Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.apache.brooklyn.policy.action; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.List; import java.util.Map; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; import java.util.concurrent.atomic.AtomicBoolean; import org.apache.brooklyn.api.effector.Effector; import org.apache.brooklyn.api.entity.EntityLocal; import org.apache.brooklyn.api.sensor.AttributeSensor; import org.apache.brooklyn.api.sensor.SensorEvent; import org.apache.brooklyn.api.sensor.SensorEventListener; import org.apache.brooklyn.config.ConfigKey; import org.apache.brooklyn.core.config.ConfigKeys; import org.apache.brooklyn.core.entity.EntityInitializers; import org.apache.brooklyn.core.entity.trait.Startable; import org.apache.brooklyn.core.policy.AbstractPolicy; import org.apache.brooklyn.util.collections.MutableList; import org.apache.brooklyn.util.core.config.ConfigBag; import org.apache.brooklyn.util.core.config.ResolvingConfigBag; import org.apache.brooklyn.util.core.task.Tasks; import org.apache.brooklyn.util.exceptions.Exceptions; import org.apache.brooklyn.util.exceptions.RuntimeInterruptedException; import org.apache.brooklyn.util.guava.Maybe; import org.apache.brooklyn.util.time.Duration; import org.apache.brooklyn.util.time.DurationPredicates; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.annotations.Beta; import com.google.common.base.Predicates; import com.google.common.collect.ImmutableList; import com.google.common.collect.ImmutableMap; import com.google.common.collect.Iterables; import com.google.common.reflect.TypeToken; @Beta public abstract class AbstractScheduledEffectorPolicy extends AbstractPolicy implements Runnable, SensorEventListener<Object> { private static final Logger LOG = LoggerFactory.getLogger(AbstractScheduledEffectorPolicy.class); public static final String TIME_FORMAT = "HH:mm:ss"; public static final String NOW = "now"; public static final String IMMEDIATELY = "immediately"; private static final DateFormat FORMATTER = SimpleDateFormat.getTimeInstance(); public static final ConfigKey<String> EFFECTOR = ConfigKeys.builder(String.class).name("effector") .description("The effector to be executed by this policy").constraint(Predicates.notNull()).build(); public static final ConfigKey<Map<String, Object>> EFFECTOR_ARGUMENTS = ConfigKeys .builder(new TypeToken<Map<String, Object>>() { }).name("args").description("The effector arguments and their values").constraint(Predicates.notNull()) .defaultValue(ImmutableMap.<String, Object>of()).build(); public static final ConfigKey<String> TIME = ConfigKeys.builder(String.class).name("time") .description("An optional time when this policy should be first executed, formatted as HH:mm:ss") .build(); public static final ConfigKey<Duration> WAIT = ConfigKeys.builder(Duration.class).name("wait").description( "An optional duration after which this policy should be first executed. The time config takes precedence if present") .constraint(Predicates.or(Predicates.isNull(), DurationPredicates.positive())).build(); public static final ConfigKey<AttributeSensor<Boolean>> START_SENSOR = ConfigKeys .builder(new TypeToken<AttributeSensor<Boolean>>() { }).name("start.sensor") .description("The sensor which should trigger starting the periodic execution scheduler") .defaultValue(Startable.SERVICE_UP).build(); public static final ConfigKey<Boolean> RUNNING = ConfigKeys.builder(Boolean.class).name("running") .description("[INTERNAL] Set if the executor has started").defaultValue(Boolean.FALSE) .reconfigurable(true).build(); public static final ConfigKey<List<Long>> SCHEDULED = ConfigKeys.builder(new TypeToken<List<Long>>() { }).name("scheduled").description("List of all scheduled execution start times").defaultValue(ImmutableList.of()) .reconfigurable(true).build(); protected AtomicBoolean running; protected ScheduledExecutorService executor; protected Effector<?> effector; public AbstractScheduledEffectorPolicy() { LOG.debug("Created new scheduled effector policy"); } @Override public void init() { setup(); } @Override public void rebind() { // Called before setEntity; therefore don't do any real work here that might cause us to reference the entity setup(); } public void setup() { if (executor != null) { executor.shutdownNow(); } executor = Executors.newSingleThreadScheduledExecutor(); running = new AtomicBoolean(false); } @Override public void setEntity(EntityLocal entity) { super.setEntity(entity); effector = getEffector(); if (Boolean.TRUE.equals(config().get(RUNNING))) { running.set(true); resubmitOnResume(); } AttributeSensor<Boolean> sensor = config().get(START_SENSOR); subscriptions().subscribe(ImmutableMap.of("notifyOfInitialValue", true), entity, sensor, this); } @Override public void resume() { super.resume(); if (running.get()) { resubmitOnResume(); } } protected List<Long> resubmitOnResume() { List<Long> scheduled = config().get(SCHEDULED); List<Long> updatedScheduled = MutableList.copyOf(scheduled); for (Long when : scheduled) { Duration wait = Duration.millis(when - System.currentTimeMillis()); if (wait.isPositive()) { scheduleInExecutor(wait); } else { updatedScheduled.remove(when); } } config().set(SCHEDULED, updatedScheduled); return updatedScheduled; } @Override protected <T> void doReconfigureConfig(ConfigKey<T> key, T val) { if (key.isReconfigurable()) { return; } else { throw new UnsupportedOperationException( "Reconfiguring key " + key.getName() + " not supported on " + getClass().getSimpleName()); } } @Override public void destroy() { executor.shutdownNow(); super.destroy(); } public abstract void start(); protected Effector<?> getEffector() { String effectorName = config().get(EFFECTOR); Maybe<Effector<?>> effector = getEntity().getEntityType().getEffectorByName(effectorName); if (effector.isAbsentOrNull()) { throw new IllegalStateException("Cannot find effector " + effectorName + " on entity " + getEntity()); } return effector.get(); } protected Duration getWaitUntil(String time) { if (time.equalsIgnoreCase(NOW) || time.equalsIgnoreCase(IMMEDIATELY)) { return Duration.ZERO; } try { Calendar now = Calendar.getInstance(); Calendar when = Calendar.getInstance(); Date parsed = parseTime(time); when.setTime(parsed); when.set(now.get(Calendar.YEAR), now.get(Calendar.MONTH), now.get(Calendar.DATE)); if (when.before(now)) { when.add(Calendar.DATE, 1); } return Duration.millis(Math.max(0, when.getTimeInMillis() - now.getTimeInMillis())); } catch (ParseException | NumberFormatException e) { LOG.warn("{}: Time should be formatted as {}: {}", new Object[] { this, TIME_FORMAT, e.getMessage() }); throw Exceptions.propagate(e); } } protected Date parseTime(String time) throws ParseException { boolean formatted = time.contains(":"); // FIXME deprecated TimeDuration coercion if (formatted) { synchronized (FORMATTER) { // DateFormat is not thread-safe; docs say to use one-per-thread, or to synchronize externally return FORMATTER.parse(time); } } else { return new Date(Long.parseLong(time) * 1000); } } protected void schedule(Duration wait) { List<Long> scheduled = MutableList.copyOf(config().get(SCHEDULED)); scheduled.add(System.currentTimeMillis() + wait.toMilliseconds()); config().set(SCHEDULED, scheduled); scheduleInExecutor(wait); } private void scheduleInExecutor(Duration wait) { executor.schedule(this, wait.toMilliseconds(), TimeUnit.MILLISECONDS); } @Override public synchronized void run() { if (effector == null) return; if (!(isRunning() && getManagementContext().isRunning())) return; try { ConfigBag bag = ResolvingConfigBag.newInstanceExtending(getManagementContext(), config().getBag()); Map<String, Object> args = EntityInitializers.resolve(bag, EFFECTOR_ARGUMENTS); LOG.debug("{}: Resolving arguments for {}: {}", new Object[] { this, effector.getName(), Iterables.toString(args.keySet()) }); Map<String, Object> resolved = (Map) Tasks.resolving(args, Object.class).deep(true, true) .context(entity).get(); LOG.debug("{}: Invoking effector on {}, {}({})", new Object[] { this, entity, effector.getName(), resolved }); Object result = entity.invoke(effector, resolved).getUnchecked(); LOG.debug("{}: Effector {} returned {}", new Object[] { this, effector.getName(), result }); } catch (RuntimeInterruptedException rie) { // Gracefully stop Thread.currentThread().interrupt(); } catch (Throwable t) { LOG.warn("{}: Exception running {}: {}", new Object[] { this, effector.getName(), t.getMessage() }); Exceptions.propagate(t); } } @Override public void onEvent(SensorEvent<Object> event) { LOG.debug("{}: Got event {}", this, event); AttributeSensor<Boolean> sensor = config().get(START_SENSOR); if (event.getSensor().getName().equals(sensor.getName())) { Boolean start = Boolean.TRUE.equals(event.getValue()); if (start && running.compareAndSet(false, true)) { config().set(RUNNING, true); start(); } } } }