Item Property throws NullPointer Exception

Vaadin 6 / 7 / 8
1

Hello,

when I user the container.addItem() method to add a new Item, all properties of this newly added Item are null, which is correct. But how can I set the values of these properties then? I tried to make it like this:

dataItem.getItemProperty("GLN").setValue(gln.getValue().toString()); This causes a ​java.lang.NullPointerException Because the ItemProperty GLN is null at this point, which shows the Log:

ID:1|ID_ABBRECHNUNG:1|GLN:null How can I set properties of new Items?

2

Hi,
depending on the container type you can use

addContainerProperty(java.lang.Object propertyId, java.lang.Class<?> type, java.lang.Object defaultValue) For example it will work with IndexedContainer but not with BeanItemContainer.
What kind of container are you using?

3

Hi,

the property already exists, so adding it is not an option I guess. The value of the property is null, and that is keeping me from setting a value. Which is weird in my opinion…

4

To better understand the problem can you please post some more code, like container initialization and how do you use it?

From your code I can only guess that the null pointer can be given from a missing property (not value) in the container or by a null value in return of gln.getValue()

5

Okay, here is some more code. But before you read the code pls note that this is the outcome of System.out.println(item):

ID:1|ID_ABBRECHNUNG:1|GLN:null|UST:null|STEUERNUMMER:null|HANDELSREGISTER:null|ZAHLUNGSART:null|KONTOR_GLN:null|KIN:null|ZAHLUNGSZIEL:null All properties are listed, so that’s why I assume that there are all the properties.

Here is the container initialization and all the other stuff:

TableQuery tqAbre = new TableQuery("DE_BPM_LIST_TEST_ABRE", pool, new OracleGenerator());
container = new SQLContainer(tqAbre);
Object newObj = container.addItem();
dataItem = container.getItem(newObj);
dataItem.getItemProperty("GLN").setValue(gln.getValue().toString());
container.commit();

Please note that reading data is not a problem and that writing is not a problem either as long as the attributes/properties are not null, which is the case after creating a new row in the database…

6

Ok, thank you for clarification.
And I suppose the stacktrace indicates that the NullPointer is thrown exactly on the following row (not on some other method/class involved in setValue ), right?

dataItem.getItemProperty("GLN").setValue(gln.getValue().toString()); If so, the only thing I can figure out is that gln.getValue() return null, so then call to toString() is the cause of the NullPointer.

HTH
Marco

7

Okay I figured it out. I fetched all Items and looped through them to pick the last one out (The query can just return one Item at any point) and then wrote this into a variable for later use. Somehow that doesn’t so I had to move the code into the loop. Is there any better way to manage this? Like a method which just returns one single item? This is how it is implented at the moment:

At least it works this way and it is not really an issue since the programm needs to go through the loop only once:

//Initialization of the Container
DBService dbService = new DBService();
SQLContainer container = dbService.getContainerLogistik();

//Adding the filter
container.addContainerFilter(new Like("ID_ACC", loggedInUser.getUser().getItemProperty("ID_ACC").getValue().toString()));
            
//Loop through all items
Collection c = container.getItemIds();
if(c.size() > 0) {
   for (Iterator i = c.iterator(); i.hasNext();) {
       Item dataItem = container.getItem(i.next());
                    
       //Set the properties
       if(regellieferzeit.getValue() != null) {
          dataItem.getItemProperty("REGELLIEFERZEIT").setValue(regellieferzeit.getValue().toString());
       }
       if(regellieferzeitAktion.getValue() != null) {
          dataItem.getItemProperty("REGELLIEFERZEIT_AKTION").setValue(regellieferzeitAktion.getValue().toString());
       }
    }
}
container.commit();
8

Maybe you can use container.lastItemId()

if (c.size()  > 0) {
    Item dataItem = container.getItem(container.lastItemId())
    ...
}

HTH
Marco

9

The Javadoc for addItem() mentions this:

* Note! If auto commit mode is enabled, this method will still return the * temporary row ID assigned for the item. Implement * QueryDelegate.RowIdChangeListener to receive the actual Row ID value * after the addition has been committed. In your code it seems you are using the temporary ID.