I am using spring batch to read pipe (| delimited) separated file which have have 7 field. I created a class called MyLineMapper that extends spring's FieldSetMapper. This class maps field values provided in file to my object (XYZ type). Now the problem is that fieldSet object that i get inside class extending FieldSetMapper contain empty value for field that are not present in delimited values.
For example:
Suppose that the delimited file format is as follows: |ID|Country|City|Pin|
Suppose i provide following line in file: |1|India|
As you can see the above line does not contain information for City and Pin. Therefore, I expect FieldSet object should contain Null value for these two fiels (City and Pin) instead of empty string. I don't want empty value as Null will help me to know if that field was actually present in file or not.
How can I achieve this ? Do I need to extend DelimitedLineTokenizer which I am using for tokenizing ? Or this is a simple way to do this ?
Any help will be appreciated.
From FieldSetMapper javadoc
To customize the way that FieldSet values are converted to the desired
type for injecting into the prototype there are several choices. You
can inject PropertyEditor instances directly through the customEditors
property, or you can override the createBinder(Object) and
initBinder(DataBinder) methods, or you can provide a custom FieldSet
implementation.
Depending on type of your target bean conversion is done using default Spring convention. If you need other type of logic write your own.
Related
Final goal: create a custom editor that will let me select from a list of types and then enter additional parameters specific to that type.
To this end, I have created a pure data type, let's call it BasicData, with a SpecificData parameter of an abstract base type, let's call it ExtraData. The idea is to have the type information in BasicData (enum value), and then populate the SpecificData field in the custom editor code so that when I change selection a new object from a class derived from ExtraData. Then its values can be further edited by additional fields created for that specific type, as shown here.
I started doing the above, but I ran into problems trying to get the actual object being edited in order to set the SpecificData property. My classes are not Unity objects or scripts, and I'd rather not turn them into such just for this. I might be able to use reflection to do this but then changes in the editor won't take effect while it runs, from what I understand.
What is the best way to accomplish this?
I have a class named "Project" with attribute "Name" having type of String. I have changed it from Allow Null=True to False and then I have saved the model and restarted the WECPOF prototyper in xml mode. But it still allows me to create and save instances of Project without adding a name. What might I be doing wrong?
Try to keep your attributes "nullable", i.e. Allow null = True. Why? Because you usually end up wanting to see the difference between "nothing" and "empty".
As Hans suggested, add a contraint on the class with a expression like this "not self.Name.isNullOrEmpty".
I guess the string is not null but empty "". Strings are tricky that way - the only type that is presented the same as null and as its simplest possible value.
To signal to user that you do not allow a null or empty you can do a constraint on the class or add a validation expression in the ViewModel.
I've two classes (A and B) that extend a base class BASE. I need to make a report that takes an array of such classes and the prints the fields of A or B. I tought of using conditional expressions, then casting to one or another (depending on a field value). But I can't cast, because I don't know how to refere to the current bean.
To do this I am using a JRBeanCollectionDataSource filled with a List<BASE>. How do I cast every bean to A or B in a report (or subreport)? I tried:
((A)this)
but it says basically that this contains the report instance, not the current bean and gives error.
use ((A) BASE) suppose BASE is your BASE class
now BASE point to the current record
I am using Dozer mapping. i have two pojo1 and pojo2. pojo1 values to be mapped to pojo2. Pojo1 has 3 properties and Pojo2 has 4 properties. i am able to map 3 properties form pojo1 to pojo2 but to map fourth property i dont have property in pojo1. to map fourth property i cannot take value from pojo1, directly i need to give the value by taking from Enum. Please help me is it possible to give value to any property through mapping file?
value from enum directly not from pojo1
fourth property
Thanks!
As far as I know this is not possible in a convenient way. The only way to do this atm is by either having a custom converter, or by modifying one of the POJOs.
With a custom converter you could just map pojo1.field3 to pojo2.field4. The converter completely ignores pojo1.field3, and just sets the pojo2.field4 to your enum value.
Another solution is to just modify pojo1 and add a field4 which always returns the enum value.
And the third solution is to modify pojo2, and just set field4 in the default constructor. If you can't modify the default constructor, you can use a custom create method or a custom bean factory to achieve the same.
I've been doing dozer mappings a lot, and would like some more convenient solution for this too. Unfortunately I don't think there is any atm.
Let me know how it works out for you!
I have a little bit of a curve ball for you. Maybe just a design issue...maybe even something as simple as me not understanding Data annotation providers.
Anyway here we go:
I have a class which represents some model data. Let's say it represents a package/box/carton.
It actually represents all of these things so I use the class in several different views. Sometimes I want the attribute of the field Package_Description to be
So that it shows up as Box Number : input box here.
Now if i want it to appear as "Carton Name" my only option would be to sub type it. Or use a separate class to have the annotations for this class. My quandary is that some of the field names are user configurable and therefore I cannot have a static definition!
(By the way i am using third party librarys [Telerik MVC Grid] do display these field names so i cannot change the fact that it's looking at data annotation )
So I just need to know is there a way to add attributes dynamically?
Create an anonymous type on the fly, sub class the original and then add attributes using reflection?
Or what other options are open to me, do I need to somehow implement a different annotation provider?
Attributes are part of the definition of the type. Because of that, you can't modify attributes of existing classes during runtime.
You could create a new type during runtime (not an anonymous type), but I think that's not such a good idea. I'm sure whatever component you're using, it allows you to specify the appearance explicitly.