I did something like this using a global static boolean variable
(flag) while I was implementing breadth first IDA*. In my case, I set
the flag to something else if a solution was found, which was examined
in the reducer.
I guess in your case, since you know that if the mappers don't produce
anything the reducers won't have anything as input, if I am not wrong.
And I had chaining map-reduce jobs ( http://developer.yahoo.com/hadoop/tutorial/module4.html
) running until a solution was found.
Kind regards,
Arindam Khaled
On Dec 17, 2010, at 12:58 AM, Peng, Wei wrote:
Hi,
I am a newbie of hadoop.
Today I was struggling with a hadoop problem for several hours.
I initialize a parameter by setting job configuration in main.
E.g. Configuration con = new Configuration();
con.set("test", "1");
Job job = new Job(con);
Then in the mapper class, I want to set "test" to "2". I did it by
context.getConfiguration().set("test","2");
Finally in the main method, after the job is finished, I check the
"test" again by
job.getConfiguration().get("test");
However, the value of "test" is still "1".
The reason why I want to change the parameter inside Mapper class is
that I want to determine when to stop an iteration in the main method.
For example, for doing breadth-first search, when there is no new
nodes
are added for further expansion, the searching iteration should stop.
Your help will be deeply appreciated. Thank you
Wei
