I have a one-to-many Category-Products relation:
public class **Category**{
@Version
private Integer version;
@OneToMany(mappedBy = "category", cascade = {CascadeType.ALL})
//@OptimisticLock(excluded = true)
private List<Product> products
....
}
and the many-to-one side:
public class **Product**{
@Version
private Integer version;
@ManyToOne
@JoinColumn(name = "category_id")
@ForeignKey(name = "fk_category_product")
//@OptimisticLock(excluded = true)
private Category category
....
}
I want to prevent Lost Modifications, so I defined a version mechanism (concurrency control) as above.
But when I want to save my parent entity(Category), I get the following error:
could not execute statement; SQL [n/a]; constraint [JOHN.SYS_C0090239]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
Here is my Action, service and dao layers:
Action
public String save() throws Exception {
try {
categoryManager.saveCategory(category);
}catch (CategoryExistException e){
List<Object> args = new ArrayList<Object>();
args.add(category.getCategoryName());//categoryName is UNIQUE
addActionError(getText("errors.existing.category", args));
return INPUT;
}
}
Manager
@Override
public Category saveCategory(Category category) throws CategoryExistException{
if (category.getVersion()==null)
{
// if new category, lowercase categoryId
category.setCategoryName(category.getCategoryName().toLowerCase());
}
try {
return categoryDao.saveCategory(category);
} catch (final Exception e) {
e.printStackTrace();
log.warn(e.getMessage());
throw new CategoryExistException("Category '" + category.getCategoryName() + "' already exists!");
}
}
Dao
@Override
public Category saveCategory(Category category){
if (log.isDebugEnabled()) {
log.debug("category's id: " + category.getCategoryId());
}
getSession().saveOrUpdate(category);
//getSession().merge(category);
// necessary to throw a DataIntegrityViolation and catch it in CategoryManger
getSession().flush();
return category;
}
