I have a question on how Datastore generate cursors, I have this code below and even if the result list is empty a cursor is still returned:
if(asList){
if(startCursor != null && startCursor.getWebSafeString() != null){
fetchOptions.startCursor(Cursor.fromWebSafeString(startCursor.getWebSafeString()));
res = pq.asQueryResultList(fetchOptions);
} else if(startCursor != null && startCursor.getWebSafeString() == null) {
res = pq.asQueryResultList(fetchOptions);
} else {
res = pq.asList(fetchOptions);
}
} else {
if(startCursor != null && startCursor.getWebSafeString() != null){
fetchOptions.startCursor(Cursor.fromWebSafeString(startCursor.getWebSafeString()));
res = pq.asQueryResultIterable(fetchOptions);
} else if(startCursor != null && startCursor.getWebSafeString() == null){
res = pq.asQueryResultIterable(fetchOptions);
} else {
res = pq.asIterator(fetchOptions);
}
}
return res;
res here is a Query result:
String newCursor = res.getCursor().toWebSafeString();
Even if res list is empty a cursor is returned, it is normal? Or something is wrong with this?
You always get a cursor, because the datastore doesn't know or care if there are any more results. What you should do is check that the cursor actually returns something, and if not don't show the link for more results.
Having these "last position" cursors can be really useful for progressive handling of new data.
As in, if you persist the cursor somewhere, you can poll Datastore for new records every so often - and it's cheap because cursors mean Datastore won't scan rows.
Related
Currently we have two endpoints in our API :
One to update one entity
An various ones to update one field of a Collection of entity
The first one only use saveOrUpdate method of hibernate
While the second one create a custom HQL query to update the desired field.
I would like to make only one endpoint. The idea would be receiving a payload representing the entity. Each field of the entity that are not null would be field that we should update.
I wanted to do that in this way, but it doesn't work as setParameter could set parameters that are not in the String.
Any ideas ?
public long update(Collection<Long> toUpdate, SaleItemDTO newValues) {
if (toUpdate.size() == 0) return 0;
StringBuilder hql = new StringBuilder("UPDATE SaleItem SET ");
if (!newValues.getName().isEmpty()) hql.append("name = :name,");
if (newValues.getPrice() != null) hql.append("price = :price,");
if (newValues.getTag() != null) hql.append("tag = :tag,");
if (newValues.getCategory() != null) hql.append("category.id = :categoryId,");
if (newValues.isRecurringSale() != null) hql.append("isRecurringSale = :isRecurringSale,");
if (newValues.isCallProduct() != null) hql.append("callProduct = :callProduct,");
hql.deleteCharAt(hql.length() - 1).append(" WHERE id in :ids");
return this.sessionFactory
.getCurrentSession()
.createQuery(hql.toString())
.setParameter("name", newValues.getName())
.setParameter("price", newValues.getPrice())
.setParameter("tag", newValues.getTag())
.setParameter("categoryId", newValues.getCategory().getId())
.setParameter("isRecurringSale", newValues.isRecurringSale())
.setParameter("callProduct", newValues.isCallProduct())
.setParameter("ids", toUpdate)
.executeUpdate();
}
Okay, fix it with Criteria API
public long update(Collection<Long> toUpdate, SaleItemDTO newValues) {
if (toUpdate.size() == 0) return 0;
CriteriaBuilder criteriaBuilder = this.sessionFactory.getCriteriaBuilder();
// create update
CriteriaUpdate<SaleItem> update = criteriaBuilder.createCriteriaUpdate(SaleItem.class);
// set the root class
Root<SaleItem> saleItemRoot = update.from(SaleItem.class);
// set update and where clause
if (!newValues.getName().isEmpty()) update.set("name", newValues.getName());
if (newValues.getPrice() != null) update.set("price", newValues.getPrice());
//if (newValues.getCategory() != null) update.set("category.id", newValues.getCategory().getId());
if (newValues.getTag() != null) update.set("tag", newValues.getTag());
if (newValues.isRecurringSale() != null) update.set("isRecurringSale", newValues.isRecurringSale());
if (newValues.isCallProduct() != null) update.set("callProduct", newValues.getProduct());
update.where(saleItemRoot.get("id").in(toUpdate));
return this.sessionFactory.getCurrentSession().createQuery(update).executeUpdate();
}
I am using hibernate to get data from oracle.I have Criterion object to make filter for hibernate select like this
Criterion cr6=null;
if(reqrrn != null)
{
cr6=Restrictions.eq("rrn", reqrrn);//o
}
else{
cr6=Restrictions.like("rrn", "",MatchMode.ANYWHERE);
}
Criterion cr20=null;
if(cardPrefix != null && cardPrefix != "")
{
cr20=Restrictions.eq("prefix", cardPrefix);
}
else{
cr20=Restrictions.like("prefix", "",MatchMode.ANYWHERE);
}
criteria.add(Restrictions.and(cr6, cr20));
i have filters like this, but it is usseless when value is null, for example
cardPrefix value is null in database i want to get all values for cardPrefix ,which are filled and null too, how can i do this ?
i solved it. it will be for all parameters like
if(cardPrefix != null && cardPrefix != "")
{
cr20=Restrictions.eq("prefix", cardPrefix);
}
else{
cr20=Restrictions.like("prefix", "",MatchMode.ANYWHERE);
cr1=Restrictions.isNull("prefix");
cr20=Restrictions.or(cr20, cr1);
}
I tried to find a similar question, but I didn't succeed.
In a bean, I'm looping through a ViewEntryCollection several times, adding or deleting entries. Could someone tell me exactly when these objects should be recycled? I want to be able to reuse the whole collection so I don't want to destroy any objects I might still need.
My code:
public static int FTSearchAll(ViewEntryCollection vec, View vw, String cat, String query) throws NotesException {
...
for (ViewEntry ve = nav.getFirst(); ve != null; ) {
ViewEntry next = nav.getNext(ve);
Document doc = ve.getDocument();
if (doc == null)
continue;
try {
Vector v = session.evaluate(query, doc);
if (v != null && v.size() > 0 && (Double) v.elementAt(0) != 0) {
vec.addEntry(ve, false);
} else {
for (ViewEntry dce = vec.getFirstEntry(); dce != null;) {
ViewEntry dcnext = vec.getNextEntry(dce);
if (dce.getNoteID().equals(ve.getNoteID())) {
vec.deleteEntry(dce);
incinerate(dce);
break;
}
dce = dcnext;
}
}
} catch (NotesException ne) {
} finally {
incinerate(ve, doc);
}
ve= next;
}
As always: thanks!
The rule is quite simple: when a Java object pointing to a Notes C object is about to go onto the garbage heap, .recycle() must have been called.
So you need to do that for all entries inside the loop.
My little rule of thumb: the block (think { ... } ) that created a Notes Java object must call its .recycle() function at the end.
Saves you lot of headaches
I see this, but not completely sure whether I miss something or the code keeps its functionality... :S
for (ViewEntry ve = nav.getFirst(); ve != null; ) {
ViewEntry next = nav.getNext(ve);
Document doc = ve.getDocument();
if (doc == null) {
incinerate(ve); // << new
ve = next; // << new
continue;
}
try {
Vector v = session.evaluate(query, doc);
if (v != null && v.size() > 0 && (Double) v.elementAt(0) != 0) {
vec.addEntry(ve, false);
} else {
for (ViewEntry dce = vec.getFirstEntry(); dce != null;) {
ViewEntry dcnext = vec.getNextEntry(dce);
if (dce.getNoteID().equals(ve.getNoteID())) {
vec.deleteEntry(dce);
incinerate(dce, dcnext); // << new
break;
}
incinerate(dce); // << new
dce = dcnext;
}
}
} catch (NotesException ne) {
} finally {
incinerate(ve, doc);
}
ve = next;
}
Maybe it would be better to check another implementation.
Anyway, I recommend you to use the OpenNTF Domino API and get rid of recycle, and you will get also a proper iteration over entries:
http://www.openntf.org/main.nsf/project.xsp?r=project/OpenNTF%20Domino%20API
I am using auto generated JPAController of Netbeans 8 using Java 1.8.
public void create(Physical physical) {
if (physical.getTalentCollection() == null) {
physical.setTalentCollection(new ArrayList<Talent>());
}
EntityManager em = null;
try {
em = getEntityManager();
em.getTransaction().begin();
Specialmark specialmarkId = physical.getSpecialmarkId();
System.out.println(specialmarkId+ "...nullValue");
if (specialmarkId != null) {
System.out.println(specialmarkId+ "...ain't right");
specialmarkId = em.getReference(specialmarkId.getClass(), specialmarkId.getId());
physical.setSpecialmarkId(specialmarkId);
}
.....
}
During physical object creation, Specialmark (part of physical object) is an optional.
It can have a value or be null.
Specialmark in the table physical allows you to have null values.
When Specialmark is null, the if (specialmarkId != null) {...} should skipped. Instead, it got ignored and proceed.
the error message is
"... An instance of a null PK has been incorrectly provided for this find operation.
at db.jpa.PhysicalJpaController.create(PhysicalJpaController.java:57)"
System.out.println(specialmarkId+ "...nullValue");
output "null...nullValue" it shows specialmarkId value is null
System.out.println(specialmarkId+ "...ain't right");
Output "null...ain't right" shows if (specialmarkId != null) {...} has been ignored even specialmarkId is null.
Why does (specialmarkId != null) {...} not work?
I guess specialmarkId is not really null, but specialmarkId.toString() is overwriten for it to return the string "null".
Instead of
System.out.println(specialmarkId+ "...nullValue");
try something like
System.out.println((specialmarkId != null?
specialmarkId.toString() + "(not null)": "(this IS REALLY NULL)")
+ "...nullValue");
So, I'm reading in phone numbers from the built-in contact list and the selected phone number should be put into a text box. This works all fine and dandy for phone numbers that come from google or have been put in manually by the user. However, when it comes to selecting a number that was synced from Facebook to the user's phone, the cursor returns NULL and the text box remains empty.
Here is the code that I'm using to select the number:
if (data != null) {
Uri uri = data.getData();
if (uri != null) {
Cursor c = null;
try {
c = getContentResolver()
.query(uri,
new String[] {
ContactsContract.CommonDataKinds.Phone.NUMBER,
ContactsContract.CommonDataKinds.Phone.TYPE, },
null, null, null);
if (c != null && c.moveToFirst()) {
String number = c.getString(0);
txtPhoneNo.setText(number);
}
} finally {
if (c != null) {
c.close();
}
}
}
}
So, is there anything I can do that will allow me to get the Facebook synced phone numbers, or am I stuck with not being able to use those numbers?