We have to implement a logic to write the unique code generation in Java. The concept is when we generate the code the system will check if the code is already generate or not. If already generate the system create new code and check again. But this logic fails in some case and we cannot able to identify what is the issue is
Here is the code to create the unique code
Integer code = null;
try {
int max = 999999;
int min = 100000;
code = (int) Math.round(Math.random() * (max - min + 1) + min);
PreOrders preObj = null;
preObj = WebServiceDao.getInstance().preOrderObj(code.toString());
if (preObj != null) {
createCode();
}
} catch (Exception e) {
exceptionCaught();
e.printStackTrace();
log.error("Exception in method createCode() - " + e.toString());
}
return code;
}
The function preOrderObj is calling a function to check the code exists in the database if exists return the object. We are using Hibernate to map the database functions and Mysql on the backend.
Here is the function preOrderObj
PreOrders preOrderObj = null;
List<PreOrders> preOrderList = null;
SessionFactory sessionFactory =
(SessionFactory) ServletActionContext.getServletContext().getAttribute(HibernateListener.KEY_NAME);
Session Hibernatesession = sessionFactory.openSession();
try {
Hibernatesession.beginTransaction();
preOrderList = Hibernatesession.createCriteria(PreOrders.class).add(Restrictions.eq("code", code)).list(); // removed .add(Restrictions.eq("status", true))
if (!preOrderList.isEmpty()) {
preOrderObj = (PreOrders) preOrderList.iterator().next();
}
Hibernatesession.getTransaction().commit();
Hibernatesession.flush();
} catch (Exception e) {
Hibernatesession.getTransaction().rollback();
log.debug("This is my debug message.");
log.info("This is my info message.");
log.warn("This is my warn message.");
log.error("This is my error message.");
log.fatal("Fatal error " + e.getStackTrace().toString());
} finally {
Hibernatesession.close();
}
return preOrderObj;
}
Please guide us to identify the issue.
In createCode method, when the random code generated already exist in database, you try to call createCode again. However, the return value from the recursive call is not updated to the code variable, hence the colliding code is still returned and cause error.
To fix the problem, update the method as
...
if (preObj != null) {
//createCode();
code = createCode();
}
...
Such that the code is updated.
By the way, using random number to generate unique value and test uniqueness through query is a bit strange. You may try Auto Increment if you want unique value.
Related
I'm trying to develop a small Application for a Zebra handheld rfid reader and can't find a way to access the MemoryBank of the tag. My reader configuration is as follows:
private void ConfigureReader() {
if (reader.isConnected()) {
TriggerInfo triggerInfo = new TriggerInfo();
triggerInfo.StartTrigger.setTriggerType(START_TRIGGER_TYPE.START_TRIGGER_TYPE_IMMEDIATE);
triggerInfo.StopTrigger.setTriggerType(STOP_TRIGGER_TYPE.STOP_TRIGGER_TYPE_IMMEDIATE);
try {
// receive events from reader
if (eventHandler == null){
eventHandler = new EventHandler();
}
reader.Events.addEventsListener(eventHandler);
// HH event
reader.Events.setHandheldEvent(true);
// tag event with tag data
reader.Events.setTagReadEvent(true);
reader.Events.setAttachTagDataWithReadEvent(true);
// set trigger mode as rfid so scanner beam will not come
reader.Config.setTriggerMode(ENUM_TRIGGER_MODE.RFID_MODE, true);
// set start and stop triggers
reader.Config.setStartTrigger(triggerInfo.StartTrigger);
reader.Config.setStopTrigger(triggerInfo.StopTrigger);
} catch (InvalidUsageException e) {
e.printStackTrace();
} catch (OperationFailureException e) {
e.printStackTrace();
}
}
}
And the eventReadNotify looks like this:
public void eventReadNotify(RfidReadEvents e) {
// Recommended to use new method getReadTagsEx for better performance in case of large tag population
TagData[] myTags = reader.Actions.getReadTags(100);
if (myTags != null) {
for (int index = 0; index < myTags.length; index++) {
Log.d(TAG, "Tag ID " + myTags[index].getTagID());
ACCESS_OPERATION_CODE aoc = myTags[index].getOpCode();
ACCESS_OPERATION_STATUS aos = myTags[index].getOpStatus();
if (aoc == ACCESS_OPERATION_CODE.ACCESS_OPERATION_READ && aos == ACCESS_OPERATION_STATUS.ACCESS_SUCCESS) {
if (myTags[index].getMemoryBankData().length() > 0) {
Log.d(TAG, " Mem Bank Data " + myTags[index].getMemoryBankData());
}
}
}
}
}
When I'm scanning a tag I get the correct TagID but both myTags[index].getOpCode() and myTags[index].getOpStatus() return null values.
I appreciate every suggestion that might lead to a successful scan.
Thanks.
I managed to find a solution for my problem. To perform any Read or Write task with Zebra Handheld Scanners the following two conditions must be satisfied. Look here for reference: How to write to RFID tag using RFIDLibrary by Zebra?
// make sure Inventory is stopped
reader.Actions.Inventory.stop();
// make sure DPO is disabled
reader.Config.setDPOState(DYNAMIC_POWER_OPTIMIZATION.DISABLE);
You have to stop the inventory and make sure to disable dpo in order to get data other than the TagID from a Tag. Unfortunately this isn't mentioned in the docu for Reading RFID Tags.
I want to delete documents for which a specific property has been set in the current version. If this property has been set all versions of that document need to be removed.
My current implementation which searches for IsCurrentVersion = TRUE and foo = 'bar' has the problem that only the current version gets removed and not the older ones. So I assume that I need to delete the complete VersionSeries ?
Till now I use
doc.delete();
doc.save(RefreshMode.NO_REFRESH);
for each document I find. How can I retrieve all documents from the series and have them deleted too ? And is it more efficient if I add this to a batch ?
You should call the
delete()
method for the VersionSeries (http://www-304.ibm.com/support/knowledgecenter/SSNW2F_5.2.0/com.ibm.p8.ce.dev.java.doc/com/filenet/api/core/VersionSeries.html) instance,
VersionSeries vs = doc.getVersionSeries();
vs.delete();
vs.save(Refresh.NO_REFRESH);
Quote from docs
Caution: The delete and moveContent methods impact all document versions in the version series. That is, all document versions are deleted, and the content of all document versions are moved.
Method for deleting all the versions of a document from FileNet
public void deleteDocumentFromCE(String filenetDocGUID) throws Exception
{
System.out.println("In deleteDocumentFromCE() method");
System.out.println("Input Parameter filenetDocGUID is : " + filenetDocGUID);
Document document = null;
UserContext uc = null;
ObjectStore os = null;
Subject subject = null;
VersionSeries vs = null;
try
{
if (filenetDocGUID != null)
{
getCESession(); //This method will get the CE session and set it in ceSessionData private class variable
os = ceSessionData.getObjectStore();
System.out.println("ObjectStore fetched from CESession static reference is : " + os.get_Name());
subject = ceSessionData.getSubject();
System.out.println("Subject fetched from CESession static reference.");
uc = UserContext.get();
uc.pushSubject(subject);
if (os != null)
{
document = Factory.Document.fetchInstance(os, filenetDocGUID, null);
vs = document.get_VersionSeries();
vs.delete();
vs.save(RefreshMode.NO_REFRESH);
System.out.println("All Document Versions deleted : " + filenetDocGUID);
}
else
{
System.out.println("Error :: Object Store is not available.");
}
}
}
catch (Exception e)
{
System.out.println("Exception in deleteDocumentFromCE() Method : "+ e.getMessage());
//pass the error to the calling method
throw new Exception("System Error occurred while deleting the document in CE.. "+e.getMessage());
}
finally
{
if (uc != null)
uc.popSubject();
}
System.out.println("End of deleteDocumentFromCE() method");
}
i want to put if else or switch statement which is more suitable for checking employee count before commit.where i put my if else or switch code . i want restriction on employee if count is 5 then its show message "reached maximum employee limites" otherwise allow commit.
i am new in java plz someone help me to solve this
public String cmdSave_action()
{
// my code before
{
DeptSet result;
try {
dbo.connect();
result =
dbo.execSQL("select count(*) from empmasterinfo where mainid='ORGElement' and designationid='?') "
(inputText_ORGElement.getValue() != null ?
""));
result = dbo.execSQL(sSQL);
catch (Exception e) {
System.out.println(e.getMessage());
finally
{
dbo.close();
}
return null;
}}}
// my code above
{
Global.PerformIteratorAction(this.bindings, "Commit");
AdfFacesContext afContext = AdfFacesContext.getCurrentInstance();
afContext.getProcessScope().put("EmployeeID",
Global.getCurrRowFieldValue("EmpmasterinfoViewIterator",
"Employeeid"));
if (afContext.getProcessScope().get("AddEdit").toString().equals("0"))
{
Global.PerformIteratorAction(this.bindings,
"EPR_TRANSFER_APPLICANT_INFO");
Global.PerformIteratorAction(this.bindings, "eprGenerateApPlan");
}
return null;
}}
My Error Log
Error(149,12): 'try' without 'catch' or 'finally'
Error(154,36): , expected
Error(157,34): field SQL not found in class hcm.view.backing.empprofile.EmployeeMasterInfo_Add
Error(159,11): illegal start of expression
Error(159,11): ; expected
E:\HCM\ViewController\src\hcm\view\backing\empprofile\dbo.java
Error(13,16): method does not return a value
Please close Your try catch block properly
try{
}catch(Exception e){
}finally{
}
And Read this
catch and finally are within try block
try {
//code
}
catch(Exception e) {
System.out.println(e.getMessage());
}
finally {
dbo.close();
}
Using an IDE will help you with indentation and proper formatting while writing code. e.g Eclipse.
For the first error close the try-catch blocks properly
And for the second error: Since your method is declared as public String cmdSave_action(), you should return a String value at the end of the method. The return statement is missing in your code.
I have a OneToOne relationship between two tables, as shown below:
PreRecordLoad.java:
#OneToOne(mappedBy="preRecordLoadId",cascade = CascadeType.ALL)
private PreRecordLoadAux preRecordLoadAux;
PreRecordLoadAux.java:
#JoinColumn(name = "PRE_RECORD_LOAD_ID", referencedColumnName = "PRE_RECORD_LOAD_ID")
#OneToOne
private PreRecordLoad preRecordLoadId;
I'm using this method to pull back the PreRecordLoad object:
public PreRecordLoad FindPreRecordLoad(Long ID)
{
print("Finding " + ID + "f");
Query query;
PreRecordLoad result = null;
try
{
query = em.createNamedQuery("PreRecordLoad.findByPreRecordLoadId");
query.setParameter("preRecordLoadId", ID);
result = (PreRecordLoad)query.getSingleResult();
//result = em.find(PreRecordLoad.class, ID);
}
catch(Exception e)
{
print(e.getLocalizedMessage());
}
return result;
}
The '+ "f"' is to see if the passed value somehow had something at the end. It didn't.
I originally used em.find, but the same issue occurred no matter which method I used.
I used to use a BigDecimal for the ID because it was the default, and noticed I was getting a precision difference when it worked, and when it didn't work. Specifically the precision was 4 when it didn't work, but 0 when it did. I couldn't work out why this was, so I changed the BigDecimal to a Long, as I never really needed it to be a BigDecimal anyway.
When I save the new PreRecordLoad and PreRecordLoadAux objects to the database (inserting them for the first time), and then try and run this method to recall the objects, it retrieves the PreRecordLoad, but the PreRecordLoadAux is null. This is despite the entry being in the database and what looks to be full committed, as I can access it from SQLDeveloper, which is a separate session.
However, if I stop and re-run the application, then it successfully pulls back both objects. The ID being passed is the same both times, or at least appears to be.
Anyway suggestions would be greatly appreciated, thankyou.
Edit:
Here is the code for when I am persisting the objects into the DB:
if(existingPreAux==null) {
try {
preLoad.setAuditSubLoadId(auditLoad);
em.persist(preLoad);
print("Pre Record Load entry Created");
preAux.setPreRecordLoadId(preLoad);
em.persist(preAux);
print("Pre Record Load Aux entry Created");
}
catch(ConstraintViolationException e) {
for(ConstraintViolation c : e.getConstraintViolations()) {
System.out.println (c.getPropertyPath() + " " + c.getMessage());
}
}
}
else {
try {
preLoad.setPreRecordLoadId(existingPreLoad.getPreRecordLoadId());
preLoad.setAuditSubLoadId(auditLoad);
em.merge(preLoad);
print("Pre Record Load entry found and updated");
preAux.setPreRecordLoadAuxId(existingPreAux.getPreRecordLoadAuxId());
preAux.setPreRecordLoadId(preLoad);
em.merge(preAux);
print("Pre Record Load Aux entry found and updated");
}
catch(ConstraintViolationException e) {
for(ConstraintViolation c : e.getConstraintViolations()) {
System.out.println (c.getPropertyPath() + " " + c.getMessage());
}
}
}
That's in a method, and after that code, the method ends.
It's your responsibility to maintain the coherence of the object graph. So, when you do preAux.setPreRecordLoadId(preLoad);, yo must also do preLoad.setPreRecordLoadAux(preAux);.
If you don't, then every time you'll load the preAux from the same session, it will be retrieved from the first-level cache, and will thus return your incorrectly initialized instance of the entity.
I am having a LDAP Queue which process a object class.I cant find the exact location why it is giving the exception. The objclass is a concadenation string with pipe symbol. Any program coding to find the exact location in which concadination part is going to the Exception?.Please Assist.
try {
Attributes objClass = null;
try {
objClass = getObjClass(LdapInfo.PER_ID, person.perId);
} catch (NamingException e)
{
DCXError.myInstance().writeError("LdapUpdaterConnection: " + e.getMessage());
}
NamingEnumeration oc = objClass.get("objectclass").getAll();
String baseObjClass = null;
while (oc.hasMoreElements()) {
baseObjClass = (String) oc.nextElement();
if (baseObjClass.equalsIgnoreCase(LdapInfo.NON_EMPLOYEE_PERSON)
|| baseObjClass.equalsIgnoreCase("N/A")||
baseObjClass.equalsIgnoreCase(LdapInfo.EMPLOYEE_PERSON))
break;
}
} catch (SchemaViolationException e4) {
DCXError.myInstance().writeError(
"LdapUpdaterConnection:doUpdate SchemaViolationException "+ e4.getExplanation());
DCXError.myInstance().writeError("LdapUpdaterConnection:update persID = " + personId);
return (LdapUpdaterConnection.BAD_DATA);
}
You can't find the exact location only because you haven't logged the stack trace. You would also need to reformat your code so that each statement is on a separate line to make any use of that information. You should also use variable names that actually correspond to the content.
This is really terrible code.
It's also hard to see why you are doing all this in the first place. A decent query filter would do all that for you far more simply.