUUID();

  encryptedValueDataService = mock(EncryptedValueDataService.class);
  keySet = new EncryptionKeySet();
  keySet.add(oldUuid, mock(Key.class));
  keySet.add(activeUuid, mock(Key.class));
  keySet.setActive(activeUuid);

  encryptedValue1 = mock(EncryptedValue.class);
  encryptedValue2 = mock(EncryptedValue.class);
  encryptedValue3 = mock(EncryptedValue.class);

  encryptionKeyCanaryMapper = mock(EncryptionKeyCanaryMapper.class);
  inactiveCanaries = newArrayList(oldUuid);

  when(encryptedValueDataService.findByCanaryUuids(inactiveCanaries))
      .thenReturn(new SliceImpl<>(asList(encryptedValue1, encryptedValue2)))
      .thenReturn(new SliceImpl<>(asList(encryptedValue3)))
      .thenReturn(new SliceImpl<>(new ArrayList<>()));

  final EncryptionKeyRotator encryptionKeyRotator = new EncryptionKeyRotator(encryptedValueDataService,
      encryptionKeyCanaryMapper,
      keySet);

  encryptionKeyRotator.rotate();
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
/**
 * {@inheritDoc}
 * <p>
 * This specific implementation pages by series.
 * </p>
 */
@Override
@Transactional(readOnly = true)
public Slice<Album> findPaginated(int currentPage, Order... orders) {
	// Adjust the page number: Spring Data counts from 0
	currentPage--;

	if (orders.length > 0) {
		throw new UnsupportedOperationException("It is not possible to override the order for pages of albums");
	}
	Pageable pageable = new PageRequest(currentPage,
			configurationService.getConfiguration().getPageSizeForAlbums());

	Slice<MetaSeries> metaSlice = metaSeriesRepo.findAll(pageable);

	// At the very least, there will be that many elements
	List<Album> albumList = new ArrayList<Album>(metaSlice.getNumberOfElements());
	// Add all albums
	for (MetaSeries meta : metaSlice) {
		if (meta.getSeries() != null) {
			LOGGER.debug("Adding all {} albums from {}", meta.getSeries().getAlbums().size(),
					meta.getSeries().getIdentifyingName());
			albumList.addAll(meta.getSeries().getAlbums());
		} else {
			LOGGER.debug("Adding one shot album: {}", meta.getAlbum().getIdentifyingName());
			albumList.add(meta.getAlbum());
		}
	}

	return new SliceImpl<Album>(albumList, pageable, metaSlice.hasNext());
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
/**
 * <P>
 * Slices and pages are similar ways to iterate through the result set in blocks, mimicking a cursor. A
 * {@link org.springframework.data.domain.Slice Slice} is a simpler concept, only requiring to know if further blocks
 * of data are available. A {@link org.springframework.data.domain.Page Page} requires to know how many blocks of data
 * are available in total.
 * </P>
 *
 * @param parameters For the query
 * @param query The query to run
 * @param queryMethod Holds metadata about the query
 * @return Query result
 */
@SuppressWarnings({ "rawtypes", "unchecked" })
private Object executePageSliceQuery(final Object[] parameters, final KeyValueQuery<?> query,
		final QueryMethod queryMethod) {
	long totalElements = -1;

	int indexOfPageRequest = queryMethod.getParameters().getPageableIndex();
	Pageable pageRequest = (Pageable) parameters[indexOfPageRequest];

	/* TODO Eliminate count call for Slice, retrieve "rows+1" instead to determine if next page exists.
	 */
	if (query.getCritieria() == null) {
		totalElements = this.keyValueOperations.count(queryMethod.getEntityInformation().getJavaType());
	} else {
		totalElements = this.keyValueOperations.count(query, queryMethod.getEntityInformation().getJavaType());
	}

	int requiredRows = pageRequest.getPageSize();

	query.setOffset(pageRequest.getOffset());
	query.setRows(pageRequest.getPageSize());

	Iterable<?> resultSet = this.keyValueOperations.find(query, queryMethod.getEntityInformation().getJavaType());
	List<?> content = IterableConverter.toList(resultSet);

	if (queryMethod.isPageQuery()) {
		return new PageImpl(content, pageRequest, totalElements);
	} else {
		boolean hasNext = totalElements > (query.getOffset() + query.getRows());
		if (content.size() > requiredRows) {
			content = content.subList(0, requiredRows);
		}
		return new SliceImpl(content, pageRequest, hasNext);
	}
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
private Slice<T> createSlice(List<T> allResults, Pageable pageable) {

			Iterator<T> iterator = allResults.iterator();
			int processedCount = 0;
			if (pageable.getOffset() > 0) {
				processedCount = scanThroughResults(iterator, pageable.getOffset());
				if (processedCount < pageable.getOffset())
					return new SliceImpl<T>(new ArrayList<T>());
			}
			List<T> results = readPageOfResultsRestrictMaxResultsIfNecessary(iterator, pageable.getPageSize());
			// Scan ahead to retrieve the next page count
			boolean hasMoreResults = scanThroughResults(iterator, 1) > 0;
			if (getResultsRestrictionIfApplicable() != null && getResultsRestrictionIfApplicable().intValue() <= results.size()) hasMoreResults = false; 
			return new SliceImpl<T>(results, pageable, hasMoreResults);
		}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
private Slice<ListAnnouncementDTO> transform(final Pageable pageRequest, final Slice<Announcement> slice) {
    return new SliceImpl<>(announcementDTOTransformer.transform(slice.getContent()), pageRequest, slice.hasNext());
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Override
public Slice<Target> findByFilterOrderByLinkedDistributionSet(final Pageable pageable,
        final Long orderByDistributionId, final FilterParams filterParams) {
    final CriteriaBuilder cb = entityManager.getCriteriaBuilder();
    final CriteriaQuery<JpaTarget> query = cb.createQuery(JpaTarget.class);
    final Root<JpaTarget> targetRoot = query.from(JpaTarget.class);

    // select case expression to retrieve the case value as a column to be
    // able to order based on
    // this column, installed first,...
    final Expression<Object> selectCase = cb.selectCase()
            .when(cb.equal(targetRoot.get(JpaTarget_.installedDistributionSet).get(JpaDistributionSet_.id),
                    orderByDistributionId), 1)
            .when(cb.equal(targetRoot.get(JpaTarget_.assignedDistributionSet).get(JpaDistributionSet_.id),
                    orderByDistributionId), 2)
            .otherwise(100);
    // multiselect statement order by the select case and controllerId
    query.distinct(true);
    // build the specifications and then to predicates necessary by the
    // given filters
    final Predicate[] specificationsForMultiSelect = specificationsToPredicate(buildSpecificationList(filterParams),
            targetRoot, query, cb);

    // if we have some predicates then add it to the where clause of the
    // multiselect
    if (specificationsForMultiSelect.length > 0) {
        query.where(specificationsForMultiSelect);
    }
    // add the order to the multi select first based on the selectCase
    query.orderBy(cb.asc(selectCase), cb.desc(targetRoot.get(JpaTarget_.id)));
    // the result is a Object[] due the fact that the selectCase is an extra
    // column, so it cannot
    // be mapped directly to a Target entity because the selectCase is not a
    // attribute of the
    // Target entity, the the Object array contains the Target on the first
    // index (case of the
    // multiselect order) of the array and
    // the 2nd contains the selectCase int value.
    final int pageSize = pageable.getPageSize();
    final List<JpaTarget> resultList = entityManager.createQuery(query).setFirstResult(pageable.getOffset())
            .setMaxResults(pageSize + 1).getResultList();
    final boolean hasNext = resultList.size() > pageSize;
    return new SliceImpl<>(Collections.unmodifiableList(resultList), pageable, hasNext);
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Override
public Slice<AssignedSoftwareModule> findAllOrderBySetAssignmentAndModuleNameAscModuleVersionAsc(
        final Pageable pageable, final Long orderByDistributionId, final String searchText, final Long typeId) {

    final List<AssignedSoftwareModule> resultList = new ArrayList<>();
    final int pageSize = pageable.getPageSize();
    final CriteriaBuilder cb = entityManager.getCriteriaBuilder();

    // get the assigned software modules
    final CriteriaQuery<JpaSoftwareModule> assignedQuery = cb.createQuery(JpaSoftwareModule.class);
    final Root<JpaSoftwareModule> assignedRoot = assignedQuery.from(JpaSoftwareModule.class);
    assignedQuery.distinct(true);
    final ListJoin<JpaSoftwareModule, JpaDistributionSet> assignedDsJoin = assignedRoot
            .join(JpaSoftwareModule_.assignedTo);
    // build the specifications and then to predicates necessary by the
    // given filters
    final Predicate[] specPredicate = specificationsToPredicate(buildSpecificationList(searchText, typeId),
            assignedRoot, assignedQuery, cb,
            cb.equal(assignedDsJoin.get(JpaDistributionSet_.id), orderByDistributionId));
    // if we have some predicates then add it to the where clause of the
    // multi select
    assignedQuery.where(specPredicate);
    assignedQuery.orderBy(cb.asc(assignedRoot.get(JpaSoftwareModule_.name)),
            cb.asc(assignedRoot.get(JpaSoftwareModule_.version)));
    // don't page the assigned query on database, we need all assigned
    // software modules to filter
    // them out in the unassigned query
    final List<JpaSoftwareModule> assignedSoftwareModules = entityManager.createQuery(assignedQuery)
            .getResultList();
    // map result
    if (pageable.getOffset() < assignedSoftwareModules.size()) {
        assignedSoftwareModules
                .subList(pageable.getOffset(), Math.min(assignedSoftwareModules.size(), pageable.getPageSize()))
                .forEach(sw -> resultList.add(new AssignedSoftwareModule(sw, true)));
    }

    if (assignedSoftwareModules.size() >= pageSize) {
        return new SliceImpl<>(resultList);
    }

    // get the unassigned software modules
    final CriteriaQuery<JpaSoftwareModule> unassignedQuery = cb.createQuery(JpaSoftwareModule.class);
    unassignedQuery.distinct(true);
    final Root<JpaSoftwareModule> unassignedRoot = unassignedQuery.from(JpaSoftwareModule.class);

    Predicate[] unassignedSpec;
    if (!assignedSoftwareModules.isEmpty()) {
        unassignedSpec = specificationsToPredicate(buildSpecificationList(searchText, typeId), unassignedRoot,
                unassignedQuery, cb, cb.not(unassignedRoot.get(JpaSoftwareModule_.id).in(
                        assignedSoftwareModules.stream().map(SoftwareModule::getId).collect(Collectors.toList()))));
    } else {
        unassignedSpec = specificationsToPredicate(buildSpecificationList(searchText, typeId), unassignedRoot,
                unassignedQuery, cb);
    }

    unassignedQuery.where(unassignedSpec);
    unassignedQuery.orderBy(cb.asc(unassignedRoot.get(JpaSoftwareModule_.name)),
            cb.asc(unassignedRoot.get(JpaSoftwareModule_.version)));
    final List<JpaSoftwareModule> unassignedSoftwareModules = entityManager.createQuery(unassignedQuery)
            .setFirstResult(Math.max(0, pageable.getOffset() - assignedSoftwareModules.size()))
            .setMaxResults(pageSize).getResultList();
    // map result
    unassignedSoftwareModules.forEach(sw -> resultList.add(new AssignedSoftwareModule(sw, false)));

    return new SliceImpl<>(resultList);
}
 

import org.springframework.data.domain.SliceImpl; //导入依赖的package包/类
@Transactional(readOnly = true)
@Override
public Slice<Tag> findPaginated(int currentPage, Order... orders) {
	return new SliceImpl<>(repo.findAllWithUsageCounts());
}