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*
* 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.exchange;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.ListIterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CopyOnWriteArraySet;
import org.apache.log4j.Logger;
import org.apache.qpid.exchange.ExchangeDefaults;
import org.apache.qpid.server.binding.BindingImpl;
import org.apache.qpid.server.filter.Filterable;
import org.apache.qpid.server.message.InstanceProperties;
import org.apache.qpid.server.message.ServerMessage;
import org.apache.qpid.server.model.ManagedObject;
import org.apache.qpid.server.model.ManagedObjectFactoryConstructor;
import org.apache.qpid.server.queue.AMQQueue;
import org.apache.qpid.server.queue.BaseQueue;
import org.apache.qpid.server.virtualhost.VirtualHostImpl;
/**
* An exchange that binds queues based on a set of required headers and header values
* and routes messages to these queues by matching the headers of the message against
* those with which the queues were bound.
* <p>
* <pre>
* The Headers Exchange
*
* Routes messages according to the value/presence of fields in the message header table.
* (Basic and JMS content has a content header field called "headers" that is a table of
* message header fields).
*
* class = "headers"
* routing key is not used
*
* Has the following binding arguments:
*
* the X-match field - if "all", does an AND match (used for GRM), if "any", does an OR match.
* other fields prefixed with "X-" are ignored (and generate a console warning message).
* a field with no value or empty value indicates a match on presence only.
* a field with a value indicates match on field presence and specific value.
*
* Standard instances:
*
* amq.match - pub/sub on field content/value
* </pre>
*/
@ManagedObject( category = false, type = ExchangeDefaults.HEADERS_EXCHANGE_CLASS )
public class HeadersExchange extends AbstractExchange<HeadersExchange>
{
private static final Logger _logger = Logger.getLogger(HeadersExchange.class);
private final ConcurrentMap<String, CopyOnWriteArraySet<BindingImpl>> _bindingsByKey =
new ConcurrentHashMap<String, CopyOnWriteArraySet<BindingImpl>>();
private final CopyOnWriteArrayList<HeadersBinding> _bindingHeaderMatchers =
new CopyOnWriteArrayList<HeadersBinding>();
@ManagedObjectFactoryConstructor
public HeadersExchange(final Map<String, Object> attributes, final VirtualHostImpl vhost)
{
super(attributes, vhost);
}
@Override
public ArrayList<BaseQueue> doRoute(ServerMessage payload,
final String routingKey,
final InstanceProperties instanceProperties)
{
if (_logger.isDebugEnabled())
{
_logger.debug("Exchange " + getName() + ": routing message with headers " + payload.getMessageHeader());
}
LinkedHashSet<BaseQueue> queues = new LinkedHashSet<BaseQueue>();
for (HeadersBinding hb : _bindingHeaderMatchers)
{
if (hb.matches(Filterable.Factory.newInstance(payload,instanceProperties)))
{
BindingImpl b = hb.getBinding();
b.incrementMatches();
if (_logger.isDebugEnabled())
{
_logger.debug("Exchange " + getName() + ": delivering message with headers " +
payload.getMessageHeader() + " to " + b.getAMQQueue().getName());
}
queues.add(b.getAMQQueue());
}
}
return new ArrayList<BaseQueue>(queues);
}
protected void onBind(final BindingImpl binding)
{
String bindingKey = binding.getBindingKey();
AMQQueue queue = binding.getAMQQueue();
assert queue != null;
assert bindingKey != null;
CopyOnWriteArraySet<BindingImpl> bindings = _bindingsByKey.get(bindingKey);
if(bindings == null)
{
bindings = new CopyOnWriteArraySet<BindingImpl>();
CopyOnWriteArraySet<BindingImpl> newBindings;
if((newBindings = _bindingsByKey.putIfAbsent(bindingKey, bindings)) != null)
{
bindings = newBindings;
}
}
if(_logger.isDebugEnabled())
{
_logger.debug("Exchange " + getName() + ": Binding " + queue.getName() +
" with binding key '" +bindingKey + "' and args: " + binding.getArguments());
}
_bindingHeaderMatchers.add(new HeadersBinding(binding));
bindings.add(binding);
}
@Override
protected void onBindingUpdated(final BindingImpl binding, final Map<String, Object> oldArguments)
{
HeadersBinding headersBinding = new HeadersBinding(binding);
ListIterator<HeadersBinding> iter = _bindingHeaderMatchers.listIterator();
while(iter.hasNext())
{
if(iter.next().equals(headersBinding))
{
iter.set(headersBinding);
}
}
}
protected void onUnbind(final BindingImpl binding)
{
assert binding != null;
CopyOnWriteArraySet<BindingImpl> bindings = _bindingsByKey.get(binding.getBindingKey());
if(bindings != null)
{
bindings.remove(binding);
}
boolean removedBinding = _bindingHeaderMatchers.remove(new HeadersBinding(binding));
if(_logger.isDebugEnabled())
{
_logger.debug("Removing Binding: " + removedBinding);
}
}
}