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.xml.XMLDocument;
33 import org.wamblee.xmlrouter.common.Id;
34 import org.wamblee.xmlrouter.config.DocumentType;
35 import org.wamblee.xmlrouter.config.Filter;
36 import org.wamblee.xmlrouter.config.Transformation;
37 import org.wamblee.xmlrouter.listener.EventInfo;
38 import org.wamblee.xmlrouter.listener.EventListener;
39 import org.wamblee.xmlrouter.publish.Gateway;
40 import org.wamblee.xmlrouter.subscribe.Destination;
41 import org.wamblee.xmlrouter.subscribe.DestinationRegistry;
43 // TODO check intermediate types during transformation based on filters.
48 * @author Erik Brakkee
51 public class XMLRouter implements Gateway, DestinationRegistry {
53 private static final Logger LOGGER = Logger.getLogger(XMLRouter.class
56 private AtomicLong sequenceNumbers;
57 private EventListener listener;
59 private AtomicLong nextEventId;
61 private XMLRouterConfiguration config;
63 private Map<Id<Destination>, Destination> destinations;
65 public XMLRouter(Clock aClock, XMLRouterConfiguration aConfig,
66 EventListener aListener) {
67 sequenceNumbers = new AtomicLong(1);
70 nextEventId = new AtomicLong(clock.currentTimeMillis());
72 destinations = new LinkedHashMap<Id<Destination>, Destination>();
76 public void publish(String aSource, DOMSource aEvent) {
77 config.startPublishEvent();
79 publishImpl(aSource, aEvent);
81 config.endPublishEvent();
85 private void publishImpl(String aSource, DOMSource aEvent) {
86 long time = clock.currentTimeMillis();
88 Id<DOMSource> id = new Id<DOMSource>(nextEventId.getAndIncrement() + "");
89 List<String> types = determineDocumentTypes(aEvent);
90 EventInfo info = new EventInfo(time, aSource, id, types, aEvent);
92 boolean delivered = false;
95 List<String> filteredInputTypes = determineFilteredInputTypes(
97 if (filteredInputTypes.isEmpty()) {
98 if (LOGGER.isLoggable(Level.FINE)) {
99 String doc = new XMLDocument(aEvent).print(true);
103 "Event ''0}'' from source {1} removed because of filters.",
104 new Object[] { doc, aSource });
108 // get the reachable target types through transformations.
110 // It is possible that a given event belongs to multiple input
112 // This is however certainly not the main case.
114 for (String inputType : filteredInputTypes) {
115 boolean result = deliverEvent(info, inputType);
116 delivered = delivered || result;
120 destinationNotFound(aSource, aEvent);
121 listener.notDelivered(info);
126 private boolean deliverEvent(EventInfo aInfo, String aInputType) {
128 boolean delivered = false;
129 Set<String> possibleTargetTypes = new HashSet<String>();
130 possibleTargetTypes.addAll(config.getTransformations()
131 .getPossibleTargetTypes(aInputType));
133 // ask each destination what target types, if any they want to have.
134 for (Map.Entry<Id<Destination>, Destination> entry : destinations
136 Id<Destination> destinationId = entry.getKey();
137 Destination destination = entry.getValue();
138 Collection<String> requested = destination
139 .chooseFromTargetTypes(possibleTargetTypes);
140 if (!requested.isEmpty()) {
141 // Deliver to the destination.
142 for (String targetType : requested) {
143 TransformationPath path = config.getTransformations()
144 .getPath(aInputType, targetType);
145 List<Transformation> ts = path.getTransformations();
147 boolean allowed = true;
148 DOMSource transformed = aInfo.getEvent();
149 while (i < ts.size() && allowed && transformed != null) {
150 Transformation t = ts.get(i);
151 DOMSource orig = transformed;
152 transformed = t.transform(transformed);
153 if (transformed == null) {
154 transformationReturnedNull(aInfo.getSource(),
155 aInfo.getEvent(), aInputType, t, orig);
158 if (!isAllowedByFilters(t.getToType(), transformed)) {
163 if (allowed && transformed != null) {
164 // all transformations done and all filters still
166 boolean result = destination.receive(transformed);
167 listener.delivered(aInfo, ts, destinationId.getId(),
169 delivered = delivered || result;
178 private List<String> determineFilteredInputTypes(List<String> aTypes,
181 // apply filters to the input
182 List<String> filteredTypes = new ArrayList<String>();
183 for (String type : aTypes) {
184 boolean allowed = isAllowedByFilters(type, aEvent);
186 filteredTypes.add(type);
189 return filteredTypes;
192 private boolean isAllowedByFilters(String aType, DOMSource aEvent) {
193 boolean allowed = true;
194 for (Filter filter : config.getRouterConfig().filterConfig().values()) {
195 if (!filter.isAllowed(aType, aEvent)) {
202 private List<String> determineDocumentTypes(DOMSource aEvent) {
203 List<String> res = new ArrayList<String>();
204 for (DocumentType type : config.getRouterConfig().documentTypeConfig()
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");