What is Lead Selection,cardinality,singleton,

[Former Member]

Hi.i am very new to SAP Webdynpro..can any one help me in explaining what is

Lead Selection,cardinality,singleton,

thanks

Ravi

[Former Member · Accepted solution]

Lead selection

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Leadselection is the property which is used to get the index of the selected row of the table

"OnLeadSelect" is the method used to fire an action when a row is selected

The Method wdContext.<node>().getLeadSelection() can be used to

find out the index of the selected element.

Cardinality

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Any node or attribute that has the context root node as its immediate parent, is known as an independent node or attribute.

Any node or attribute that has some other node as its immediate parent, is known as a dependent node or attribute.

All context nodes are collections.

A node collection is composed of elements, where an element is an aggregation of the node’s immediate children (attributes and/or other nodes).

The cardinality property controls the number of elements a node collection may hold at runtime.

Every context node has a property called Cardinality. This property is composed of two values that

taken together, describe the maximum and minimum number of elements the node collection may hold

at runtime.

&#56256;&#56441; Cardinality Minimum: 0 or 1

&#56256;&#56441; Cardinality Maximum: 1 or n

Therefore, there are four possible cardinality values (specified as <Min>..<Max>)

&#56256;&#56441; 0..1 Zero or one elements permitted

&#56256;&#56441; 0..n Zero or more elements permitted

&#56256;&#56441; 1..1 One and only one element permitted

&#56256;&#56441; 1..n One or more elements permitted

Singleton

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All independent nodes are forced to be singletons. This is because the context root node has one and only one element.

Singleton is boolean

TRUE : One instance will be created for all te nodes

FALSE : Every Element in the parent node collection,there will be a distinct instance of the child node.

Why Singleton

-Efficiency

-Less Memory

-Lazy Data Access(Creates instance only when needed,till then it will remain unprocessed)

Regards

Chaitanya.A

[Former Member]

Thank you Chaitanya

Ravi