2 * Copyright 2005-2011 the original author or authors.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package org.wamblee.xmlrouter.impl;
18 import java.util.ArrayList;
19 import java.util.Collection;
20 import java.util.HashSet;
21 import java.util.LinkedHashMap;
22 import java.util.List;
25 import java.util.concurrent.atomic.AtomicLong;
26 import java.util.logging.Level;
27 import java.util.logging.Logger;
29 import javax.xml.transform.dom.DOMSource;
31 import org.wamblee.general.Clock;
32 import org.wamblee.general.Pair;
33 import org.wamblee.xml.XMLDocument;
34 import org.wamblee.xmlrouter.common.Id;
35 import org.wamblee.xmlrouter.config.DocumentType;
36 import org.wamblee.xmlrouter.config.Filter;
37 import org.wamblee.xmlrouter.config.Transformation;
38 import org.wamblee.xmlrouter.listener.EventInfo;
39 import org.wamblee.xmlrouter.listener.EventListener;
40 import org.wamblee.xmlrouter.publish.Gateway;
41 import org.wamblee.xmlrouter.subscribe.Destination;
42 import org.wamblee.xmlrouter.subscribe.DestinationRegistry;
47 * @author Erik Brakkee
50 public class XMLRouter implements Gateway, DestinationRegistry {
52 private static final Logger LOGGER = Logger.getLogger(XMLRouter.class
55 private AtomicLong sequenceNumbers;
56 private EventListener listener;
58 private AtomicLong nextEventId;
60 private XMLRouterConfiguration config;
62 private Map<Id<Destination>, Destination> destinations;
64 public XMLRouter(Clock aClock, XMLRouterConfiguration aConfig,
65 EventListener aListener) {
66 sequenceNumbers = new AtomicLong(1);
69 nextEventId = new AtomicLong(clock.currentTimeMillis());
71 destinations = new LinkedHashMap<Id<Destination>, Destination>();
75 public void publish(String aSource, DOMSource aEvent) {
76 long time = clock.currentTimeMillis();
78 Pair<ExtendedRouterConfig, TransformationPaths> snapshotconfig = config
81 Id<DOMSource> id = new Id<DOMSource>(nextEventId.getAndIncrement() + "");
82 List<String> types = determineDocumentTypes(snapshotconfig.getFirst()
83 .documentTypeConfig().values(), aEvent);
84 EventInfo info = new EventInfo(time, aSource, id, types, aEvent);
86 boolean delivered = false;
89 List<String> filteredInputTypes = determineFilteredInputTypes(
90 snapshotconfig.getFirst().filterConfig().values(), types,
92 if (filteredInputTypes.isEmpty()) {
93 if (LOGGER.isLoggable(Level.FINE)) {
94 String doc = new XMLDocument(aEvent).print(true);
98 "Event ''{0}'' from source ''{1}'' removed because of filters.",
99 new Object[] { doc, aSource });
103 // get the reachable target types through transformations.
105 // It is possible that a given event belongs to multiple input
107 // This is however certainly not the main case.
109 for (String inputType : filteredInputTypes) {
110 boolean result = deliverEvent(snapshotconfig.getFirst()
111 .filterConfig().values(), snapshotconfig.getSecond(), info,
113 delivered = delivered || result;
117 destinationNotFound(aSource, aEvent);
118 listener.notDelivered(info);
123 private boolean deliverEvent(Collection<Filter> aFilters,
124 TransformationPaths aTransformations, EventInfo aInfo, String aInputType) {
126 boolean delivered = false;
127 Set<String> possibleTargetTypes = new HashSet<String>();
128 possibleTargetTypes.addAll(aTransformations
129 .getPossibleTargetTypes(aInputType));
131 // ask each destination what target types, if any they want to have.
132 for (Map.Entry<Id<Destination>, Destination> entry : destinations
134 Id<Destination> destinationId = entry.getKey();
135 Destination destination = entry.getValue();
136 Collection<String> requested = destination
137 .chooseFromTargetTypes(possibleTargetTypes);
138 if (!requested.isEmpty()) {
139 // Deliver to the destination.
140 for (String targetType : requested) {
141 TransformationPath path = aTransformations.getPath(
142 aInputType, targetType);
143 List<Transformation> ts = path.getTransformations();
145 boolean allowed = true;
146 DOMSource transformed = aInfo.getEvent();
147 while (i < ts.size() && allowed && transformed != null) {
148 Transformation t = ts.get(i);
149 DOMSource orig = transformed;
150 transformed = t.transform(transformed);
151 if (transformed == null) {
152 transformationReturnedNull(aInfo.getSource(),
153 aInfo.getEvent(), aInputType, t, orig);
156 if (!isAllowedByFilters(aFilters, t.getToType(),
162 if (allowed && transformed != null) {
163 // all transformations done and all filters still
165 boolean result = destination.receive(transformed);
166 listener.delivered(aInfo, ts, destinationId.getId(),
168 delivered = delivered || result;
177 private List<String> determineFilteredInputTypes(
178 Collection<Filter> aFilters, List<String> aTypes, DOMSource aEvent) {
180 // apply filters to the input
181 List<String> filteredTypes = new ArrayList<String>();
182 for (String type : aTypes) {
183 boolean allowed = isAllowedByFilters(aFilters, type, aEvent);
185 filteredTypes.add(type);
188 return filteredTypes;
191 private boolean isAllowedByFilters(Collection<Filter> aFilters,
192 String aType, DOMSource aEvent) {
193 boolean allowed = true;
194 for (Filter filter : aFilters) {
195 if (!filter.isAllowed(aType, aEvent)) {
202 private List<String> determineDocumentTypes(
203 Collection<DocumentType> aTypes, DOMSource aEvent) {
204 List<String> res = new ArrayList<String>();
205 for (DocumentType type : aTypes) {
206 if (type.isInstance(aEvent)) {
207 res.add(type.getName());
213 private String eventToString(String aSource, DOMSource aEvent) {
214 return "source '" + aSource + "': Event: '" +
215 new XMLDocument(aEvent).print(true) + "'";
218 private void transformationReturnedNull(String aSource, DOMSource aEvent,
219 String aInputType, Transformation aT, DOMSource aTransformed) {
220 LOGGER.log(Level.WARNING, "Transformation returned null for event " +
221 eventToString(aSource, aEvent) + " inputType '" + aInputType +
222 "', transformation '" + aT + "' document to transform " +
223 new XMLDocument(aTransformed).print(true));
226 private void destinationNotFound(String aSource, DOMSource aEvent) {
227 LOGGER.log(Level.WARNING, "No destination found for event: " +
228 eventToString(aSource, aEvent));
232 public Id<Destination> registerDestination(Destination aDestination) {
233 notNull("destination", aDestination);
234 long seqno = sequenceNumbers.getAndIncrement();
235 Id<Destination> id = new Id<Destination>(seqno + "");
236 destinations.put(id, new RobustDestination(id, aDestination));
241 public void unregisterDestination(Id<Destination> aId) {
242 destinations.remove(aId);
245 private void notNull(String aName, Object aValue) {
246 if (aValue == null) {
247 throw new IllegalArgumentException("Parameter '" + aName +
248 "' may not be null");