001 /*
002 GRANITE DATA SERVICES
003 Copyright (C) 2011 GRANITE DATA SERVICES S.A.S.
004
005 This file is part of Granite Data Services.
006
007 Granite Data Services is free software; you can redistribute it and/or modify
008 it under the terms of the GNU Library General Public License as published by
009 the Free Software Foundation; either version 2 of the License, or (at your
010 option) any later version.
011
012 Granite Data Services is distributed in the hope that it will be useful, but
013 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
014 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
015 for more details.
016
017 You should have received a copy of the GNU Library General Public License
018 along with this library; if not, see <http://www.gnu.org/licenses/>.
019 */
020
021 package org.granite.tide.data;
022
023 import java.util.ArrayList;
024 import java.util.HashMap;
025 import java.util.List;
026 import java.util.Map;
027 import java.util.Map.Entry;
028
029 import javax.servlet.http.HttpSession;
030
031 import org.granite.clustering.GraniteDistributedData;
032 import org.granite.clustering.GraniteDistributedDataFactory;
033 import org.granite.context.GraniteContext;
034 import org.granite.logging.Logger;
035 import org.granite.messaging.webapp.HttpGraniteContext;
036
037 import flex.messaging.messages.AsyncMessage;
038
039
040 /**
041 * Base implementation for data update dispatchers.
042 * It should be built at beginning of each request during initialization of <code>DataContext</code>.
043 * The dispatch is a three step process :
044 *
045 * <ul>
046 * <li>Initialization in the constructor</li>
047 * <li><code>observe()</code> builds the server selector depending on the data that are processed</li>
048 * <li><code>publish()</code> handles the actual publishing</li>
049 * </ul>
050 *
051 * Actual implementations should only override <code>changeDataSelector</code> and <code>publishUpdate</code>/
052 *
053 * @see DataDispatcher
054 * @see DataContext
055 *
056 * @author William Drai
057 */
058 public abstract class AbstractDataDispatcher implements DataDispatcher {
059
060 private static final String TIDE_DATA_SELECTORS_KEY_PREFIX = "org.granite.tide.dataSelectors.";
061
062
063 private static final Logger log = Logger.getLogger(AbstractDataDispatcher.class);
064
065
066 protected boolean enabled;
067 protected String topicName = null;
068 protected DataTopicParams paramsProvider = null;
069 protected String sessionId = null;
070 protected String clientId = null;
071 protected String subscriptionId = null;
072
073
074 public AbstractDataDispatcher(String topicName, Class<? extends DataTopicParams> dataTopicParamsClass) {
075 this.topicName = topicName;
076
077 try {
078 paramsProvider = dataTopicParamsClass.newInstance();
079 }
080 catch (Exception e) {
081 log.error("Could not instantiate class " + dataTopicParamsClass, e);
082 }
083 }
084
085
086 public void observe() {
087 // Prepare the selector even if we are not yet subscribed
088 DataObserveParams params = null;
089 if (paramsProvider != null) {
090 // Collect selector parameters from component
091 params = new DataObserveParams();
092 paramsProvider.observes(params);
093 }
094
095
096 // Ensure that the current Gravity consumer listens about this data topic and params
097 GraniteContext graniteContext = GraniteContext.getCurrentInstance();
098 if (!(graniteContext instanceof HttpGraniteContext))
099 return;
100
101 GraniteDistributedData gdd = GraniteDistributedDataFactory.getInstance();
102 HttpSession session = ((HttpGraniteContext)graniteContext).getSession(false);
103
104 @SuppressWarnings("unchecked")
105 List<DataObserveParams> selectors = (List<DataObserveParams>)session.getAttribute(TIDE_DATA_SELECTORS_KEY_PREFIX + topicName);
106 if (selectors == null) {
107 selectors = new ArrayList<DataObserveParams>();
108 session.setAttribute(TIDE_DATA_SELECTORS_KEY_PREFIX + topicName, selectors);
109 }
110
111 boolean dataSelectorChanged = false;
112 String dataSelector = gdd.getDestinationSelector(topicName);
113 if (params != null) {
114 String newDataSelector = params.updateDataSelector(dataSelector, selectors);
115 dataSelectorChanged = !newDataSelector.equals(dataSelector);
116 if (dataSelectorChanged) {
117 gdd.setDestinationSelector(topicName, newDataSelector);
118 dataSelector = newDataSelector;
119 }
120 }
121
122 if (!enabled)
123 return;
124
125 if (dataSelectorChanged)
126 changeDataSelector(dataSelector);
127 }
128
129 protected abstract void changeDataSelector(String dataSelector);
130
131
132 public void publish(Object[][] dataUpdates) {
133 if (!enabled)
134 return;
135
136 try {
137 Map<Map<String, String>, List<Object>> updates = new HashMap<Map<String, String>, List<Object>>();
138 if (paramsProvider != null) {
139 for (Object[] dataUpdate : dataUpdates) {
140 DataPublishParams params = new DataPublishParams();
141 paramsProvider.publishes(params, dataUpdate[1]);
142
143 Map<String, String> headers = params.getHeaders();
144 List<Object> list = updates.get(headers);
145 if (list == null) {
146 list = new ArrayList<Object>();
147 updates.put(headers, list);
148 }
149 list.add(dataUpdate);
150 }
151 }
152
153 for (Entry<Map<String, String>, List<Object>> me : updates.entrySet()) {
154 Map<String, String> headers = new HashMap<String, String>(me.getKey());
155 headers.put(AsyncMessage.SUBTOPIC_HEADER, TIDE_DATA_SUBTOPIC);
156 headers.put(GDS_SESSION_ID, sessionId);
157 headers.put(TIDE_DATA_TYPE_KEY, TIDE_DATA_TYPE_VALUE);
158 publishUpdate(headers, me.getValue().toArray());
159 }
160 }
161 catch (Exception e) {
162 log.error(e, "Could not publish data update on topic %s", topicName);
163 }
164 }
165
166 protected abstract void publishUpdate(Map<String, String> params, Object body);
167 }