Java tutorial
/* * Copyright (c) 2015 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.toaster; // !!! NOTE: The imports must be in this order, or checkstyle will not pass!!! // In Eclipse, use CONTROL+SHIFT+o or CMD+SHIFT+o (mac) to properly order imports // 3rd party imports 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.concurrent.Callable; 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; // MD-SAL APIs import org.opendaylight.controller.md.sal.binding.api.DataBroker; import org.opendaylight.controller.md.sal.binding.api.DataChangeListener; 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.AsyncDataBroker.DataChangeScope; import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeEvent; import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType; import org.opendaylight.controller.md.sal.common.api.data.OptimisticLockFailedException; import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException; import org.opendaylight.controller.sal.binding.api.BindingAwareBroker.ProviderContext; import org.opendaylight.controller.sal.binding.api.BindingAwareBroker.RpcRegistration; import org.opendaylight.controller.sal.binding.api.BindingAwareProvider; import org.opendaylight.controller.sal.binding.api.NotificationProviderService; // Interfaces generated from the toaster yang model 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.toaster.impl.config.rev141210.ToasterImplRuntimeMXBean; // Yangtools methods to manipulate RPC DTOs import org.opendaylight.yangtools.concepts.ListenerRegistration; import org.opendaylight.yangtools.yang.binding.DataObject; 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 ToasterImpl implements BindingAwareProvider, ToasterService, DataChangeListener, ToasterImplRuntimeMXBean, AutoCloseable { private static final Logger LOG = LoggerFactory.getLogger(ToasterImpl.class); private ProviderContext providerContext; private NotificationProviderService notificationService; private DataBroker dataService; private RpcRegistration<ToasterService> rpcReg; private ListenerRegistration<DataChangeListener> dcReg; public 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 final ExecutorService executor; // The following holds the Future for the current make toast task. // This is used to cancel the current toast. private final AtomicReference<Future<?>> currentMakeToastTask = new AtomicReference<>(); private final AtomicLong amountOfBreadInStock = new AtomicLong(100); private final AtomicLong toastsMade = new AtomicLong(0); // Thread safe holder for our darkness multiplier. private final AtomicLong darknessFactor = new AtomicLong(1000); public ToasterImpl() { executor = Executors.newFixedThreadPool(1); } /************************************************************************** * AutoCloseable Method *************************************************************************/ /** * Called when MD-SAL closes the active session. Cleanup is performed, i.e. * all active registrations with MD-SAL are closed, */ @Override public void close() throws Exception { // When we close this service we need to shutdown our executor! executor.shutdown(); // Delete toaster operational data from the MD-SAL data store WriteTransaction tx = dataService.newWriteOnlyTransaction(); tx.delete(LogicalDatastoreType.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); } }); // Close active registrations rpcReg.close(); dcReg.close(); LOG.info("ToasterImpl: registrations closed"); } /************************************************************************** * BindingAwareProvider Methods *************************************************************************/ @Override public void onSessionInitiated(ProviderContext session) { this.providerContext = session; this.notificationService = session.getSALService(NotificationProviderService.class); this.dataService = session.getSALService(DataBroker.class); // Register the RPC Service rpcReg = session.addRpcImplementation(ToasterService.class, this); // Register the DataChangeListener for Toaster's configuration subtree dcReg = dataService.registerDataChangeListener(LogicalDatastoreType.CONFIGURATION, TOASTER_IID, this, DataChangeScope.SUBTREE); // Initialize operational and default config data in MD-SAL data store initToasterOperational(); initToasterConfiguration(); LOG.info("onSessionInitiated: initialization done"); } /************************************************************************** * ToasterService Methods *************************************************************************/ /** * Restconf RPC call implemented from the ToasterService interface. * Cancels the current toast. * Implementation to be filled in a later chapter. * in postman, http://localhost:8181/restconf/operations/toaster:cancel-toast */ @Override public Future<RpcResult<Void>> cancelToast() { LOG.info("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()); } /** * RestConf RPC call implemented from the ToasterService interface. * Attempts to make toast. * Implementation to be filled in a later chapter. * in postman, http://localhost:8181/restconf/operations/toaster:make-toast * { "input" : { "toaster:toasterDoneness" : "10", "toaster:toasterToastType":"wheat-bread" } } */ @Override public Future<RpcResult<Void>> makeToast(final MakeToastInput input) { LOG.info("makeToast: {}", input); final SettableFuture<RpcResult<Void>> futureResult = SettableFuture.create(); checkStatusAndMakeToast(input, futureResult, 2); LOG.info("makeToast returning..."); return futureResult; } /** * RestConf RPC call implemented from the ToasterService interface. * Restocks the bread for the toaster * Implementation to be filled in a later chapter. * in postman, http://localhost:8181/restconf/operations/toaster:restock-toaster * { "input" : { "toaster:amountOfBreadToStock" : "3" } } */ @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(); notificationService.publish(reStockedNotification); } return Futures.immediateFuture(RpcResultBuilder.<Void>success().build()); } /************************************************************************** * DataChangeListener Methods *************************************************************************/ /** * Receives data change events on toaster's configuration subtree. Invoked * when data is written into the toaster's configuration subtree in the * MD-SAL data store. */ @Override public void onDataChanged(final AsyncDataChangeEvent<InstanceIdentifier<?>, DataObject> change) { DataObject dataObject = change.getUpdatedSubtree(); if (dataObject instanceof Toaster) { Toaster toaster = (Toaster) dataObject; Long darkness = toaster.getDarknessFactor(); if (darkness != null) { darknessFactor.set(darkness); } LOG.info("onDataChanged - new Toaster config: {}", toaster); } } /************************************************************************** * ToasterImpl Private Methods *************************************************************************/ /** * Populates toaster's initial operational data into the MD-SAL operational * data store. * 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 */ private void initToasterOperational() { // Build the initial toaster operational data Toaster toaster = buildToaster(ToasterStatus.Up); // Put the toaster operational data into the MD-SAL data store WriteTransaction tx = dataService.newWriteOnlyTransaction(); tx.put(LogicalDatastoreType.OPERATIONAL, TOASTER_IID, toaster); Futures.addCallback(tx.submit(), new FutureCallback<Void>() { @Override public void onSuccess(final Void result) { LOG.info("initToasterOperational: transaction succeeded"); } @Override public void onFailure(final Throwable t) { LOG.error("initToasterOperational: transaction failed"); } }); LOG.info("initToasterOperational: operational status populated: {}", toaster); } /** * Populates toaster's default config data into the MD-SAL configuration * data store. */ private void initToasterConfiguration() { // Build the default toaster config data Toaster toaster = new ToasterBuilder().setDarknessFactor(darknessFactor.get()).build(); // Place default config data in data store tree WriteTransaction tx = dataService.newWriteOnlyTransaction(); tx.put(LogicalDatastoreType.CONFIGURATION, TOASTER_IID, toaster); Futures.addCallback(tx.submit(), new FutureCallback<Void>() { @Override public void onSuccess(final Void result) { LOG.info("initToasterConfiguration: transaction succeeded"); } @Override public void onFailure(final Throwable t) { LOG.error("initToasterConfiguration: transaction failed"); } }); LOG.info("initToasterConfiguration: default config populated: {}", toaster); } private RpcError makeToasterOutOfBreadError() { return RpcResultBuilder.newError(ErrorType.APPLICATION, "resource-denied", "Toaster is out of bread", "out-of-stock", null, null); } private RpcError makeToasterInUseError() { return RpcResultBuilder.newWarning(ErrorType.APPLICATION, "in-use", "Toaster is busy", null, null, null); } private Toaster buildToaster(final ToasterStatus status) { return new ToasterBuilder().setToasterManufacturer(TOASTER_MANUFACTURER) .setToasterModelNumber(TOASTER_MODEL_NUMBER).setToasterStatus(status).build(); } private void setToasterStatusUp(final Function<Boolean, Void> resultCallback) { WriteTransaction tx = dataService.newWriteOnlyTransaction(); tx.put(LogicalDatastoreType.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; } /** * 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. */ private void checkStatusAndMakeToast(final MakeToastInput input, final SettableFuture<RpcResult<Void>> futureResult, final int tries) { LOG.info("checkStatusAndMakeToast"); final ReadWriteTransaction tx = dataService.newReadWriteTransaction(); ListenableFuture<Optional<Toaster>> readFuture = tx.read(LogicalDatastoreType.OPERATIONAL, TOASTER_IID); final ListenableFuture<Void> commitFuture = Futures.transform(readFuture, new AsyncFunction<Optional<Toaster>, Void>() { @Override public ListenableFuture<Void> apply(final Optional<Toaster> toasterData) throws Exception { 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(LogicalDatastoreType.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()); } } }); } 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 = ToasterImpl.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!"); notificationService.publish(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(new Function<Boolean, Void>() { @Override public Void apply(final Boolean result) { currentMakeToastTask.set(null); LOG.debug("Toast done"); futureResult.set(RpcResultBuilder.<Void>success().build()); return null; } }); return null; } } /** * JMX RPC call implemented from the ToasterImplRuntimeMXBean interface. Use jconcole to attach to karaf * to gain access to clearToastsMade and getToastsMade. jconsole is run from the shell! */ @Override public void clearToastsMade() { LOG.info("clearToastsMade"); toastsMade.set(0); } /** * Accesssor method implemented from the ToasterImplRuntimeMXBean interface. */ @Override public Long getToastsMade() { return toastsMade.get(); } }