org.apache.qpid.server.model.adapter.VirtualHostAdapter.java Source code

Java tutorial

Introduction

Here is the source code for org.apache.qpid.server.model.adapter.VirtualHostAdapter.java

Source

/*
 *
 * 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.qpid.server.model.adapter;

import java.io.File;
import java.lang.reflect.Type;
import java.security.AccessControlException;
import java.security.Principal;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.UUID;

import org.apache.commons.configuration.CompositeConfiguration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.commons.configuration.SystemConfiguration;
import org.apache.log4j.Logger;
import org.apache.qpid.AMQException;
import org.apache.qpid.framing.FieldTable;
import org.apache.qpid.server.configuration.IllegalConfigurationException;
import org.apache.qpid.server.configuration.VirtualHostConfiguration;
import org.apache.qpid.server.configuration.XmlConfigurationUtilities.MyConfiguration;
import org.apache.qpid.server.connection.IConnectionRegistry;
import org.apache.qpid.server.exchange.ExchangeRegistry;
import org.apache.qpid.server.message.ServerMessage;
import org.apache.qpid.server.model.Broker;
import org.apache.qpid.server.model.ConfiguredObject;
import org.apache.qpid.server.model.Connection;
import org.apache.qpid.server.model.Exchange;
import org.apache.qpid.server.model.IntegrityViolationException;
import org.apache.qpid.server.model.LifetimePolicy;
import org.apache.qpid.server.model.Port;
import org.apache.qpid.server.model.Protocol;
import org.apache.qpid.server.model.Queue;
import org.apache.qpid.server.model.QueueType;
import org.apache.qpid.server.model.State;
import org.apache.qpid.server.model.Statistics;
import org.apache.qpid.server.model.UUIDGenerator;
import org.apache.qpid.server.model.VirtualHost;
import org.apache.qpid.server.model.VirtualHostAlias;
import org.apache.qpid.server.configuration.updater.TaskExecutor;
import org.apache.qpid.server.plugin.ExchangeType;
import org.apache.qpid.server.protocol.AMQConnectionModel;
import org.apache.qpid.server.queue.AMQQueue;
import org.apache.qpid.server.queue.AMQQueueFactory;
import org.apache.qpid.server.queue.QueueEntry;
import org.apache.qpid.server.queue.QueueRegistry;
import org.apache.qpid.server.security.SecurityManager;
import org.apache.qpid.server.security.auth.AuthenticatedPrincipal;
import org.apache.qpid.server.stats.StatisticsGatherer;
import org.apache.qpid.server.store.MessageStore;
import org.apache.qpid.server.txn.LocalTransaction;
import org.apache.qpid.server.txn.ServerTransaction;
import org.apache.qpid.server.util.MapValueConverter;
import org.apache.qpid.server.virtualhost.VirtualHostImpl;
import org.apache.qpid.server.virtualhost.VirtualHostRegistry;
import org.apache.qpid.util.FileUtils;

public final class VirtualHostAdapter extends AbstractAdapter
        implements VirtualHost, ExchangeRegistry.RegistryChangeListener, QueueRegistry.RegistryChangeListener,
        IConnectionRegistry.RegistryChangeListener {

    private static final Logger LOGGER = Logger.getLogger(VirtualHostAdapter.class);

    @SuppressWarnings("serial")
    public static final Map<String, Type> ATTRIBUTE_TYPES = Collections
            .unmodifiableMap(new HashMap<String, Type>() {
                {
                    put(NAME, String.class);
                    put(STORE_PATH, String.class);
                    put(STORE_TYPE, String.class);
                    put(CONFIG_PATH, String.class);
                    put(STATE, State.class);
                }
            });

    private org.apache.qpid.server.virtualhost.VirtualHost _virtualHost;

    private final Map<AMQConnectionModel, ConnectionAdapter> _connectionAdapters = new HashMap<AMQConnectionModel, ConnectionAdapter>();

    private final Map<AMQQueue, QueueAdapter> _queueAdapters = new HashMap<AMQQueue, QueueAdapter>();

    private final Map<org.apache.qpid.server.exchange.Exchange, ExchangeAdapter> _exchangeAdapters = new HashMap<org.apache.qpid.server.exchange.Exchange, ExchangeAdapter>();
    private StatisticsAdapter _statistics;
    private final Broker _broker;
    private final List<VirtualHostAlias> _aliases = new ArrayList<VirtualHostAlias>();
    private StatisticsGatherer _brokerStatisticsGatherer;

    public VirtualHostAdapter(UUID id, Map<String, Object> attributes, Broker broker,
            StatisticsGatherer brokerStatisticsGatherer, TaskExecutor taskExecutor) {
        super(id, null, MapValueConverter.convert(attributes, ATTRIBUTE_TYPES), taskExecutor);
        validateAttributes();
        _broker = broker;
        _brokerStatisticsGatherer = brokerStatisticsGatherer;
        addParent(Broker.class, broker);
    }

    private void validateAttributes() {
        String name = getName();
        if (name == null || "".equals(name.trim())) {
            throw new IllegalConfigurationException("Virtual host name must be specified");
        }

        String configurationFile = (String) getAttribute(CONFIG_PATH);
        String storeType = (String) getAttribute(STORE_TYPE);
        boolean invalidAttributes = false;
        if (configurationFile == null) {
            if (storeType == null) {
                invalidAttributes = true;
            }
        } else {
            if (storeType != null) {
                invalidAttributes = true;
            }
        }
        if (invalidAttributes) {
            throw new IllegalConfigurationException(
                    "Please specify either the 'configPath' attribute or 'storeType' and 'storePath' attributes");
        }
    }

    private void populateExchanges() {
        Collection<org.apache.qpid.server.exchange.Exchange> actualExchanges = _virtualHost.getExchangeRegistry()
                .getExchanges();

        synchronized (_exchangeAdapters) {
            for (org.apache.qpid.server.exchange.Exchange exchange : actualExchanges) {
                if (!_exchangeAdapters.containsKey(exchange)) {
                    _exchangeAdapters.put(exchange, new ExchangeAdapter(this, exchange));
                }
            }
        }
    }

    private void populateQueues() {
        Collection<AMQQueue> actualQueues = _virtualHost.getQueueRegistry().getQueues();
        if (actualQueues != null) {
            synchronized (_queueAdapters) {
                for (AMQQueue queue : actualQueues) {
                    if (!_queueAdapters.containsKey(queue)) {
                        _queueAdapters.put(queue, new QueueAdapter(this, queue));
                    }
                }
            }
        }
    }

    public Collection<VirtualHostAlias> getAliases() {
        return Collections.unmodifiableCollection(_aliases);
    }

    public Collection<Connection> getConnections() {
        synchronized (_connectionAdapters) {
            return new ArrayList<Connection>(_connectionAdapters.values());
        }

    }

    public Collection<Queue> getQueues() {
        synchronized (_queueAdapters) {
            return new ArrayList<Queue>(_queueAdapters.values());
        }
    }

    public Collection<Exchange> getExchanges() {
        synchronized (_exchangeAdapters) {
            return new ArrayList<Exchange>(_exchangeAdapters.values());
        }
    }

    public Exchange createExchange(Map<String, Object> attributes)
            throws AccessControlException, IllegalArgumentException {
        attributes = new HashMap<String, Object>(attributes);

        String name = MapValueConverter.getStringAttribute(Exchange.NAME, attributes, null);
        State state = MapValueConverter.getEnumAttribute(State.class, Exchange.STATE, attributes, State.ACTIVE);
        boolean durable = MapValueConverter.getBooleanAttribute(Exchange.DURABLE, attributes, false);
        LifetimePolicy lifetime = MapValueConverter.getEnumAttribute(LifetimePolicy.class, Exchange.LIFETIME_POLICY,
                attributes, LifetimePolicy.PERMANENT);
        String type = MapValueConverter.getStringAttribute(Exchange.TYPE, attributes, null);
        long ttl = MapValueConverter.getLongAttribute(Exchange.TIME_TO_LIVE, attributes, 0l);

        attributes.remove(Exchange.NAME);
        attributes.remove(Exchange.STATE);
        attributes.remove(Exchange.DURABLE);
        attributes.remove(Exchange.LIFETIME_POLICY);
        attributes.remove(Exchange.TYPE);
        attributes.remove(Exchange.TIME_TO_LIVE);

        return createExchange(name, state, durable, lifetime, ttl, type, attributes);
    }

    public Exchange createExchange(final String name, final State initialState, final boolean durable,
            final LifetimePolicy lifetime, final long ttl, final String type, final Map<String, Object> attributes)
            throws AccessControlException, IllegalArgumentException {
        checkVHostStateIsActive();

        try {
            ExchangeRegistry exchangeRegistry = _virtualHost.getExchangeRegistry();
            if (exchangeRegistry.isReservedExchangeName(name)) {
                throw new UnsupportedOperationException("'" + name + "' is a reserved exchange name");
            }
            synchronized (exchangeRegistry) {
                org.apache.qpid.server.exchange.Exchange exchange = exchangeRegistry.getExchange(name);
                if (exchange != null) {
                    throw new IllegalArgumentException("Exchange with name '" + name + "' already exists");
                }
                exchange = _virtualHost.getExchangeFactory().createExchange(name, type, durable,
                        lifetime == LifetimePolicy.AUTO_DELETE);
                _virtualHost.getExchangeRegistry().registerExchange(exchange);
                if (durable) {
                    _virtualHost.getMessageStore().createExchange(exchange);
                }
                synchronized (_exchangeAdapters) {
                    return _exchangeAdapters.get(exchange);
                }
            }
        } catch (AMQException e) {
            throw new IllegalArgumentException(e);
        }
    }

    public Queue createQueue(Map<String, Object> attributes)
            throws AccessControlException, IllegalArgumentException {
        attributes = new HashMap<String, Object>(attributes);

        if (attributes.containsKey(Queue.TYPE)) {
            String typeAttribute = MapValueConverter.getStringAttribute(Queue.TYPE, attributes, null);
            QueueType queueType = null;
            try {
                queueType = QueueType.valueOf(typeAttribute.toUpperCase());
            } catch (Exception e) {
                throw new IllegalArgumentException("Unsupported queue type :" + typeAttribute);
            }
            if (queueType == QueueType.LVQ && attributes.get(Queue.LVQ_KEY) == null) {
                attributes.put(Queue.LVQ_KEY, AMQQueueFactory.QPID_LVQ_KEY);
            } else if (queueType == QueueType.PRIORITY && attributes.get(Queue.PRIORITIES) == null) {
                attributes.put(Queue.PRIORITIES, 10);
            } else if (queueType == QueueType.SORTED && attributes.get(Queue.SORT_KEY) == null) {
                throw new IllegalArgumentException("Sort key is not specified for sorted queue");
            }
        }
        String name = MapValueConverter.getStringAttribute(Queue.NAME, attributes, null);
        State state = MapValueConverter.getEnumAttribute(State.class, Queue.STATE, attributes, State.ACTIVE);
        boolean durable = MapValueConverter.getBooleanAttribute(Queue.DURABLE, attributes, false);
        LifetimePolicy lifetime = MapValueConverter.getEnumAttribute(LifetimePolicy.class, Queue.LIFETIME_POLICY,
                attributes, LifetimePolicy.PERMANENT);
        long ttl = MapValueConverter.getLongAttribute(Queue.TIME_TO_LIVE, attributes, 0l);
        boolean exclusive = MapValueConverter.getBooleanAttribute(Queue.EXCLUSIVE, attributes, false);

        attributes.remove(Queue.NAME);
        attributes.remove(Queue.STATE);
        attributes.remove(Queue.DURABLE);
        attributes.remove(Queue.LIFETIME_POLICY);
        attributes.remove(Queue.TIME_TO_LIVE);

        List<String> attrNames = new ArrayList<String>(attributes.keySet());
        for (String attr : attrNames) {
            if (QueueAdapter.ATTRIBUTE_MAPPINGS.containsKey(attr)) {
                attributes.put(QueueAdapter.ATTRIBUTE_MAPPINGS.get(attr), attributes.remove(attr));
            }
        }

        return createQueue(name, state, durable, exclusive, lifetime, ttl, attributes);
    }

    public Queue createQueue(final String name, final State initialState, final boolean durable, boolean exclusive,
            final LifetimePolicy lifetime, final long ttl, final Map<String, Object> attributes)
            throws AccessControlException, IllegalArgumentException {
        checkVHostStateIsActive();

        String owner = null;
        if (exclusive) {
            Principal authenticatedPrincipal = AuthenticatedPrincipal
                    .getOptionalAuthenticatedPrincipalFromSubject(SecurityManager.getThreadSubject());
            if (authenticatedPrincipal != null) {
                owner = authenticatedPrincipal.getName();
            }
        }
        try {
            QueueRegistry queueRegistry = _virtualHost.getQueueRegistry();
            synchronized (queueRegistry) {
                if (_virtualHost.getQueueRegistry().getQueue(name) != null) {
                    throw new IllegalArgumentException("Queue with name " + name + " already exists");
                }
                AMQQueue queue = AMQQueueFactory.createAMQQueueImpl(
                        UUIDGenerator.generateQueueUUID(name, _virtualHost.getName()), name, durable, owner,
                        lifetime == LifetimePolicy.AUTO_DELETE, exclusive, _virtualHost, attributes);
                _virtualHost.getBindingFactory().addBinding(name, queue,
                        _virtualHost.getExchangeRegistry().getDefaultExchange(), null);

                if (durable) {
                    _virtualHost.getMessageStore().createQueue(queue, FieldTable.convertToFieldTable(attributes));
                }
                synchronized (_queueAdapters) {
                    return _queueAdapters.get(queue);
                }
            }

        } catch (AMQException e) {
            throw new IllegalArgumentException(e);
        }

    }

    public String getName() {
        return (String) getAttribute(NAME);
    }

    public String setName(final String currentName, final String desiredName)
            throws IllegalStateException, AccessControlException {
        throw new IllegalStateException();
    }

    @Override
    public State getActualState() {
        if (_virtualHost == null) {
            State state = (State) super.getAttribute(STATE);
            if (state == null) {
                return State.INITIALISING;
            }
            return state;
        } else {
            org.apache.qpid.server.virtualhost.State implementationState = _virtualHost.getState();
            switch (implementationState) {
            case INITIALISING:
                return State.INITIALISING;
            case ACTIVE:
                return State.ACTIVE;
            case PASSIVE:
                return State.QUIESCED;
            case STOPPED:
                return State.STOPPED;
            default:
                // unexpected state
                return null;
            }
        }
    }

    public boolean isDurable() {
        return true;
    }

    public void setDurable(final boolean durable)
            throws IllegalStateException, AccessControlException, IllegalArgumentException {
        throw new IllegalStateException();
    }

    public LifetimePolicy getLifetimePolicy() {
        return LifetimePolicy.PERMANENT;
    }

    public LifetimePolicy setLifetimePolicy(final LifetimePolicy expected, final LifetimePolicy desired)
            throws IllegalStateException, AccessControlException, IllegalArgumentException {
        throw new IllegalStateException();
    }

    public long getTimeToLive() {
        return 0;
    }

    public long setTimeToLive(final long expected, final long desired)
            throws IllegalStateException, AccessControlException, IllegalArgumentException {
        throw new IllegalStateException();
    }

    public Statistics getStatistics() {
        return _statistics;
    }

    @Override
    public <C extends ConfiguredObject> Collection<C> getChildren(Class<C> clazz) {
        if (clazz == Exchange.class) {
            return (Collection<C>) getExchanges();
        } else if (clazz == Queue.class) {
            return (Collection<C>) getQueues();
        } else if (clazz == Connection.class) {
            return (Collection<C>) getConnections();
        } else if (clazz == VirtualHostAlias.class) {
            return (Collection<C>) getAliases();
        } else {
            return Collections.emptySet();
        }
    }

    @Override
    public <C extends ConfiguredObject> C addChild(Class<C> childClass, Map<String, Object> attributes,
            ConfiguredObject... otherParents) {
        if (childClass == Exchange.class) {
            return (C) createExchange(attributes);
        } else if (childClass == Queue.class) {
            return (C) createQueue(attributes);
        } else if (childClass == VirtualHostAlias.class) {
            throw new UnsupportedOperationException();
        } else if (childClass == Connection.class) {
            throw new UnsupportedOperationException();
        }
        throw new IllegalArgumentException("Cannot create a child of class " + childClass.getSimpleName());
    }

    public void exchangeRegistered(org.apache.qpid.server.exchange.Exchange exchange) {
        ExchangeAdapter adapter = null;
        synchronized (_exchangeAdapters) {
            if (!_exchangeAdapters.containsKey(exchange)) {
                adapter = new ExchangeAdapter(this, exchange);
                _exchangeAdapters.put(exchange, adapter);

            }

        }
        if (adapter != null) {
            childAdded(adapter);
        }

    }

    public void exchangeUnregistered(org.apache.qpid.server.exchange.Exchange exchange) {
        ExchangeAdapter adapter;
        synchronized (_exchangeAdapters) {
            adapter = _exchangeAdapters.remove(exchange);

        }

        if (adapter != null) {
            childRemoved(adapter);
        }
    }

    public void queueRegistered(AMQQueue queue) {
        QueueAdapter adapter = null;
        synchronized (_queueAdapters) {
            if (!_queueAdapters.containsKey(queue)) {
                adapter = new QueueAdapter(this, queue);
                _queueAdapters.put(queue, adapter);

            }

        }
        if (adapter != null) {
            childAdded(adapter);
        }

    }

    public void queueUnregistered(AMQQueue queue) {

        QueueAdapter adapter;
        synchronized (_queueAdapters) {
            adapter = _queueAdapters.remove(queue);

        }

        if (adapter != null) {
            childRemoved(adapter);
        }
    }

    public void connectionRegistered(AMQConnectionModel connection) {
        ConnectionAdapter adapter = null;
        synchronized (_connectionAdapters) {
            if (!_connectionAdapters.containsKey(connection)) {
                adapter = new ConnectionAdapter(connection, getTaskExecutor());
                _connectionAdapters.put(connection, adapter);

            }

        }
        if (adapter != null) {
            childAdded(adapter);
        }
    }

    public void connectionUnregistered(AMQConnectionModel connection) {

        ConnectionAdapter adapter;
        synchronized (_connectionAdapters) {
            adapter = _connectionAdapters.remove(connection);

        }

        if (adapter != null) {
            childRemoved(adapter);
        }
    }

    QueueAdapter getQueueAdapter(AMQQueue queue) {
        synchronized (_queueAdapters) {
            return _queueAdapters.get(queue);
        }
    }

    public Collection<String> getExchangeTypes() {
        Collection<ExchangeType<? extends org.apache.qpid.server.exchange.Exchange>> types = _virtualHost
                .getExchangeFactory().getRegisteredTypes();

        Collection<String> exchangeTypes = new ArrayList<String>();

        for (ExchangeType<? extends org.apache.qpid.server.exchange.Exchange> type : types) {
            exchangeTypes.add(type.getName().asString());
        }
        return Collections.unmodifiableCollection(exchangeTypes);
    }

    public void executeTransaction(TransactionalOperation op) {
        MessageStore store = _virtualHost.getMessageStore();
        final LocalTransaction txn = new LocalTransaction(store);

        op.withinTransaction(new Transaction() {
            public void dequeue(final QueueEntry entry) {
                if (entry.acquire()) {
                    txn.dequeue(entry.getQueue(), entry.getMessage(), new ServerTransaction.Action() {
                        public void postCommit() {
                            entry.discard();
                        }

                        public void onRollback() {
                        }
                    });
                }
            }

            public void copy(QueueEntry entry, Queue queue) {
                final ServerMessage message = entry.getMessage();
                final AMQQueue toQueue = ((QueueAdapter) queue).getAMQQueue();

                txn.enqueue(toQueue, message, new ServerTransaction.Action() {
                    public void postCommit() {
                        try {
                            toQueue.enqueue(message);
                        } catch (AMQException e) {
                            throw new RuntimeException(e);
                        }
                    }

                    public void onRollback() {
                    }
                });

            }

            public void move(final QueueEntry entry, Queue queue) {
                final ServerMessage message = entry.getMessage();
                final AMQQueue toQueue = ((QueueAdapter) queue).getAMQQueue();
                if (entry.acquire()) {
                    txn.enqueue(toQueue, message, new ServerTransaction.Action() {

                        public void postCommit() {
                            try {
                                toQueue.enqueue(message);
                            } catch (AMQException e) {
                                throw new RuntimeException(e);
                            }
                        }

                        public void onRollback() {
                            entry.release();
                        }
                    });
                    txn.dequeue(entry.getQueue(), message, new ServerTransaction.Action() {

                        public void postCommit() {
                            entry.discard();
                        }

                        public void onRollback() {

                        }
                    });
                }
            }

        });
        txn.commit();
    }

    org.apache.qpid.server.virtualhost.VirtualHost getVirtualHost() {
        return _virtualHost;
    }

    @Override
    public Object getAttribute(String name) {
        if (ID.equals(name)) {
            return getId();
        } else if (STATE.equals(name)) {
            return getActualState();
        } else if (DURABLE.equals(name)) {
            return isDurable();
        } else if (LIFETIME_POLICY.equals(name)) {
            return LifetimePolicy.PERMANENT;
        } else if (TIME_TO_LIVE.equals(name)) {
            // TODO
        } else if (CREATED.equals(name)) {
            // TODO
        } else if (UPDATED.equals(name)) {
            // TODO
        } else if (_virtualHost != null) {
            return getAttributeFromVirtualHostImplementation(name);
        }
        return super.getAttribute(name);
    }

    private Object getAttributeFromVirtualHostImplementation(String name) {
        if (SUPPORTED_EXCHANGE_TYPES.equals(name)) {
            List<String> types = new ArrayList<String>();
            for (@SuppressWarnings("rawtypes")
            ExchangeType type : _virtualHost.getExchangeFactory().getRegisteredTypes()) {
                types.add(type.getName().asString());
            }
            return Collections.unmodifiableCollection(types);
        } else if (SUPPORTED_QUEUE_TYPES.equals(name)) {
            // TODO
        } else if (DEAD_LETTER_QUEUE_ENABLED.equals(name)) {
            return _virtualHost.getConfiguration().isDeadLetterQueueEnabled();
        } else if (HOUSEKEEPING_CHECK_PERIOD.equals(name)) {
            return _virtualHost.getConfiguration().getHousekeepingCheckPeriod();
        } else if (MAXIMUM_DELIVERY_ATTEMPTS.equals(name)) {
            return _virtualHost.getConfiguration().getMaxDeliveryCount();
        } else if (QUEUE_FLOW_CONTROL_SIZE_BYTES.equals(name)) {
            return _virtualHost.getConfiguration().getCapacity();
        } else if (QUEUE_FLOW_RESUME_SIZE_BYTES.equals(name)) {
            return _virtualHost.getConfiguration().getFlowResumeCapacity();
        } else if (STORE_TYPE.equals(name)) {
            return _virtualHost.getMessageStore().getStoreType();
        } else if (STORE_PATH.equals(name)) {
            return _virtualHost.getMessageStore().getStoreLocation();
        } else if (STORE_TRANSACTION_IDLE_TIMEOUT_CLOSE.equals(name)) {
            return _virtualHost.getConfiguration().getTransactionTimeoutIdleClose();
        } else if (STORE_TRANSACTION_IDLE_TIMEOUT_WARN.equals(name)) {
            return _virtualHost.getConfiguration().getTransactionTimeoutIdleWarn();
        } else if (STORE_TRANSACTION_OPEN_TIMEOUT_CLOSE.equals(name)) {
            return _virtualHost.getConfiguration().getTransactionTimeoutOpenClose();
        } else if (STORE_TRANSACTION_OPEN_TIMEOUT_WARN.equals(name)) {
            return _virtualHost.getConfiguration().getTransactionTimeoutOpenWarn();
        } else if (ALERT_REPEAT_GAP.equals(name)) {
            return _virtualHost.getConfiguration().getMinimumAlertRepeatGap();
        } else if (ALERT_THRESHOLD_MESSAGE_AGE.equals(name)) {
            return _virtualHost.getConfiguration().getMaximumMessageAge();
        } else if (ALERT_THRESHOLD_MESSAGE_SIZE.equals(name)) {
            return _virtualHost.getConfiguration().getMaximumMessageSize();
        } else if (ALERT_THRESHOLD_QUEUE_DEPTH_BYTES.equals(name)) {
            return _virtualHost.getConfiguration().getMaximumQueueDepth();
        } else if (ALERT_THRESHOLD_QUEUE_DEPTH_MESSAGES.equals(name)) {
            return _virtualHost.getConfiguration().getMaximumMessageCount();
        }
        return super.getAttribute(name);
    }

    @Override
    public Collection<String> getAttributeNames() {
        return AVAILABLE_ATTRIBUTES;
    }

    private void checkVHostStateIsActive() {
        if (!org.apache.qpid.server.virtualhost.State.ACTIVE.equals(_virtualHost.getState())) {
            throw new IllegalStateException(
                    "The virtual hosts state of " + _virtualHost.getState() + " does not permit this operation.");
        }
    }

    private static class VirtualHostStatisticsAdapter extends StatisticsAdapter {
        private final org.apache.qpid.server.virtualhost.VirtualHost _vhost;

        private static final Collection<String> VHOST_STATS = Arrays.asList(VirtualHost.QUEUE_COUNT,
                VirtualHost.EXCHANGE_COUNT, VirtualHost.CONNECTION_COUNT);

        public VirtualHostStatisticsAdapter(org.apache.qpid.server.virtualhost.VirtualHost virtualHost) {
            super(virtualHost);
            _vhost = virtualHost;
        }

        @Override
        public Collection<String> getStatisticNames() {
            Set<String> stats = new HashSet<String>(super.getStatisticNames());
            stats.addAll(VHOST_STATS);
            return stats;
        }

        @Override
        public Object getStatistic(String name) {
            if (VirtualHost.QUEUE_COUNT.equals(name)) {
                return _vhost.getQueueRegistry().getQueues().size();
            } else if (VirtualHost.EXCHANGE_COUNT.equals(name)) {
                return _vhost.getExchangeRegistry().getExchanges().size();
            } else if (VirtualHost.CONNECTION_COUNT.equals(name)) {
                return _vhost.getConnectionRegistry().getConnections().size();
            } else {
                return super.getStatistic(name);
            }
        }
    }

    @Override
    protected boolean setState(State currentState, State desiredState) {
        if (desiredState == State.ACTIVE) {
            activate();
            return true;
        } else if (desiredState == State.STOPPED) {
            if (_virtualHost != null) {
                try {
                    _virtualHost.close();
                } finally {
                    _broker.getVirtualHostRegistry().unregisterVirtualHost(_virtualHost);
                }
            }
            return true;
        } else if (desiredState == State.DELETED) {
            //TODO: add ACL check to authorize the operation

            String hostName = getName();

            if (hostName.equals(_broker.getAttribute(Broker.DEFAULT_VIRTUAL_HOST))) {
                throw new IntegrityViolationException("Cannot delete default virtual host '" + hostName + "'");
            }
            if (_virtualHost != null
                    && _virtualHost.getState() == org.apache.qpid.server.virtualhost.State.ACTIVE) {
                setDesiredState(currentState, State.STOPPED);
            }
            _virtualHost = null;
            setAttribute(VirtualHost.STATE, getActualState(), State.DELETED);
            return true;
        }
        return false;
    }

    private void activate() {
        VirtualHostRegistry virtualHostRegistry = _broker.getVirtualHostRegistry();
        String virtualHostName = getName();
        try {
            VirtualHostConfiguration configuration = createVirtualHostConfiguration(virtualHostName);
            _virtualHost = new VirtualHostImpl(_broker.getVirtualHostRegistry(), _brokerStatisticsGatherer,
                    _broker.getSecurityManager(), configuration);
        } catch (Exception e) {
            throw new RuntimeException("Failed to create virtual host " + virtualHostName, e);
        }

        virtualHostRegistry.registerVirtualHost(_virtualHost);

        _statistics = new VirtualHostStatisticsAdapter(_virtualHost);
        _virtualHost.getQueueRegistry().addRegistryChangeListener(this);
        populateQueues();
        _virtualHost.getExchangeRegistry().addRegistryChangeListener(this);
        populateExchanges();
        _virtualHost.getConnectionRegistry().addRegistryChangeListener(this);

        synchronized (_aliases) {
            for (Port port : _broker.getPorts()) {
                if (Protocol.hasAmqpProtocol(port.getProtocols())) {
                    _aliases.add(new VirtualHostAliasAdapter(this, port));
                }
            }
        }
    }

    private VirtualHostConfiguration createVirtualHostConfiguration(String virtualHostName)
            throws ConfigurationException {
        VirtualHostConfiguration configuration;
        String configurationFile = (String) getAttribute(CONFIG_PATH);
        if (configurationFile == null) {
            final MyConfiguration basicConfiguration = new MyConfiguration();
            PropertiesConfiguration config = new PropertiesConfiguration();
            config.addProperty("store.type", (String) getAttribute(STORE_TYPE));
            config.addProperty("store.environment-path", (String) getAttribute(STORE_PATH));
            basicConfiguration.addConfiguration(config);

            CompositeConfiguration compositeConfiguration = new CompositeConfiguration();
            compositeConfiguration.addConfiguration(new SystemConfiguration());
            compositeConfiguration.addConfiguration(basicConfiguration);
            configuration = new VirtualHostConfiguration(virtualHostName, compositeConfiguration, _broker);
        } else {
            configuration = new VirtualHostConfiguration(virtualHostName, new File(configurationFile), _broker);
        }
        return configuration;
    }

    @Override
    public SecurityManager getSecurityManager() {
        return _virtualHost.getSecurityManager();
    }

    @Override
    public MessageStore getMessageStore() {
        return _virtualHost.getMessageStore();
    }

    @Override
    protected void changeAttributes(Map<String, Object> attributes) {
        throw new UnsupportedOperationException("Changing attributes on virtualhosts is not supported.");
    }
}