Java tutorial
/* * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 which accompanies this distribution, * and is available at http://www.eclipse.org/legal/epl-v10.html */ package org.opendaylight.controller.sample.toaster.provider; import static org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType.CONFIGURATION; import static org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType.OPERATIONAL; import static org.opendaylight.yangtools.yang.common.RpcError.ErrorType.APPLICATION; import static org.opendaylight.controller.md.sal.binding.api.DataObjectModification.ModificationType.DELETE; import static org.opendaylight.controller.md.sal.binding.api.DataObjectModification.ModificationType.WRITE; import com.google.common.base.Function; import com.google.common.base.Optional; import com.google.common.util.concurrent.AsyncFunction; import com.google.common.util.concurrent.FutureCallback; import com.google.common.util.concurrent.Futures; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.SettableFuture; import java.util.Collection; import java.util.concurrent.Callable; import java.util.concurrent.ExecutionException; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.Future; import java.util.concurrent.atomic.AtomicLong; import java.util.concurrent.atomic.AtomicReference; import org.opendaylight.controller.md.sal.binding.api.DataBroker; import org.opendaylight.controller.md.sal.binding.api.DataObjectModification; import org.opendaylight.controller.md.sal.binding.api.DataTreeChangeListener; import org.opendaylight.controller.md.sal.binding.api.DataTreeIdentifier; import org.opendaylight.controller.md.sal.binding.api.DataTreeModification; import org.opendaylight.controller.md.sal.binding.api.NotificationPublishService; import org.opendaylight.controller.md.sal.binding.api.ReadWriteTransaction; import org.opendaylight.controller.md.sal.binding.api.WriteTransaction; import org.opendaylight.controller.md.sal.common.api.data.OptimisticLockFailedException; import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException; import org.opendaylight.controller.md.sal.common.util.jmx.AbstractMXBean; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.DisplayString; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.MakeToastInput; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.RestockToasterInput; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.Toaster; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.Toaster.ToasterStatus; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.ToasterBuilder; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.ToasterOutOfBreadBuilder; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.ToasterRestocked; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.ToasterRestockedBuilder; import org.opendaylight.yang.gen.v1.http.netconfcentral.org.ns.toaster.rev091120.ToasterService; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.toaster.app.config.rev160503.ToasterAppConfig; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.controller.toaster.app.config.rev160503.ToasterAppConfigBuilder; import org.opendaylight.yangtools.concepts.ListenerRegistration; import org.opendaylight.yangtools.yang.binding.InstanceIdentifier; import org.opendaylight.yangtools.yang.common.RpcError; import org.opendaylight.yangtools.yang.common.RpcError.ErrorType; import org.opendaylight.yangtools.yang.common.RpcResult; import org.opendaylight.yangtools.yang.common.RpcResultBuilder; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class OpendaylightToaster extends AbstractMXBean implements ToasterService, ToasterProviderRuntimeMXBean, DataTreeChangeListener<Toaster>, AutoCloseable { private static final Logger LOG = LoggerFactory.getLogger(OpendaylightToaster.class); private static final InstanceIdentifier<Toaster> TOASTER_IID = InstanceIdentifier.builder(Toaster.class) .build(); private static final DisplayString TOASTER_MANUFACTURER = new DisplayString("Opendaylight"); private static final DisplayString TOASTER_MODEL_NUMBER = new DisplayString("Model 1 - Binding Aware"); private DataBroker dataProvider; private NotificationPublishService notificationProvider; private ListenerRegistration<OpendaylightToaster> dataTreeChangeListenerRegistration; private final ExecutorService executor; // This holds the Future for the current make toast task and is used to cancel the current toast. private final AtomicReference<Future<?>> currentMakeToastTask = new AtomicReference<>(); // Thread safe holders private final AtomicLong amountOfBreadInStock = new AtomicLong(100); private final AtomicLong toastsMade = new AtomicLong(0); private final AtomicLong darknessFactor = new AtomicLong(1000); private final ToasterAppConfig toasterAppConfig; public OpendaylightToaster() { this(new ToasterAppConfigBuilder().setManufacturer(TOASTER_MANUFACTURER) .setModelNumber(TOASTER_MODEL_NUMBER).setMaxMakeToastTries(2).build()); } public OpendaylightToaster(ToasterAppConfig toasterAppConfig) { super("OpendaylightToaster", "toaster-provider", null); executor = Executors.newFixedThreadPool(1); this.toasterAppConfig = toasterAppConfig; } public void setNotificationProvider(final NotificationPublishService notificationPublishService) { this.notificationProvider = notificationPublishService; } public void setDataProvider(final DataBroker salDataProvider) { this.dataProvider = salDataProvider; dataProvider.registerDataTreeChangeListener(new DataTreeIdentifier<>(CONFIGURATION, TOASTER_IID), this); setToasterStatusUp(null); } /** * Implemented from the AutoCloseable interface. */ @Override public void close() throws ExecutionException, InterruptedException { // When we close this service we need to shutdown our executor! executor.shutdown(); if (dataProvider != null) { dataTreeChangeListenerRegistration.close(); WriteTransaction tx = dataProvider.newWriteOnlyTransaction(); tx.delete(OPERATIONAL, TOASTER_IID); Futures.addCallback(tx.submit(), new FutureCallback<Void>() { @Override public void onSuccess(final Void result) { LOG.debug("Delete Toaster commit result: " + result); } @Override public void onFailure(final Throwable t) { LOG.error("Delete of Toaster failed", t); } }); } } private Toaster buildToaster(final ToasterStatus status) { // note - we are simulating a device whose manufacture and model are // fixed (embedded) into the hardware. // This is why the manufacture and model number are hardcoded. return new ToasterBuilder().setToasterManufacturer(toasterAppConfig.getManufacturer()) .setToasterModelNumber(toasterAppConfig.getModelNumber()).setToasterStatus(status).build(); } /** * Implemented from the DataTreeChangeListener interface. */ @Override public void onDataTreeChanged(Collection<DataTreeModification<Toaster>> changes) { for (DataTreeModification<Toaster> change : changes) { DataObjectModification<Toaster> rootNode = change.getRootNode(); if (rootNode.getModificationType() == WRITE) { Toaster oldToaster = rootNode.getDataBefore(); Toaster newToaster = rootNode.getDataAfter(); LOG.info( "onDataTreeChanged - Toaster config with path {} was added or replaced: old Toaster: {}, new Toaster: {}", change.getRootPath().getRootIdentifier(), oldToaster, newToaster); Long darkness = newToaster.getDarknessFactor(); if (darkness != null) { darknessFactor.set(darkness); } } else if (rootNode.getModificationType() == DELETE) { LOG.info("onDataTreeChanged - Toaster config with path {} was deleted: old Toaster: {}", change.getRootPath().getRootIdentifier(), rootNode.getDataBefore()); } } } /** * RPC call implemented from the ToasterService interface that cancels the current toast, if any. */ @Override public Future<RpcResult<Void>> cancelToast() { Future<?> current = currentMakeToastTask.getAndSet(null); if (current != null) { current.cancel(true); } // Always return success from the cancel toast call return Futures.immediateFuture(RpcResultBuilder.<Void>success().build()); } /** * RPC call implemented from the ToasterService interface that attempts to make toast. */ @Override public Future<RpcResult<Void>> makeToast(final MakeToastInput input) { LOG.info("makeToast: " + input); final SettableFuture<RpcResult<Void>> futureResult = SettableFuture.create(); checkStatusAndMakeToast(input, futureResult, toasterAppConfig.getMaxMakeToastTries()); return futureResult; } private RpcError makeToasterOutOfBreadError() { return RpcResultBuilder.newError(APPLICATION, "resource-denied", "Toaster is out of bread", "out-of-stock", null, null); } private RpcError makeToasterInUseError() { return RpcResultBuilder.newWarning(APPLICATION, "in-use", "Toaster is busy", null, null, null); } private void checkStatusAndMakeToast(final MakeToastInput input, final SettableFuture<RpcResult<Void>> futureResult, final int tries) { // Read the ToasterStatus and, if currently Up, try to write the status to Down. // If that succeeds, then we essentially have an exclusive lock and can proceed // to make toast. final ReadWriteTransaction tx = dataProvider.newReadWriteTransaction(); ListenableFuture<Optional<Toaster>> readFuture = tx.read(OPERATIONAL, TOASTER_IID); final ListenableFuture<Void> commitFuture = Futures.transform(readFuture, (AsyncFunction<Optional<Toaster>, Void>) toasterData -> { ToasterStatus toasterStatus = ToasterStatus.Up; if (toasterData.isPresent()) { toasterStatus = toasterData.get().getToasterStatus(); } LOG.debug("Read toaster status: {}", toasterStatus); if (toasterStatus == ToasterStatus.Up) { if (outOfBread()) { LOG.debug("Toaster is out of bread"); return Futures.immediateFailedCheckedFuture( new TransactionCommitFailedException("", makeToasterOutOfBreadError())); } LOG.debug("Setting Toaster status to Down"); // We're not currently making toast - try to update the status to Down // to indicate we're going to make toast. This acts as a lock to prevent // concurrent toasting. tx.put(OPERATIONAL, TOASTER_IID, buildToaster(ToasterStatus.Down)); return tx.submit(); } LOG.debug("Oops - already making toast!"); // Return an error since we are already making toast. This will get // propagated to the commitFuture below which will interpret the null // TransactionStatus in the RpcResult as an error condition. return Futures.immediateFailedCheckedFuture( new TransactionCommitFailedException("", makeToasterInUseError())); }); Futures.addCallback(commitFuture, new FutureCallback<Void>() { @Override public void onSuccess(final Void result) { // OK to make toast currentMakeToastTask.set(executor.submit(new MakeToastTask(input, futureResult))); } @Override public void onFailure(final Throwable ex) { if (ex instanceof OptimisticLockFailedException) { // Another thread is likely trying to make toast simultaneously and updated the // status before us. Try reading the status again - if another make toast is // now in progress, we should get ToasterStatus.Down and fail. if ((tries - 1) > 0) { LOG.debug("Got OptimisticLockFailedException - trying again"); checkStatusAndMakeToast(input, futureResult, tries - 1); } else { futureResult.set(RpcResultBuilder.<Void>failed() .withError(ErrorType.APPLICATION, ex.getMessage()).build()); } } else { LOG.debug("Failed to commit Toaster status", ex); // Probably already making toast. futureResult.set(RpcResultBuilder.<Void>failed() .withRpcErrors(((TransactionCommitFailedException) ex).getErrorList()).build()); } } }); } /** * RestConf RPC call implemented from the ToasterService interface. * Restocks the bread for the toaster, resets the toastsMade counter to 0, and sends a * ToasterRestocked notification. */ @Override public Future<RpcResult<java.lang.Void>> restockToaster(final RestockToasterInput input) { LOG.info("restockToaster: " + input); amountOfBreadInStock.set(input.getAmountOfBreadToStock()); if (amountOfBreadInStock.get() > 0) { ToasterRestocked reStockedNotification = new ToasterRestockedBuilder() .setAmountOfBread(input.getAmountOfBreadToStock()).build(); notificationProvider.offerNotification(reStockedNotification); } return Futures.immediateFuture(RpcResultBuilder.<Void>success().build()); } /** * JMX RPC call implemented from the ToasterProviderRuntimeMXBean interface. */ @Override public void clearToastsMade() { LOG.info("clearToastsMade"); toastsMade.set(0); } /** * Accesssor method implemented from the ToasterProviderRuntimeMXBean interface. */ @Override public Long getToastsMade() { return toastsMade.get(); } private void setToasterStatusUp(final Function<Boolean, Void> resultCallback) { WriteTransaction tx = dataProvider.newWriteOnlyTransaction(); tx.put(OPERATIONAL, TOASTER_IID, buildToaster(ToasterStatus.Up)); Futures.addCallback(tx.submit(), new FutureCallback<Void>() { @Override public void onSuccess(final Void result) { notifyCallback(true); } @Override public void onFailure(final Throwable t) { // We shouldn't get an OptimisticLockFailedException (or any ex) as no // other component should be updating the operational state. LOG.error("Failed to update toaster status", t); notifyCallback(false); } void notifyCallback(final boolean result) { if (resultCallback != null) { resultCallback.apply(result); } } }); } private boolean outOfBread() { return amountOfBreadInStock.get() == 0; } private class MakeToastTask implements Callable<Void> { final MakeToastInput toastRequest; final SettableFuture<RpcResult<Void>> futureResult; public MakeToastTask(final MakeToastInput toastRequest, final SettableFuture<RpcResult<Void>> futureResult) { this.toastRequest = toastRequest; this.futureResult = futureResult; } @Override public Void call() { try { // make toast just sleeps for n seconds per doneness level. long darknessFactor = OpendaylightToaster.this.darknessFactor.get(); Thread.sleep(darknessFactor * toastRequest.getToasterDoneness()); } catch (InterruptedException e) { LOG.info("Interrupted while making the toast"); } toastsMade.incrementAndGet(); amountOfBreadInStock.getAndDecrement(); if (outOfBread()) { LOG.info("Toaster is out of bread!"); notificationProvider.offerNotification(new ToasterOutOfBreadBuilder().build()); } // Set the Toaster status back to up - this essentially releases the toasting lock. // We can't clear the current toast task nor set the Future result until the // update has been committed so we pass a callback to be notified on completion. setToasterStatusUp(result -> { currentMakeToastTask.set(null); LOG.debug("Toast done"); futureResult.set(RpcResultBuilder.<Void>success().build()); return null; }); return null; } } }