LATEST VERSION: 8.2.6 - CHANGELOG
Pivotal GemFire® v8.2

Running the Continuous Query Code

Running the Continuous Query Code

Create your CQ from an instance of the QueryService . Once created, the CQ is maintained primarily through the CqQuery interface. The following two C++ and C# examples show the basic calls in the CQ life cycle.

CQ Creation, Execution, and Close (C++)

// Get cache and qrySvcPtr - refs to local cache and QueryService
// Create client /tradeOrder region configured to talk to the server
// Create CqAttribute using CqAttributeFactory
CqAttributesFactory cqf;
// Create a listener and add it to the CQ attributes
// callback defined below
CqListenerPtr tradeEventListener (new TradeEventListener());
QueryServicePtr qrySvcPtr = cachePtr->getQueryService();" cqf.addCqListener(tradeEventListener);
CqAttributesPtr cqa = cqf.create();
// Name of the CQ and its query
char* cqName = "priceTracker";
char* queryStr = "SELECT * FROM /tradeOrder t where t.price > 100.00";
// Create the CqQuery
CqQueryPtr priceTracker = qrySvcPtr->newCq(cqName, queryStr, cqa); try {
  // Execute CQ
  priceTracker->execute();
} catch (Exception& ex){
  ex.printStackTrace();
}
  // Now the CQ is running on the server, sending CqEvents to the listener
  . . .
}
// End of life for the CQ - clear up resources by closing
priceTracker->close()

CQ Creation, Execution, and Close (C# .NET)

// Get cache and queryService - refs to local cache and QueryService
// Create client /tradeOrder region configured to talk to the server
// Create CqAttribute using CqAttributeFactory
CqAttributesFactory cqf = new CqAttributesFactory();
// Create a listener and add it to the CQ attributes
//callback defined below
ICqListener tradeEventListener = new TradeEventListener();
cqf.addCqListener(tradeEventListener);
CqAttributes cqa = cqf.create();
// Name of the CQ and its query
String cqName = "priceTracker ";
String queryStr = "SELECT * FROM /tradeOrder t where t.price >100.00 ";
QueryService queryService = cache.GetQueryService();
// Create the CqQuery
CqQuery priceTracker = queryService.newCq(cqName, queryStr, cqa, true);
try {
  // Execute CQ
  priceTracker.execute();
  }catch (Exception ex){
  //handle exception
  }
// Now the CQ is running on the server, sending CqEvents to the listener
// . . .
}
// End of life for the CQ - clear up resources by closing
priceTracker.close();