When to use Singleton Node?

[Former Member]

Hi,

I read some online documentation, understood below point. When these is a nested nodes and you want see auto change of elements in child node based on element(lead selection) changed in parent node(one level above one).

There are two type of possibilities to use nested nodes.

(A) Header data(table), & Item data(table)

(B) Tree type reports.

Correct me if I were wrong.

1. What will happen if I do not use 'Singleton' property?

2. Can you explain me when do I need to use Singleton property?

3. How Component Configuration will help you?

Regards,

Meera.

[sahai]

hi meera,

In general, dependent nodes are represented by a single node instance, whose content u2013 that is, its data collection - changes each time the lead selection of the parent node changes. This is known as a singleton node. The representation of a single node instance reduces the required resources considerably. This improves the performance of the application significantly. However, the use of singleton nodes also results in programming restrictions. This means that the user can only access data of child nodes whose parent nodes have the lead selection. Consequently, you cannot read - for example - the address fields of a business partner X if the business partner Y is selected. Each modification of the parent node lead selection causes a data modification of the singleton child node.

Therefore, Web Dynpro allows you to define additional non-singleton nodes. Each non-singleton node has one node instance for each node element of the parent collection at runtime. The advantage is that each instance can be accessed directly. When using non-singleton nodes, the nodes are only created when the node values are retrieved. This can save resources that otherwise would slow down the performance of the application.

Note that singleton nodes should only be considered singleton in relation to their parent nodes but not in relation to the context. Each instance of a non-singleton parent node has exactly one instance of the singleton node.

hope you will get answers for your questions once you read the above

regards,

sahai.s

Edited by: sahai.s on Jan 24, 2011 10:40 AM