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);
      }
  }