Examples with CopyOnReadTupleSource org.teiid.dqp.internal.process.TupleSourceCache.CopyOnReadTupleSource used on opensource projects

Example 1 with CopyOnReadTupleSource

use of org.teiid.dqp.internal.process.TupleSourceCache.CopyOnReadTupleSource in project teiid by teiid.

the class DataTierManagerImpl method handleThreadBound.

/**
 * thread bound work is tricky for our execution model
 *
 * the strategy here is that
 *
 * - if the result is not already a copying tuplesource (from caching)
 * then wrap in a copying tuple source
 *
 * - submit a workitem that will pull the results/fill the buffer,
 *
 * - return a tuplesource off of the buffer for use by the caller
 */
private TupleSource handleThreadBound(final RequestWorkItem workItem, AtomicRequestMessage aqr, ConnectorWork work, CacheID cid, TupleSource result, DataTierTupleSource dtts, TupleBuffer tb) throws AssertionError, TeiidComponentException, TeiidProcessingException {
    if (workItem.useCallingThread) {
        // in any case we want the underlying work done in the thread accessing the connectorworkitem
        aqr.setSerial(true);
        // simple case, just rely on the client using the same thread
        return result;
    }
    if (tb == null) {
        tb = getBufferManager().createTupleBuffer(aqr.getCommand().getProjectedSymbols(), aqr.getCommandContext().getConnectionId(), TupleSourceType.PROCESSOR);
    }
    final TupleSource ts = tb.createIndexedTupleSource(cid == null);
    if (cid == null) {
        result = new CopyOnReadTupleSource(tb, result) {

            @Override
            public void closeSource() {
                ts.closeSource();
            }
        };
    }
    final ThreadBoundTask callable = new ThreadBoundTask(workItem, result, dtts);
    // but we do so lazily just in case the results aren't needed
    if (aqr.isSerial()) {
        return new TupleSource() {

            boolean processed = false;

            @Override
            public List<?> nextTuple() throws TeiidComponentException, TeiidProcessingException {
                if (!processed) {
                    callable.call();
                    callable.onCompletion(null);
                    processed = true;
                }
                return ts.nextTuple();
            }

            @Override
            public void closeSource() {
                if (!processed) {
                    callable.onCompletion(null);
                    processed = true;
                }
                ts.closeSource();
            }
        };
    }
    aqr.setSerial(true);
    final FutureWork<Void> future = workItem.addWork(callable, callable, 100);
    final TupleBuffer buffer = tb;
    // return a thread-safe TupleSource
    return new TupleSource() {

        boolean checkedDone;

        @Override
        public List<?> nextTuple() throws TeiidComponentException, TeiidProcessingException {
            // TODO: could refactor as completion listener
            if (!checkedDone && future.isDone()) {
                checkedDone = true;
                try {
                    future.get();
                } catch (InterruptedException e) {
                    throw new TeiidComponentException(e);
                } catch (ExecutionException e) {
                    if (e.getCause() instanceof TeiidComponentException) {
                        throw (TeiidComponentException) e.getCause();
                    }
                    if (e.getCause() instanceof TeiidProcessingException) {
                        throw (TeiidProcessingException) e.getCause();
                    }
                    throw new TeiidComponentException(e);
                }
            }
            synchronized (buffer) {
                return ts.nextTuple();
            }
        }

        @Override
        public void closeSource() {
            synchronized (buffer) {
                ts.closeSource();
            }
            callable.done.set(true);
        }
    };
}