Context APIs 
The following interfaces and a structure in the ABAP Dictionary are provided for the Web Dynpro Context in which the data is stored:
IF_WD_CONTEXT
IF_WD_CONTEXT_NODE
IF_WD_CONTEXT_NODE_INFO
IF_WD_CONTEXT_ELEMENT
Structure WDR_CONTEXT_ATTRIBUTE_INFO:
Structure WDR_CONTEXT_ATTRIBUTE_INFO provides meta information for a Context node attribute.
The most important components are:
NAME
DEFAULT_VALUE
IS_READ_ONLY
TYPE_NAME
NODE_INFO
IF_WD_CONTEXT_NODE_RANGE
The context methods always trigger CX_WD_CONTEXT if there is an error, but this is not declared.
You can find more information about interfaces in the system in the relevant system documentation.