001 /*
002 // This software is subject to the terms of the Common Public License
003 // Agreement, available at the following URL:
004 // http://www.opensource.org/licenses/cpl.html.
005 // Copyright (C) 2006-2008 Julian Hyde
006 // All Rights Reserved.
007 // You must accept the terms of that agreement to use this software.
008 */
009
010 package mondrian.xmla.impl;
011
012 import mondrian.olap.Util;
013 import mondrian.rolap.CacheControlImpl;
014 import mondrian.rolap.RolapSchema;
015 import mondrian.xmla.DataSourcesConfig;
016
017 import javax.servlet.ServletException;
018 import javax.servlet.http.HttpServletRequest;
019 import javax.servlet.http.HttpServletResponse;
020 import java.io.IOException;
021 import java.net.URL;
022 import java.util.HashMap;
023 import java.util.Iterator;
024 import java.util.Map;
025
026 /**
027 * Extends DefaultXmlaServlet to add dynamic datasource loading capability.
028 * Limitations : Catalog name should be unique across the datasources
029 *
030 * @author Thiyagu, Ajit
031 */
032 public class DynamicDatasourceXmlaServlet extends DefaultXmlaServlet {
033 protected URL dataSourcesConfigUrl;
034 protected String lastDataSourcesConfigString;
035
036 protected void doPost(
037 HttpServletRequest request,
038 HttpServletResponse response)
039 throws ServletException, IOException {
040 reloadDataSources();
041 super.doPost(request, response);
042 }
043
044 /**
045 * Checks for updates to datasources content, flushes obsolete catalogs
046 */
047 void reloadDataSources() {
048 try {
049 String dataSourcesConfigString = readDataSourcesContent(dataSourcesConfigUrl);
050 if (hasDataSourcesContentChanged(dataSourcesConfigString)) {
051 DataSourcesConfig.DataSources newDataSources =
052 parseDataSources(dataSourcesConfigString);
053 if (newDataSources != null) {
054 flushObsoleteCatalogs(newDataSources);
055 this.dataSources = newDataSources;
056 xmlaHandler = null;
057 lastDataSourcesConfigString = dataSourcesConfigString;
058 }
059 }
060 } catch (Exception e) {
061 throw Util.newError(e, "Failed to parse data sources config '" +
062 dataSourcesConfigUrl.toExternalForm() + "'");
063 }
064 }
065
066 protected boolean hasDataSourcesContentChanged
067 (String dataSourcesConfigString) {
068 return dataSourcesConfigString != null
069 && !dataSourcesConfigString.equals(this.lastDataSourcesConfigString);
070 }
071
072 /**
073 * Overides XmlaServlet.parseDataSourcesUrl to store dataSorucesConfigUrl,
074 * Datasoruces Configuration content
075 * @param dataSourcesConfigUrl
076 */
077 protected DataSourcesConfig.DataSources parseDataSourcesUrl
078 (URL dataSourcesConfigUrl) {
079 this.dataSourcesConfigUrl = dataSourcesConfigUrl;
080 try {
081 String dataSourcesConfigString = readDataSourcesContent(dataSourcesConfigUrl);
082 if (lastDataSourcesConfigString == null) {
083 // This is the first time we are reading any datasource config
084 this.lastDataSourcesConfigString = dataSourcesConfigString;
085 }
086 return parseDataSources(dataSourcesConfigString);
087 } catch (Exception e) {
088 throw Util.newError(e, "Failed to parse data sources config '" +
089 dataSourcesConfigUrl.toExternalForm() + "'");
090 }
091 }
092
093 void flushObsoleteCatalogs(DataSourcesConfig.DataSources newDataSources) {
094 Map<String, DataSourcesConfig.Catalog> newDatasourceCatalogs =
095 createCatalogMap(newDataSources);
096
097 for (DataSourcesConfig.DataSource oldDataSource : dataSources.dataSources) {
098 for (DataSourcesConfig.Catalog oldCatalog : oldDataSource.catalogs.catalogs) {
099 DataSourcesConfig.Catalog newCatalog =
100 newDatasourceCatalogs.get(oldCatalog.name);
101 if (!(newCatalog != null &&
102 areCatalogsEqual(oldCatalog, newCatalog))) {
103 flushCatalog(oldCatalog.name);
104 }
105 }
106 }
107 }
108
109 private Map<String, DataSourcesConfig.Catalog> createCatalogMap
110 (DataSourcesConfig.DataSources newDataSources) {
111 Map<String, DataSourcesConfig.Catalog> newDatasourceCatalogNames =
112 new HashMap<String, DataSourcesConfig.Catalog>();
113 for (DataSourcesConfig.DataSource dataSource : newDataSources.dataSources) {
114 for (DataSourcesConfig.Catalog catalog : dataSource.catalogs.catalogs) {
115 newDatasourceCatalogNames.put(catalog.name, catalog);
116 }
117 }
118 return newDatasourceCatalogNames;
119 }
120
121 void flushCatalog(String catalogName) {
122 Iterator schemas = RolapSchema.getRolapSchemas();
123 while (schemas.hasNext()) {
124 RolapSchema curSchema = (RolapSchema) schemas.next();
125 if (curSchema.getName().equals(catalogName)) {
126 new CacheControlImpl().flushSchema(curSchema);
127 }
128 }
129 }
130
131 boolean areCatalogsEqual
132 (DataSourcesConfig.Catalog catalog1, DataSourcesConfig.Catalog catalog2) {
133
134 if ((catalog1.getDataSourceInfo() != null &&
135 catalog2.getDataSourceInfo() == null) ||
136 (catalog2.getDataSourceInfo() != null &&
137 catalog1.getDataSourceInfo() == null)) {
138 return false;
139 }
140
141 if ((catalog1.getDataSourceInfo() == null &&
142 catalog2.getDataSourceInfo() == null) ||
143 (catalog1.getDataSourceInfo().equals(catalog2.getDataSourceInfo()))) {
144
145 return (catalog1.name.equals(catalog2.name) &&
146 catalog1.definition.equals(catalog2.definition));
147 }
148 return false;
149 }
150 }
151
152 // End DynamicDatasourceXmlaServlet.java