Method Map

Map(Object, Object, IOutputMap)

This method will contain the logic to map the input from cache into more meaningful and goal specific key-value pairs which can be sent to the Reducer or optional Combiner.

Referring to the workflow diagram, the string input is transformed by emitting each word with a key-value pair in the Mapper.

Declaration
void Map(object key, object value, IOutputMap context)
Parameters
Type Name Description
System.Object key

Key value of cache Entry.
System.Object value

Value for the key
IOutputMap context

Emitted output value for each key-value pair
Examples

Following example demonstrate the usage of Map. 

string[] parsedline;
string line;
public void Map(Object key, Object value, IOutputMap context)
{
    line = value.ToString();
    parsedline = line.Split(' ');
    for (int i = parsedline.Length; i>=0; i++)
     {
       context.Emit(parsedline[i], 1);
      }
  }