org.apache.geode.cache.execute

Interface ResultSender<T>

public interface ResultSender<T>

Provides methods to send results back to the ResultCollector. A ResultSender adds the ability for an execute method to send a single result back, or break its result into multiple pieces and send each piece back to the calling thread's ResultCollector. For each result sent using this method, ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object) is called, making that result available to the calling thread immediately.

Example:

      execute(FunctionContext context){
              ResultSender rs = context.getResultSender();
              int lastResult = -1;
              for(int i=0;i< 10; i++) {
                      rs.sendResult(i);
              }
              rs.lastResult(lastResult);
      }

  Application can receive the results as they are sent using ResultSender in the above for loop.
  It is very important to send a last result as it informs ResultCollector
  to stop waiting for the result.
 

 

Since:

GemFire 6.0

See Also:

ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object)

Method Summary

Modifier and Type	Method and Description
void	lastResult(T lastResult) Sends a result back to the FunctionService calling thread and invokes ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object) and then ResultCollector.endResults() if it is the last instance of the Function to report results.
void	sendException(Throwable t) Sends an Exception back to the FunctionService calling thread.
void	sendResult(T oneResult) Sends a result back to the FunctionService calling thread and invokes ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object).

Method Detail

sendResult

void sendResult(T oneResult)

Sends a result back to the FunctionService calling thread and invokes ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object).

Parameters:

oneResult - the result to be sent

lastResult

void lastResult(T lastResult)

Sends a result back to the FunctionService calling thread and invokes ResultCollector.addResult(org.apache.geode.distributed.DistributedMember, Object) and then ResultCollector.endResults() if it is the last instance of the Function to report results. The ResultCollector will keep waiting for results until it receives last result. Therefore, it is very important to use this method to indicate end of function execution.

Parameters:

lastResult - the result to be sent

Throws:

IllegalStateException - if called more than once

See Also:

ResultCollector.endResults()

sendException

void sendException(Throwable t)

Sends an Exception back to the FunctionService calling thread. sendException adds exception to ResultCollector as a result. If sendException is called then ResultCollector.getResult() will not throw exception but will have exception as a part of results received. Calling sendException will act as a lastResult.

Parameters:

t - the Throwable to be sent

Since:

GemFire 6.3

See Also:

lastResult(Object)