Java tutorial
/* * Copyright (c) 2013 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.bgpcep.programming.impl; import com.google.common.base.Preconditions; 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.ListeningExecutorService; import com.google.common.util.concurrent.SettableFuture; import io.netty.util.Timeout; import io.netty.util.Timer; import io.netty.util.TimerTask; import java.math.BigInteger; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.concurrent.Callable; import java.util.concurrent.TimeUnit; import org.opendaylight.bgpcep.programming.NanotimeUtil; import org.opendaylight.bgpcep.programming.spi.ExecutionResult; import org.opendaylight.bgpcep.programming.spi.Instruction; import org.opendaylight.bgpcep.programming.spi.InstructionScheduler; import org.opendaylight.bgpcep.programming.spi.SchedulerException; import org.opendaylight.bgpcep.programming.spi.SuccessfulRpcResult; import org.opendaylight.controller.md.sal.binding.api.DataBroker; import org.opendaylight.controller.md.sal.binding.api.WriteTransaction; import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType; import org.opendaylight.controller.sal.binding.api.NotificationProviderService; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CancelInstructionInput; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CancelInstructionOutput; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CancelInstructionOutputBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CleanInstructionsInput; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CleanInstructionsOutput; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.CleanInstructionsOutputBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.DeadOnArrival; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.DuplicateInstructionId; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionId; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionStatus; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionStatusChangedBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionsQueue; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionsQueueBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.InstructionsQueueKey; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.Nanotime; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.ProgrammingService; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.SubmitInstructionInput; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.UnknownInstruction; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.UnknownPreconditionId; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.queue.InstructionBuilder; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.queue.InstructionKey; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.status.changed.Details; import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.submit.instruction.output.result.failure._case.FailureBuilder; import org.opendaylight.yangtools.yang.binding.InstanceIdentifier; import org.opendaylight.yangtools.yang.binding.KeyedInstanceIdentifier; import org.opendaylight.yangtools.yang.common.RpcResult; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public final class ProgrammingServiceImpl implements AutoCloseable, InstructionScheduler, ProgrammingService { private static final Logger LOG = LoggerFactory.getLogger(ProgrammingServiceImpl.class); private final Map<InstructionId, InstructionImpl> insns = new HashMap<>(); private final InstanceIdentifier<InstructionsQueue> qid; private final NotificationProviderService notifs; private final ListeningExecutorService executor; private final DataBroker dataProvider; private final Timer timer; private final class InstructionPusher implements QueueInstruction { private final InstructionBuilder builder = new InstructionBuilder(); InstructionPusher(final InstructionId id, final Nanotime deadline) { this.builder.setDeadline(deadline); this.builder.setId(id); this.builder.setKey(new InstructionKey(id)); this.builder.setStatus(InstructionStatus.Queued); } @Override public void instructionUpdated(final InstructionStatus status, final Details details) { if (!status.equals(this.builder.getStatus())) { this.builder.setStatus(status); final WriteTransaction t = ProgrammingServiceImpl.this.dataProvider.newWriteOnlyTransaction(); t.put(LogicalDatastoreType.OPERATIONAL, ProgrammingServiceImpl.this.qid.child( org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.queue.Instruction.class, new InstructionKey(this.builder.getId())), this.builder.build()); t.submit(); } ProgrammingServiceImpl.this.notifs.publish(new InstructionStatusChangedBuilder() .setId(this.builder.getId()).setStatus(status).setDetails(details).build()); } @Override public void instructionRemoved() { final WriteTransaction t = ProgrammingServiceImpl.this.dataProvider.newWriteOnlyTransaction(); t.delete(LogicalDatastoreType.OPERATIONAL, ProgrammingServiceImpl.this.qid.child( org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.queue.Instruction.class, new InstructionKey(this.builder.getId()))); t.submit(); } } public ProgrammingServiceImpl(final DataBroker dataProvider, final NotificationProviderService notifs, final ListeningExecutorService executor, final Timer timer, final InstructionsQueueKey instructionsQueueKey) { this.dataProvider = Preconditions.checkNotNull(dataProvider); this.notifs = Preconditions.checkNotNull(notifs); this.executor = Preconditions.checkNotNull(executor); this.timer = Preconditions.checkNotNull(timer); this.qid = KeyedInstanceIdentifier.builder(InstructionsQueue.class, instructionsQueueKey).build(); final WriteTransaction t = dataProvider.newWriteOnlyTransaction(); t.put(LogicalDatastoreType.OPERATIONAL, this.qid, new InstructionsQueueBuilder().setKey(instructionsQueueKey).setInstruction( Collections.<org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.programming.rev150720.instruction.queue.Instruction>emptyList()) .build()); t.submit(); } @Override public ListenableFuture<RpcResult<CancelInstructionOutput>> cancelInstruction( final CancelInstructionInput input) { return this.executor.submit(new Callable<RpcResult<CancelInstructionOutput>>() { @Override public RpcResult<CancelInstructionOutput> call() { return realCancelInstruction(input); } }); } @Override public ListenableFuture<RpcResult<CleanInstructionsOutput>> cleanInstructions( final CleanInstructionsInput input) { return this.executor.submit(new Callable<RpcResult<CleanInstructionsOutput>>() { @Override public RpcResult<CleanInstructionsOutput> call() { return realCleanInstructions(input); } }); } private synchronized RpcResult<CancelInstructionOutput> realCancelInstruction( final CancelInstructionInput input) { final InstructionImpl i = this.insns.get(input.getId()); if (i == null) { LOG.debug("Instruction {} not present in the graph", input.getId()); final CancelInstructionOutput out = new CancelInstructionOutputBuilder() .setFailure(UnknownInstruction.class).build(); return SuccessfulRpcResult.create(out); } return SuccessfulRpcResult .create(new CancelInstructionOutputBuilder().setFailure(i.tryCancel(null)).build()); } private synchronized RpcResult<CleanInstructionsOutput> realCleanInstructions( final CleanInstructionsInput input) { final List<InstructionId> failed = new ArrayList<>(); for (final InstructionId id : input.getId()) { // Find the instruction final InstructionImpl i = this.insns.get(id); if (i == null) { LOG.debug("Instruction {} not present in the graph", input.getId()); failed.add(id); continue; } // Check its status switch (i.getStatus()) { case Cancelled: case Failed: case Successful: break; case Executing: case Queued: case Scheduled: case Unknown: LOG.debug("Instruction {} cannot be cleaned because of it's in state {}", id, i.getStatus()); failed.add(id); continue; default: break; } // The instruction is in a terminal state, we need to just unlink // it from its dependencies and dependents i.clean(); this.insns.remove(id); LOG.debug("Instruction {} cleaned successfully", id); } final CleanInstructionsOutputBuilder ob = new CleanInstructionsOutputBuilder(); ob.setUnflushed(failed); return SuccessfulRpcResult.create(ob.build()); } private List<InstructionImpl> checkDependencies(final SubmitInstructionInput input) throws SchedulerException { final List<InstructionImpl> dependencies = collectDependencies(input); // Check if all dependencies are non-failed final List<InstructionId> unmet = checkIfUnfailed(dependencies); /* * Some dependencies have failed, declare the request dead-on-arrival * and fail the operation. */ if (!unmet.isEmpty()) { throw new SchedulerException("Instruction's dependencies are already unsuccessful", new FailureBuilder().setType(DeadOnArrival.class).setFailedPreconditions(unmet).build()); } return dependencies; } private List<InstructionImpl> collectDependencies(final SubmitInstructionInput input) throws SchedulerException { final List<InstructionImpl> dependencies = new ArrayList<>(); for (final InstructionId pid : input.getPreconditions()) { final InstructionImpl i = this.insns.get(pid); if (i == null) { LOG.info("Instruction {} depends on {}, which is not a known instruction", input.getId(), pid); throw new SchedulerException("Unknown dependency ID specified", new FailureBuilder().setType(UnknownPreconditionId.class).build()); } dependencies.add(i); } return dependencies; } private List<InstructionId> checkIfUnfailed(final List<InstructionImpl> dependencies) { final List<InstructionId> unmet = new ArrayList<>(); for (final InstructionImpl d : dependencies) { switch (d.getStatus()) { case Cancelled: case Failed: case Unknown: unmet.add(d.getId()); break; case Executing: case Queued: case Scheduled: case Successful: break; default: break; } } return unmet; } @Override public synchronized ListenableFuture<Instruction> scheduleInstruction(final SubmitInstructionInput input) throws SchedulerException { final InstructionId id = input.getId(); if (this.insns.get(id) != null) { LOG.info("Instruction ID {} already present", id); throw new SchedulerException("Instruction ID currently in use", new FailureBuilder().setType(DuplicateInstructionId.class).build()); } // First things first: check the deadline final Nanotime now = NanotimeUtil.currentTime(); final BigInteger left = input.getDeadline().getValue().subtract(now.getValue()); if (left.compareTo(BigInteger.ZERO) <= 0) { LOG.debug("Instruction {} deadline has already passed by {}ns", id, left); throw new SchedulerException("Instruction arrived after specified deadline", new FailureBuilder().setType(DeadOnArrival.class).build()); } // Resolve dependencies final List<InstructionImpl> dependencies = checkDependencies(input); /* * All pre-flight checks done are at this point, the following * steps can only fail in catastrophic scenarios (OOM and the * like). */ // Schedule a timeout for the instruction final Timeout t = this.timer.newTimeout(new TimerTask() { @Override public void run(final Timeout timeout) { timeoutInstruction(input.getId()); } }, left.longValue(), TimeUnit.NANOSECONDS); // Put it into the instruction list final SettableFuture<Instruction> ret = SettableFuture.create(); final InstructionImpl i = new InstructionImpl(new InstructionPusher(id, input.getDeadline()), ret, id, dependencies, t); this.insns.put(id, i); // Attach it into its dependencies for (final InstructionImpl d : dependencies) { d.addDependant(i); } /* * All done. The next part is checking whether the instruction can * run, which we can figure out after sending out the acknowledgement. * This task should be ingress-weighed, so we reinsert it into the * same execution service. */ this.executor.submit(new Runnable() { @Override public void run() { tryScheduleInstruction(i); } }); return ret; } private synchronized void timeoutInstruction(final InstructionId id) { final InstructionImpl i = this.insns.get(id); if (i == null) { LOG.warn("Instruction {} timed out, but not found in the queue", id); return; } i.timeout(); } private synchronized void tryScheduleDependants(final InstructionImpl i) { // Walk all dependants and try to schedule them final Iterator<InstructionImpl> it = i.getDependants(); while (it.hasNext()) { tryScheduleInstruction(it.next()); } } private synchronized void tryScheduleInstruction(final InstructionImpl i) { final ListenableFuture<ExecutionResult<Details>> f = i.ready(); if (f != null) { Futures.addCallback(f, new FutureCallback<ExecutionResult<Details>>() { @Override public void onSuccess(final ExecutionResult<Details> result) { tryScheduleDependants(i); } @Override public void onFailure(final Throwable t) { LOG.error("Instruction {} failed to execute", i.getId(), t); } }); } } @Override public synchronized void close() { try { for (final InstructionImpl i : this.insns.values()) { i.tryCancel(null); } // Workaround for BUG-2283 final WriteTransaction t = this.dataProvider.newWriteOnlyTransaction(); t.delete(LogicalDatastoreType.OPERATIONAL, this.qid); t.submit().checkedGet(); } catch (final Exception e) { LOG.error("Failed to shutdown Instruction Queue", e); } } }