@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String source = req.getParameter("source");
ImagesService imagesService = ImagesServiceFactory.getImagesService();
DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
List<Filter> filters = new ArrayList<Filter>();
Query query = new Query(GAEFeedRepository.FEED_ITEM_KIND);
filters.add(new Query.FilterPredicate("source", FilterOperator.EQUAL, source));
filters.add(new Query.FilterPredicate("img1A", FilterOperator.EQUAL, 1));
filters.add(new Query.FilterPredicate("img2A", FilterOperator.EQUAL, 1));
query.setFilter(CompositeFilterOperator.and(filters));
query.addSort("publishedDate", SortDirection.DESCENDING);
PreparedQuery pq = datastore.prepare(query);
int pageSize = 30;
resp.setContentType("text/html");
resp.getWriter().println(" <ul>");
FetchOptions fetchOptions = FetchOptions.Builder.withLimit(pageSize);
String startCursor = req.getParameter("cursor");
// If this servlet is passed a cursor parameter, let's use it
if (startCursor != null) {
fetchOptions.startCursor(Cursor.fromWebSafeString(startCursor));
}
QueryResultList<Entity> results = pq.asQueryResultList(fetchOptions);
for (Entity entity : results) {
resp.getWriter()
.println(
"<li>"
+ entity.getProperty("imageLink")
+ " / "
+ imagesService.getServingUrl(
ServingUrlOptions.Builder.withBlobKey((BlobKey) entity.getProperty("img2")))
+ " / <img height=40 width=40 src=\""
+ imagesService.getServingUrl(
ServingUrlOptions.Builder.withBlobKey((BlobKey) entity.getProperty("img2")))
+ "\" />");
}
resp.getWriter().println("</li> </entity></ul> ");
String cursor = results.getCursor().toWebSafeString();
// Assuming this servlet lives at '/people'
resp.getWriter()
.println(
"<a href=\"/p8admin/ListFeedItems?cursor="
+ cursor
+ "&source="
+ source
+ "\">Next page</a>");
}
/**
* This method lists all the entities inserted in datastore. It uses HTTP GET method and paging
* support.
*
* @return A CollectionResponse class containing the list of all entities persisted and a cursor
* to the next page.
* @throws UnauthorizedException
*/
@ApiMethod(
name = "findAll",
scopes = {Config.EMAIL_SCOPE},
clientIds = {Config.CHROME_CLIENT_ID, Config.WEB_CLIENT_ID, Config.API_EXPLORER_CLIENT_ID})
public CollectionResponse<ServiceResponse> findAll(
@Named("_name") String _name,
@Nullable @Named("cursor") String cursorString,
@Nullable @Named("limit") Integer limit,
User user)
throws UnauthorizedException {
if (user == null) {
throw new UnauthorizedException("UnauthorizedException # User is Null.");
}
DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
if (limit == null) {
limit = 10;
}
FetchOptions fetchOptions = FetchOptions.Builder.withLimit(limit);
if (cursorString != null) {
fetchOptions.startCursor(Cursor.fromWebSafeString(cursorString));
}
Query q = new Query(_name);
q.addSort("_updatedAt", SortDirection.DESCENDING);
PreparedQuery pq = datastore.prepare(q);
QueryResultList<Entity> results = pq.asQueryResultList(fetchOptions);
List<ServiceResponse> responses = new ArrayList<ServiceResponse>();
ServiceResponse res = null;
for (Entity entity : results) {
res = new ServiceResponse();
// TODO add properties from entity to service response
res.set_id(entity.getKey().getId());
res.set_createdAt((Date) entity.getProperty(_createdAt));
res.set_createdBy((String) entity.getProperty(_createdBy));
res.set_upatedAt((Date) entity.getProperty(_updatedAt));
res.set_updatedBy((String) entity.getProperty(_updatedBy));
res.set_status((String) entity.getProperty(_status));
Text dataText = (Text) entity.getProperty(data);
res.setData(dataText.getValue());
responses.add(res);
}
cursorString = results.getCursor().toWebSafeString();
return CollectionResponse.<ServiceResponse>builder()
.setItems(responses)
.setNextPageToken(cursorString)
.build();
}
/* (non-Javadoc)
* @see com.googlecode.objectify.Query#getKey()
*/
@Override
public Key<T> getKey() {
FetchOptions opts = FetchOptions.Builder.withLimit(1);
if (this.offset > 0) opts = opts.offset(this.offset);
Iterator<Entity> it = this.prepareKeysOnly().asIterator(opts);
if (it.hasNext()) {
Entity ent = it.next();
return this.factory.rawKeyToTypedKey(ent.getKey());
} else {
return null;
}
}
/**
* @return a set of fetch options for the current limit and offset, or null if there is no limit
* or offset.
*/
private FetchOptions fetchOptions() {
// The FetchOptions builder interface is really, really awful
if (this.cursor != null) {
FetchOptions opts = FetchOptions.Builder.withCursor(this.cursor);
if (this.limit != 0) opts = opts.limit(this.limit);
if (this.offset != 0) opts = opts.offset(this.offset);
return opts;
} else if (this.limit != 0) {
FetchOptions opts = FetchOptions.Builder.withLimit(this.limit);
if (this.offset != 0) opts = opts.offset(this.offset);
return opts;
} else if (this.offset != 0) {
FetchOptions opts = FetchOptions.Builder.withOffset(this.offset);
return opts;
} else {
return null;
}
}
/* (non-Javadoc)
* @see com.googlecode.objectify.Query#get()
*/
@Override
public T get() {
// The underlying datastore is basically doing this for PreparedQuery.asSingleEntity(),
// so let's do it ourselves and integrate offset()
FetchOptions opts = FetchOptions.Builder.withLimit(1);
if (this.offset > 0) opts = opts.offset(this.offset);
if (this.cursor != null) opts = opts.cursor(this.cursor);
Iterator<Entity> it = this.prepare().asIterator(opts);
if (it.hasNext()) {
Entity ent = it.next();
EntityMetadata<T> metadata = this.factory.getMetadata(ent.getKey());
return metadata.toObject(ent);
} else {
return null;
}
}
/**
* @return a set of fetch options for the current limit, offset, and cursors, based on the default
* fetch options. There will always be options even if default.
*/
private FetchOptions fetchOptions() {
FetchOptions opts = FetchOptions.Builder.withDefaults();
if (this.startAt != null) opts = opts.startCursor(this.startAt);
if (this.endAt != null) opts = opts.endCursor(this.endAt);
if (this.limit != 0) opts = opts.limit(this.limit);
if (this.offset != 0) opts = opts.offset(this.offset);
if (this.chunk == null) opts = opts.chunkSize(DEFAULT_CHUNK_SIZE);
else opts = opts.chunkSize(this.chunk);
return opts;
}
/**
* Tests pagination of datastore entities. Verifies forward and backward paging returns entities
* in the exact same order, even with duplicate values.
*
* @throws Exception
*/
public void test() throws Exception {
// Initialize some test entities.
final List<Entity> entities = initializeTestData();
// Add the entities to the datastore.
DatastoreServiceFactory.getDatastoreService().put(entities);
// Create a query to get the people, sorted by their initials.
Query q = new Query(KIND);
q.addSort(PROPERTY_NAME, SortDirection.ASCENDING);
// This is to guarantee the order of duplicate initials. This is not
// necessary if you are not concerned with the order of the duplicates.
q.addSort(KEY, SortDirection.ASCENDING);
// Fetch with a page size of 30 people.
final FetchOptions options = FetchOptions.Builder.withDefaults();
options.limit(30);
// Get first page.
final Page page1 = getPage(q, options);
System.out.println("Page 1");
System.out.println(page1);
// Get the next page by setting the cursor to the "next" cursor
// from the current page.
options.startCursor(page1.next);
final Page page2 = getPage(q, options);
System.out.println("Page 2");
System.out.println(page2);
// Make sure the next page starts after the previous page.
assertTrue(page1.last().compareTo(page2.first()) < 0);
// Get the next page by setting the cursor to the "next" cursor
// from the current page.
options.startCursor(page2.next);
final Page page3 = getPage(q, options);
System.out.println("Page 3");
System.out.println(page3);
// Make sure the next page starts after the previous page.
assertTrue(page1.last().compareTo(page2.first()) < 0);
// For paging backward, create the same query in the reverse order.
// Of course, each page will create a new query according to the
// page direction desired.
q = new Query(KIND);
q.addSort(PROPERTY_NAME, SortDirection.DESCENDING);
q.addSort(KEY, SortDirection.DESCENDING);
// Get the previous page by setting the cursor to the "previous"
// cursor from the current page.
options.startCursor(page3.previous);
final Page page2a = getPage(q, options);
System.out.println("Page 2a");
// As the page will be returned in the reverse order because the
// query is reversed, reverse the page for comparison with the
// original.
final Page reverse2a = page2a.reverse();
System.out.println(reverse2a);
// Make sure this page 2 is exactly like the original.
assertEquals(page2, reverse2a);
// Get the previous page by setting the cursor to the "previous"
// cursor from the current page.
options.startCursor(page2a.next);
final Page page1a = getPage(q, options);
System.out.println("Page 1a");
// As the page will be returned in the reverse order because the
// query is reversed, reverse the page for comparison with the
// original.
final Page reverse1a = page1a.reverse();
System.out.println(reverse1a);
// Make sure this page 1 is exactly like the original.
assertEquals(page1, reverse1a);
}