I'm trying to run a simple Test with Esper (Chapter 14, http://dl.e-book-free.com/2013/07/activiti_in_action.pdf). The code is pretty simple:
public class EventLengthWindowTest {
public class LoanRequestEvent {
public int amount =2;
public LoanRequestEvent(int a){
amount += a;
}
}
private int sumAmount = 0;
#Test
public void testEventLengthWindow() {
Configuration configuration = new Configuration();
configuration.addEventType(LoanRequestEvent.class);
EPServiceProvider epService = EPServiceProviderManager.getDefaultProvider(configuration);
EPAdministrator admin = epService.getEPAdministrator();
EPStatement epStatement = admin.createEPL("select sum(amount) as sumAmount from LoanRequestEvent.win:length(2)");
...
}
I get an error message regarding the EPL part:
"select sum(amount) as sumAmount from LoanRequestEvent.win:length(2)"
It says:
com.espertech.esper.client.EPStatementException: Error starting statement: Failed to validate select-clause expression 'sum(amount)': Property named 'amount' is not valid in any stream [select sum(amount) as sumAmount from LoanRequestEvent.win:length(2)]
Any ideas why this happens?
You need to provide JavaBean getters and setters for the event properties in your event classes if you want Esper to read and/or write to them. For your example to work, you need to add a getter like this:
public class LoanRequestEvent {
public int amount =2;
public LoanRequestEvent(int a){
amount += a;
}
public int getAmount() {
return amount;
}
}
Related
Taking a reference from link: Postgres to fetch the list having comma separated values, I want to write a query which somhow brings Employee email Table fields as a list for a particular Empployee. This is needed for Spring Batch to Simply match it from the Resultset and create a POJO/Model class like List emails for Employee class?
Can this be possible ?
select c.*, ce.*, string_agg(ce.email, ',') as emails
from root.employee c
full outer join root.employee_email ce
on c.employee_id = ce.employee_id
group by
c.employee_id, ce.employee_email_id
order by
c.employee_id
limit 1000
offset 0;
Your problem is a common one in the batch processing realm and with Spring Batch it is called "Driving Query Based ItemReaders", you can find more about that in here.
Basically you retrieve the Contacts in your reader, and in your processor you add the list of Emails to them.
#Bean(destroyMethod = "")
public JdbcCursorItemReader<Employee> employeeReader(DataSource dataSource) {
JdbcCursorItemReader<Employee> ItemReader = new JdbcCursorItemReader<>();
ItemReader.setDataSource(dataSource);
ItemReader.setSql("SELECT * FROM employee.employee C ");
ItemReader.setRowMapper(new EmployeeRowMapper());
return ItemReader;
}
#Bean
public ItemProcessor<Employee, Employee> settlementHeaderProcessor(JdbcTemplate jdbcTemplate){
return item -> {
root.EMPLOYEE_EMAIL CE WHERE ce.employee_id = ? ",
new Object[]{item.getId()},
new RowMapper<String>() {
#Override
public String mapRow(ResultSet resultSet, int i) throws SQLException {
return resultSet.getString("EMAIL");
}
});
item.setEmails(emails);
return item;
};
}
PS : this could have some performance issues if you have lots of contacts, because for each contact Item you will hit the database to retrieve Emails.
There is another optimized way, by creating a custom reader that will return a List of Contacts (For example 1000 by 1000), and a processor that will enrich them with their emails. This way you will hit the database again for each 1000 Contact Item.
In your reader your retrieve a list of unique Employees page per page (Say your page is 1000 long).
And in your processor for the 1000 employees you retrieve all their emails in one query.
Then for each employee you set the emails retrieved in the last query.
An example might like the following:
public interface EmployeeRepository extends PagingAndSortingRepository<Employee, Integer> {
}
#Getter
class EmployeeVO {
private Long employeeId;
private String email;
EmployeeVO(Long employeeId, String email) {
this.employeeId= employeeId;
this.email = email;
}
}
public class EmployeeListReader implements ItemReader<List<Employee>> {
private final static int PAGE_SIZE = 1000;
private final EmployeeRepository employeeRepository;
private int page = 0;
public EmployeeListReader(EmployeeRepository employeeRepository) {
this.employeeRepository = employeeRepository;
}
public List<Employee> read() throws Exception {
Page<Employee> employees = employeeRepository.findAll(PageRequest.of(page, PAGE_SIZE));
page++;
return employees.getContent();
}
}
#Bean
EmployeeListReader reader(){
return new EmployeeListReader(this.employeeRepository);
}
#Bean
public ItemProcessor<List<Employee>, List<Employee>> settlementHeaderProcessor(NamedParameterJdbcTemplate namedParameterJdbcTemplate) {
return item -> {
List<Long> employeesIds = item.stream().map(Employee::getId).collect(Collectors.toList());
SqlParameterSource parameters = new MapSqlParameterSource("ids", employeesIds);
List<ContactVO> emails = namedParameterJdbcTemplate
.query("SELECT CE.employeeId, CE.EMAIL FROM employee_EMAIL CE WHERE ce.contact_id IN (:ids) ",
parameters,
new RowMapper<ContactVO>() {
#Override
public ContactVO mapRow(ResultSet resultSet, int i) throws SQLException {
return new ContactVO(
resultSet.getLong("EMPLOYEE_ID"),
resultSet.getString("EMAIL"));
}
});
Map<Long, List<ContactVO>> emailsByContactId = emails.stream().collect(Collectors.groupingBy(ContactVO::getContactId));
List<Employee> newEmployeesWithEmails = Collections.unmodifiableList(item);
newEmployeesWithEmails.forEach(employee -> {
employee.setEmails(emailsByContactId.get(employee.getId()).stream().map(ContactVO::getEmail).collect(Collectors.toList()));
});
return newEmployeesWithEmails;
};
}
Hope this helps
I'm trying to use a DateTime LastModifiedDate column with optimistic concurrency in Entity Framework (will likely upgrade it to DateTime2.) I've set the Concurrency Mode to Fixed. But when I retrieve an entity, change a column and try to save, get a concurrency exception.
The stored LastModifiedDate is 2017-01-04 21:16:55.283 but look at the SQL Entity Framework is generating for the update:
UPDATE [dbo].[Facilities]
SET [Password] = #0
WHERE (([pk_FacilityID] = #1) AND ([LastModifiedDate] = #2))
-- #0: 'bz0dkK+smlat9psrIrbyXkxjpcXcDK1DeUiha7jCRkU=' (Type = String, Size = 255)
-- #1: '6801bdcf-266d-46bd-b15e-dac21116208d' (Type = Guid)
-- #2: '1/4/2017 9:16:55 PM' (Type = DateTime2)
Notice it's passing a formatted DateTime string for #2 which does not include milliseconds. Well of course it doesn't match if it's not passing in the same value it retrieved! I've verified that at runtime, the .NET DateTime does include the 0.283 seconds. Please tell me there's a way to pass in the full value. Why does it behave this way and how can I change it to include milliseconds?
-- #2: '1/4/2017 9:16:55 PM' (Type = DateTime2)
That's not the actual parameter value sent. That's just the logging, and it leaves off the fractional seconds. There is a problem, but that's not it.
If you profile you should see something like this, that shows the details of the parameter type and value.
exec sp_executesql N'UPDATE [dbo].[Facilities]
SET [Name] = #0
WHERE (([FacilityId] = #1) AND ([LastModified] = #2))
',N'#0 nvarchar(max) ,#1 int,#2 datetime2(7)',#0=N'newName',#1=1,#2='2017-08-31 15:45:55.3030000'
What's happening is the datetime2(7) value is not round-trip converting to and back from datetime. And the easiest fix is just to use datetime2(7) for your table column. If you want to use the column for optimistic concurrency control, you need the extra precision anyway.
So something like this:
using System;
using System.Linq;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
namespace Ef6Test
{
public class Facility
{
public int FacilityId { get; set; }
public string Name { get; set; }
[ConcurrencyCheck(),Column(TypeName ="datetime2")]
public DateTime LastModified { get; set; }
}
class Db : DbContext
{
public DbSet<Facility> Facilities { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
}
}
class Program
{
static void Main(string[] args)
{
Database.SetInitializer(new DropCreateDatabaseAlways<Db>());
using (var db = new Db())
{
var f = db.Facilities.Add(new Facility() { LastModified = DateTime.Now, Name = "Faclity1" });
db.SaveChanges();
}
using (var db = new Db())
{
var f = db.Facilities.First();
f.Name = "newName";
db.SaveChanges();
}
Console.ReadKey();
}
}
}
the Get(string _date) method below does not work. I get the following exception. I know EFCore is very limited but this exception does not help to see where the problem is exactly at. Can you please explain me what's causing this exception?
An unhandled exception occurred while processing the request.
ArgumentException: The given expression 'new EntryViewModel([x])' does not contain the searched expression '[x]' in a nested NewExpression with member assignments or a MemberBindingExpression.
Parameter name: fullExpression
InvokeMethod
TargetInvocationException: Exception has been thrown by the target of an invocation.
InvokeMethod
EntryController.cs
[HttpGet("{_date}")]
public async Task<IEnumerable<EntryViewModel>> Get(string _date)
{
DateTime date = DateTime.ParseExact(_date, "dd-MM-yyyy", CultureInfo.InvariantCulture);
User user = await _userManager.GetUserAsync(HttpContext.User);
var Entries = _context.Entries.Include(x => x.Budget)
.Where(x => x.User.Id == user.Id && x.Date >= date && x.Date < date.AddDays(7))
.Select(x=> new EntryViewModel(x))
.ToList();
return Entries;
}
EntryViewModel.cs
public class EntryViewModel
{
public int Id { get; set; }
public int BudgetId { get; set; }
public string Date { get; set; }
public int Duration { get; set; }
public string UserId { get; set; }
public EntryViewModel(Entry entry)
{
Id = entry.Id;
BudgetId = entry.BudgetId;
Date = entry.Date.ToString("dd-MM-yyyy", CultureInfo.InvariantCulture);
Duration = entry.Duration;
UserId = entry.UserId;
}
}
What this cryptic exception message is saying is that in EF, if you want to use x to construct a new object, it must be in the form new C { A = x.B, ... } (where C may be omitted to project to an anonymous type). EF does not support calling arbitrary functions (including constructors), only some specific functionality such as calling property setters is supported.
You can try as shown below then and let us know about the result.
var Entries = _context.Entries.Include(x => x.Budget)
.Where(x => x.User.Id == user.Id && x.Date >= date && x.Date < date.AddDays(7))
.Select(e=> new EntryViewModel
{
BudgetId=e.BudgetId,
Duration=e.Duration,
}).ToList();
Try adding AsNoTracking() to your query if you have no write
I'm using EclipseLink to run some Native SQL. I need to return the data into a POJO. I followed the instructions at EclipseLink Docs, but I receive the error Missing descriptor for [Class]
The query columns have been named to match the member variables of the POJO. Do I need to do some additional mapping?
POJO:
public class AnnouncementRecipientsFlattenedDTO {
private BigDecimal announcementId;
private String recipientAddress;
private String type;
public AnnouncementRecipientsFlattenedDTO() {
super();
}
public AnnouncementRecipientsFlattenedDTO(BigDecimal announcementId, String recipientAddress, String type) {
super();
this.announcementId = announcementId;
this.recipientAddress = recipientAddress;
this.type = type;
}
... Getters/Setters
Entity Manager call:
public List<AnnouncementRecipientsFlattenedDTO> getNormalizedRecipientsForAnnouncement(int announcementId) {
Query query = em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT, AnnouncementRecipientsFlattenedDTO.class);
query.setParameter(1, announcementId);
return query.getResultList();
}
I found out you can put the results of a Native Query execution into a List of Arrays that hold Objects. Then one can iterate over the list and Array elements and build the desired Entity objects.
List<Object[]> rawResultList;
Query query =
em.createNamedQuery(AnnouncementDeliveryLog.FIND_NORMALIZED_RECIPIENTS_FOR_ANNOUNCEMENT);
rawResultList = query.getResultList();
for (Object[] resultElement : rawResultList) {
AnnouncementDeliveryLog adl = new AnnouncementDeliveryLog(getAnnouncementById(announcementId), (String)resultElement[1], (String)resultElement[2], "TO_SEND");
persistAnnouncementDeliveryLog(adl);
}
You can only use native SQL queries with a class if the class is mapped. You need to define the AnnouncementRecipientsFlattenedDTO class as an #Entity.
Otherwise just create the native query with only the SQL and get an array of the data back and construct your DTO yourself using the data.
Old question but may be following solution will help someone else.
Suppose you want to return a list of columns, data type and data length for a given table in Oracle. I have written below a native sample query for this:
private static final String TABLE_COLUMNS = "select utc.COLUMN_NAME, utc.DATA_TYPE, utc.DATA_LENGTH "
+ "from user_tab_columns utc "
+ "where utc.table_name = ? "
+ "order by utc.column_name asc";
Now the requirement is to construct a list of POJO from the result of above query.
Define TableColumn entity class as below:
#Entity
public class TableColumn implements Serializable {
#Id
#Column(name = "COLUMN_NAME")
private String columnName;
#Column(name = "DATA_TYPE")
private String dataType;
#Column(name = "DATA_LENGTH")
private int dataLength;
public String getColumnName() {
return columnName;
}
public void setColumnName(String columnName) {
this.columnName = columnName;
}
public String getDataType() {
return dataType;
}
public void setDataType(String dataType) {
this.dataType = dataType;
}
public int getDataLength() {
return dataLength;
}
public void setDataLength(int dataLength) {
this.dataLength = dataLength;
}
public TableColumn(String columnName, String dataType, int dataLength) {
this.columnName = columnName;
this.dataType = dataType;
this.dataLength = dataLength;
}
public TableColumn(String columnName) {
this.columnName = columnName;
}
public TableColumn() {
}
#Override
public int hashCode() {
int hash = 0;
hash += (columnName != null ? columnName.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object object) {
if (!(object instanceof TableColumn)) {
return false;
}
TableColumn other = (TableColumn) object;
if ((this.columnName == null && other.columnName != null) || (this.columnName != null && !this.columnName.equals(other.columnName))) {
return false;
}
return true;
}
#Override
public String toString() {
return getColumnName();
}
}
Now we are ready to construct a list of POJO. Use the sample code below to construct get your result as List of POJOs.
public List<TableColumn> findTableColumns(String table) {
List<TableColumn> listTables = new ArrayList<>();
EntityManager em = emf.createEntityManager();
Query q = em.createNativeQuery(TABLE_COLUMNS, TableColumn.class).setParameter(1, table);
listTables = q.getResultList();
em.close();
return listTables;
}
Also, don't forget to add in your POJO class in persistence.xml! It can be easy to overlook if you are used to your IDE managing that file for you.
Had the same kind of problem where I wanted to return a List of POJOs, and really just POJOs (call it DTO if you want) and not #Entity annotated Objects.
class PojoExample {
String name;
#Enumerated(EnumType.STRING)
SomeEnum type;
public PojoExample(String name, SomeEnum type) {
this.name = name;
this.type = type;
}
}
With the following Query:
String query = "SELECT b.name, a.newtype as type FROM tablea a, tableb b where a.tableb_id = b_id";
Query query = getEntityManager().createNativeQuery(query, "PojoExample");
#SuppressWarnings("unchecked")
List<PojoExample> data = query.getResultList();
Creates the PojoExample from the database without the need for an Entity annotation on PojoExample. You can find the method call in the Oracle Docs here.
edit:
As it turns out you have to use #SqlResultSetMapping for this to work, otherwise your query.getResultList() returns a List of Object.
#SqlResultSetMapping(name = "PojoExample",
classes = #ConstructorResult(columns = {
#ColumnResult(name = "name", type = String.class),
#ColumnResult(name = "type", type = String.class)
},
targetClass = PojoExample.class)
)
Just put this anywhere under your #Entity annotation (so in this example either in tablea or tableb because PojoExample has no #Entity annotation)
I have a model called 'UserRoleHolder' like below.
#Entity
public class UserRoleHolder extends Model implements RoleHolder {
private static final long serialVersionUID = 1L;
#EmbeddedId
public UserRoleHolderPK userRoleHolderPK;
public List<UserPermission> permissions;
public List<UserRole> roles;
....
I made a composite PK called UserRoleHolderPK and it contains two foreign keys like below.
#Embeddable
public class UserRoleHolderPK {
#Basic
public Long userId;
#Basic
public Long projectId;
public UserRoleHolderPK(Long userId, Long projectId) {
this.userId = userId;
this.projectId = projectId;
}
public boolean equals(Object object) {
if (object instanceof UserRoleHolderPK) {
UserRoleHolderPK userRoleHolderPK = (UserRoleHolderPK) object;
return userId == userRoleHolderPK.userId && projectId == userRoleHolderPK.projectId;
} else {
return false;
}
}
public int hashCode() {
return (int) (userId + projectId);
}
}
userId and projectId are from other Models. (User.java and Project.java)
Then, in 'UserRoleHolder' class, I made a method called 'findRolesById' like below.
public static List<? extends Role> findRolesById(Long userId, Long projectId) {
return find
.where()
.eq("userRoleHolderPK", new UserRoleHolderPK(userId, projectId))
.findUnique().roles;
}
However, when I tried to run a test code like below, I encountered serious errors.
#Test
public void findRolesById() {
// Given
// When
#SuppressWarnings("unchecked")
List<UserRole> list = (List<UserRole>) UserRoleHolder.findRolesById(1l, 1l);
// Then
assertThat(list.get(0).name).isEqualTo("manager");
}
Errors are like,
'Syntax error in SQL statement "SELECT T0.USER_ID C0, T0.PROJECT_ID C1 FROM USER_ROLE_HOLDER T0 WHERE T0.NULL[*] = ? "; expected "identifier"; SQL statement: select t0.user_id c0, t0.project_id c1 from user_role_holder t0 where t0.null = ? [42001-158]
Bind values:[null]
Query was:
select t0.user_id c0, t0.project_id c1 from user_role_holder t0 where t0.null = ?
I think I missed some serious and basic stuff when I used JPA. Please, let me know what is the problem.
I think your problem is that you are trying to compare the Embeddedid object and not its fields, I don't think that the program will be smart enough as to know how to convert an user object comparison (the equals) to sql, so you might want to try something like this:
public static List<? extends Role> findRolesById(Long userId, Long projectId) {
return find
.where()
.eq("userRoleHolderPK.userId", userId)
.eq("userRoleHolderPK.projectId", projectId)
.findUnique().roles;
}