How to use ThreadPoolExecutor / ArrayBlockingQueue with event objects

Question

I am having some trouble figuring out how to use the new java.util.concurrent library for a simple thread pool that has custom threads pulling off event objects from a queue.
I started with this kind of code below, which I know is not right but am having trouble seeing the correct approach. Any help is appreciated. Thank You!
-Paul
public class testThreadPool {
public static void main( String [] args ) {
//work queue actaully only takes runnables,
//but I need to add my event objects to this queue ??
ArrayBlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<Runnable>(20);
ThreadPoolExecutor pool = new ThreadPoolExecutor(10,//pool size
20,//max pool size
1,
TimeUnit.SECONDS,
workQueue);//the work queue
//this will ensure that the pool executor creates worker
//threads of type MyThreadWorker
pool.setThreadFactory(new MyThreadFactory());
pool.prestartAllCoreThreads();
//throw some events on the queue and let the pool workers
//start to execute with the given event object
workQueue.add(MyEvent);
workQueue.add(AnotherEvent);
class MyThreadFactory implements ThreadFactory {
public Thread newThread(Runnable runnable) {
return new (Thread)MyThreadWorker();
class MyThreadWorker implements Runnable {
private boolean m_run = true;
public void run(){
Object obj;
while (m_run) {
obj = null;
//get the event object from the blocking queue
try {
obj = workQueue.take();
} catch (InterruptedException e) {
if ( obj == null ) continue;
if ( obj == null ) continue;
if (obj instanceof MyEvent) {
//do this
} else if (obj instanceof AnotherEvent) {
//do this
public void stopRunning(){
m_run = false;
this.interrupt();
}

Answer 1

What database and connection type are you using? Are you connecting the report directly to the database, or trying to assign the datasource to object data?
It sounds like you might be trying to use a linked list, collection or other C# construct to pass your data in. This currently isn't supported by the Crystal Reports SDK. You can use a DataSet or a DataTable, and possibly also an IDataReader depending on which version of Crystal Reports you're referencing in your project. Of course you can also connect directly to the database, even if the database isn't on the same machine as the application.
The way to show master records with detail information is through the use of subreports and linked subreport parameters. Linked subreports take their parameter value from a record in the main report, so that only the data appropriate to that master record is displayed. The guys over in the [report design|SAP Crystal Reports; forum can help you out with this if you have questions on the specifics.