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.loadbalancing; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.Map; import java.util.Set; import java.util.concurrent.locks.ReentrantLock; import org.apache.brooklyn.api.entity.Entity; import org.apache.brooklyn.api.location.Location; import org.apache.brooklyn.api.sensor.AttributeSensor; import org.apache.brooklyn.core.entity.Attributes; import org.apache.brooklyn.entity.group.AbstractGroupImpl; import org.apache.brooklyn.util.collections.MutableList; import org.apache.brooklyn.util.time.Time; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.base.Predicates; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; import com.google.common.collect.Lists; import com.google.common.collect.Maps; import com.google.common.collect.Sets; public class MockContainerEntityImpl extends AbstractGroupImpl implements MockContainerEntity { private static final Logger LOG = LoggerFactory.getLogger(MockContainerEntity.class); volatile boolean offloading; volatile boolean running; ReentrantLock _lock = new ReentrantLock(); @Override @Deprecated public <T> T setAttribute(AttributeSensor<T> attribute, T val) { if (LOG.isDebugEnabled()) LOG.debug("Mocks: container {} setting {} to {}", new Object[] { this, attribute, val }); return super.sensors().set(attribute, val); } @Override public void lock() { _lock.lock(); if (!running) { _lock.unlock(); throw new IllegalStateException("Container lock " + this + "; it is not running"); } } @Override public void unlock() { _lock.unlock(); } @Override public int getWorkrate() { int result = 0; for (Entity member : getMembers()) { Integer memberMetric = member.getAttribute(MockItemEntity.TEST_METRIC); result += ((memberMetric != null) ? memberMetric : 0); } return result; } @Override public Map<Entity, Double> getItemUsage() { Map<Entity, Double> result = Maps.newLinkedHashMap(); for (Entity member : getMembers()) { Map<Entity, Double> memberItemUsage = member.getAttribute(MockItemEntity.ITEM_USAGE_METRIC); if (memberItemUsage != null) { for (Map.Entry<Entity, Double> entry : memberItemUsage.entrySet()) { double val = (result.containsKey(entry.getKey()) ? result.get(entry.getKey()) : 0d); val += ((entry.getValue() != null) ? entry.getValue() : 0); result.put(entry.getKey(), val); } } } return result; } @Override public void addItem(Entity item) { if (LOG.isDebugEnabled()) LOG.debug("Mocks: adding item {} to container {}", item, this); if (!running || offloading) throw new IllegalStateException( "Container " + getDisplayName() + " is not running; cannot add item " + item); addMember(item); sensors().emit(ITEM_ADDED, item); } @Override public void removeItem(Entity item) { if (LOG.isDebugEnabled()) LOG.debug("Mocks: removing item {} from container {}", item, this); if (!running) throw new IllegalStateException( "Container " + getDisplayName() + " is not running; cannot remove item " + item); removeMember(item); sensors().emit(ITEM_REMOVED, item); } @SuppressWarnings({ "unchecked", "rawtypes" }) @Override public Set<Movable> getBalanceableItems() { return (Set) Sets.newLinkedHashSet(getMembers()); } public String toString() { return "MockContainer[" + getDisplayName() + "]"; } private long getDelay() { return getConfig(DELAY); } @Override public void start(Collection<? extends Location> locs) { if (LOG.isDebugEnabled()) LOG.debug("Mocks: starting container {}", this); _lock.lock(); try { Time.sleep(getDelay()); running = true; addLocations(locs); sensors().emit(Attributes.LOCATION_CHANGED, null); sensors().set(SERVICE_UP, true); } finally { _lock.unlock(); } } @Override public void stop() { if (LOG.isDebugEnabled()) LOG.debug("Mocks: stopping container {}", this); _lock.lock(); try { running = false; Time.sleep(getDelay()); sensors().set(SERVICE_UP, false); } finally { _lock.unlock(); } } private void stopWithoutLock() { running = false; Time.sleep(getDelay()); sensors().set(SERVICE_UP, false); } public void offloadAndStop(final MockContainerEntity otherContainer) { if (LOG.isDebugEnabled()) LOG.debug("Mocks: offloading container {} to {} (items {})", new Object[] { this, otherContainer, getBalanceableItems() }); runWithLock(ImmutableList.of(this, otherContainer), new Runnable() { public void run() { offloading = false; for (Movable item : getBalanceableItems()) { ((MockItemEntity) item).moveNonEffector(otherContainer); } if (LOG.isDebugEnabled()) LOG.debug("Mocks: stopping offloaded container {}", this); stopWithoutLock(); } }); } @Override public void restart() { if (LOG.isDebugEnabled()) LOG.debug("Mocks: restarting {}", this); throw new UnsupportedOperationException(); } public static void runWithLock(List<MockContainerEntity> entitiesToLock, Runnable r) { List<MockContainerEntity> entitiesToLockCopy = MutableList .copyOf(Iterables.filter(entitiesToLock, Predicates.notNull())); List<MockContainerEntity> entitiesLocked = Lists.newArrayList(); Collections.sort(entitiesToLockCopy, new Comparator<MockContainerEntity>() { public int compare(MockContainerEntity o1, MockContainerEntity o2) { return o1.getId().compareTo(o2.getId()); } }); try { for (MockContainerEntity it : entitiesToLockCopy) { it.lock(); entitiesLocked.add(it); } r.run(); } finally { for (MockContainerEntity it : entitiesLocked) { it.unlock(); } } } }