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root/i-scream/projects/cms/source/server/uk/org/iscream/cms/server/core/ConfigurationManagerServant.java
Revision: 1.11
Committed: Thu Mar 1 19:42:20 2001 UTC (23 years, 2 months ago) by ajm
Branch: MAIN
Changes since 1.10: +21 -17 lines
Log Message:
now handles nulls better.
also prints group debugging information.

File Contents

# User Rev Content
1 ajm 1.3 //---PACKAGE DECLARATION---
2 ajm 1.5 package uk.ac.ukc.iscream.core;
3 ajm 1.3
4     //---IMPORTS---
5 ajm 1.6 import uk.ac.ukc.iscream.util.*;
6 tdb 1.7 import uk.ac.ukc.iscream.componentmanager.*;
7 ajm 1.3 import java.util.*;
8     import java.io.*;
9    
10     /**
11     * This class is essentially a Configuration factory.
12     * This class implements the Configurator IDL and allows
13     * other classes in the system ot obtain their Configuration
14     *
15     * On construction it requires a reference to the RootPOA
16     * to allow it to create Configuration objects to be
17     * returned.
18     *
19     * It also relies on the System.properties to set internal values.
20     *
21 ajm 1.6 * ###
22     * A point to note is that this class does NOT yet manage
23     * created configurations which may cause memory problems!
24     * ###
25     *
26 ajm 1.9 * @author $Author: ajm4 $
27 ajm 1.11 * @version $Id: ConfigurationManagerServant.java,v 1.10 2001/03/01 19:36:08 ajm4 Exp $
28 ajm 1.3 */
29     class ConfigurationManagerServant extends ConfigurationManagerPOA {
30    
31     //---FINAL ATTRIBUTES---
32    
33     /**
34     * The current CVS revision of this class
35     */
36 ajm 1.11 public final String REVISION = "$Revision: 1.10 $";
37 ajm 1.3
38     //---STATIC METHODS---
39    
40     //---CONSTRUCTORS---
41    
42     /**
43     * Creates a new ConfiguratorServant
44     * This class uses the System.properties to set internal values
45     */
46 ajm 1.6 ConfigurationManagerServant() {
47 ajm 1.3 // assign some local variables
48     _configPath = System.getProperty("uk.ac.ukc.iscream.ConfigurationLocation");
49     _systemConfigFile = System.getProperty("uk.ac.ukc.iscream.SystemConfigurationFile");
50    
51     // load the system config
52     loadSystemConfig();
53    
54     // log our status
55 ajm 1.6 _logger.write(toString(), Logger.SYSINIT, "started");
56     _logger.write(toString(), Logger.SYSMSG, "configuration location - " + _configPath);
57     _logger.write(toString(), Logger.SYSMSG, "system configuration file - " + _systemConfigFile);
58 ajm 1.3 }
59    
60     //---PUBLIC METHODS---
61    
62     /**
63     * Returns a Configuration object which contains
64     * the configuration data requested by the calling
65     * object.
66     *
67     * This method will look in the systemConfig file
68     * for an entry for this "source", if there is no
69     * entry it returns a refernce to the system
70     * config. If there are any errors in reading the
71     * configuration, it returns null, the caller is
72     * expected to be able to handle this.
73     *
74     * This method also checks to see if the system.conf
75     * file has been updated and reloads its reference if
76     * needed.
77     *
78     * @param source the configuration required
79     * @return the Configuration
80     */
81     public Configuration getConfiguration(String source) {
82 ajm 1.6 _logger.write(toString(), Logger.SYSMSG, "got request for " + source);
83 ajm 1.8
84 ajm 1.3
85     // check to see if we need to reload the system config
86     // because it has changed
87     if (isModified(_systemConfig.getFileList(), _systemConfig.getLastModified())) {
88 ajm 1.6 _logger.write(toString(), Logger.SYSMSG, "system config changed");
89 ajm 1.3 loadSystemConfig();
90     }
91    
92 ajm 1.8 // search config for group membership
93     LinkedList groups = getGroupMembership(source);
94 ajm 1.3
95 ajm 1.8 // add the hosts individual config to the start of the list
96     groups.addFirst(source);
97 ajm 1.3
98 ajm 1.8 Iterator i = groups.iterator();
99     String fileList = "";
100     while (i.hasNext()) {
101     String groupName = (String) i.next();
102 ajm 1.11 _logger.write(toString(), Logger.DEBUG, "looking for config entry for - " + groupName);
103 ajm 1.8 // we look for this entry in the systemConfig
104     String configFile = _systemConfig.getProperty("config." + groupName);
105 ajm 1.11 // if there is a config entry then
106     if (configFile != null) {
107     _logger.write(toString(), Logger.DEBUG, "looking for config tree in - " + configFile);
108    
109     // get the file list of includes etc + the system config
110     String groupFileList = null;
111     try {
112     groupFileList = getIncludedFiles(configFile, "") + ";";
113     } catch (Exception e) {
114     // not sure what to do here
115     // so we just log the error
116     _logger.write(toString(), Logger.ERROR, "ERROR - " + e);
117     }
118     if (groupFileList != null) {
119     fileList += groupFileList;
120     }
121     } else {
122     _logger.write(toString(), Logger.DEBUG, "no config entry for - " + groupName);
123 ajm 1.3 }
124 ajm 1.8 // add the system config as the final check
125     fileList += _systemConfigFile + ";";
126     _logger.write(toString(), Logger.DEBUG, "config tree - " + fileList);
127    
128     // build the configuration
129     Configuration config = buildConfiguration(fileList);
130 ajm 1.3
131     // if this is null at this point, then there will have been an error
132     return config;
133     }
134    
135    
136     /**
137     * When passed a file list and a current value for the lastModified
138     * of the current configuration, this method compares the value
139     * to the actual value of the configuration files to determine
140     * whether or not the configuration has been modified.
141     *
142     * @param fileList a list of files that the caller uses for configuration
143     * @param lastModified the last modified date of the callers configuration
144     *
145     * @return whether or not the configuration has been modified
146     */
147     public boolean isModified(String fileList, long lastModified) {
148     StringTokenizer st = new StringTokenizer(fileList, ";");
149     long newLastModified;
150     File currentFile;
151     while (st.hasMoreTokens()) {
152     currentFile = new File(_configPath, st.nextToken());
153     newLastModified = currentFile.lastModified();
154     if (newLastModified > lastModified) {
155     return true;
156     }
157     }
158     return false;
159     }
160 ajm 1.6
161 ajm 1.3 /**
162     * Overrides the {@link java.lang.Object#toString() Object.toString()}
163     * method to provide clean logging (every class should have this).
164     *
165 ajm 1.6 * This uses the uk.ac.ukc.iscream.util.FormatName class
166     * to format the toString()
167     *
168 ajm 1.3 * @return the name of this class and its CVS revision
169     */
170     public String toString() {
171 ajm 1.6 return FormatName.getName(
172     _name,
173     getClass().getName(),
174     REVISION);
175 ajm 1.3 }
176    
177     //---PRIVATE METHODS---
178    
179     /**
180     * This is a recursive function private to this class.
181     * It constructs a hierarchy of files as a ";" serperated
182     * string which can be used to read in the configuration.
183     * This function calls itself.
184     *
185     * @param currentFile the current file to be processed
186 ajm 1.4 * @param readFiles used for recursion purposes only, these are the files it has read so far
187     *
188 ajm 1.3 * @return the current list that has been constructed
189     *
190     * @throws IOException if there is trouble reading the file
191     * @throws FileNotFoundException is there is trouble finding the file
192 ajm 1.4 * @throws CircularIncludeException this is if a circular include is detected
193 ajm 1.3 */
194 ajm 1.4 private String getIncludedFiles(String currentFile, String readFiles) throws IOException, FileNotFoundException, Exception {
195    
196     // check for circular include here
197     if (hasDuplicate(currentFile, readFiles) || currentFile.equals(_systemConfigFile)) {
198     throw new CircularIncludeException(currentFile + " is included more than once");
199     }
200    
201     // if there wasn't, we're gonna use this file, so make a note of it as read
202     // (note the use of the ";", this is for the hasDuplicate, function)
203     readFiles = readFiles + currentFile + ";";
204    
205 ajm 1.3 Properties properties = new Properties();
206     properties.load(new FileInputStream(new File(_configPath, currentFile)));
207 ajm 1.4
208     // get the include property
209 ajm 1.3 String includes = properties.getProperty("include");
210 ajm 1.4
211     // if we're the last file with no includes, return our name
212 ajm 1.3 if (includes == null) {
213     return currentFile;
214 ajm 1.4
215     // otherwise, recurse over our includes
216 ajm 1.3 } else {
217     StringTokenizer st = new StringTokenizer(includes, ";");
218     String returnList= "";
219     while (st.hasMoreTokens()) {
220 ajm 1.4 returnList = getIncludedFiles(st.nextToken(), readFiles) + ";" + returnList;
221 ajm 1.3 }
222 ajm 1.4
223 ajm 1.3 return returnList + currentFile;
224     }
225     }
226    
227     /**
228 ajm 1.4 * This simple method checks to see if a given
229     * file exists in the given list.
230     *
231     * @param file the file to check the list for
232     * @param fileList the list to check
233     *
234     * @return if the given file appeard in the list
235     */
236     private boolean hasDuplicate(String file, String fileList) {
237     StringTokenizer st = new StringTokenizer(fileList, ";");
238     while (st.hasMoreTokens()) {
239     if (file.equals(st.nextToken())) {
240     return true;
241     }
242     }
243     return false;
244     }
245    
246     /**
247 ajm 1.3 * Opens and loads the system configuration into the
248     * local reference _systemConfig
249     */
250     private void loadSystemConfig() {
251 ajm 1.6 _logger.write(this.toString(), Logger.SYSMSG, "reloading " + _systemConfigFile);
252 ajm 1.3 // get a reference to the system config and store it
253     try {
254     // create the properties for the configuration
255     File systemConfigFile = new File(_configPath, _systemConfigFile);
256 ajm 1.8 _systemConfigHolder = new Properties();
257     _systemConfigHolder.load(new FileInputStream(systemConfigFile));
258    
259 ajm 1.3 // create the servant
260 ajm 1.8 ConfigurationServant ref = new ConfigurationServant(_systemConfigHolder, _systemConfigFile, systemConfigFile.lastModified());
261 ajm 1.6 org.omg.CORBA.Object objRef = _refman.getRootPOA().servant_to_reference(ref);
262 ajm 1.3
263     // narrow it to a Configuration
264     _systemConfig = ConfigurationHelper.narrow(objRef);
265    
266     } catch (Exception e) {
267 ajm 1.6 _logger.write(toString(), Logger.FATAL, "ERROR: " + e.getMessage());
268 ajm 1.3 }
269     }
270    
271 ajm 1.8 /**
272     * Parses the system configuration file
273     * for group membership entries.
274     *
275     * It looks for all entries of group.<name>
276     * which contain the given source name
277     *
278     * @param source the source to find membership for
279     *
280     * @return the list of groups that this source is a member of
281     */
282     private LinkedList getGroupMembership(String source) {
283     LinkedList groupMembership = new LinkedList();
284     Iterator i = new TreeSet(_systemConfigHolder.keySet()).iterator();
285     while(i.hasNext()) {
286     String key = (String) i.next();
287     if (key.startsWith("group.")) {
288     String group = _systemConfig.getProperty(key);
289     if (group.indexOf(source) != -1) {
290     groupMembership.add(key.substring(6));
291     }
292     }
293     }
294     return groupMembership;
295     }
296    
297     /**
298     * Build the properties as a Configuration to be
299     * returned to the caller
300     *
301     * @param fileList the list of files to build the configuration from
302     *
303     * @return the built Configuration
304     */
305     private Configuration buildConfiguration(String fileList) {
306     Configuration config = null;
307    
308     // if there is an entry
309 ajm 1.10 if (!fileList.equals("")) {
310 ajm 1.8 try {
311    
312     // build the properites here from the filelist....
313     StringTokenizer st = new StringTokenizer(fileList, ";");
314    
315     // some holders for variables
316     File currentFile;
317     long lastModified, newLastModified;
318     Properties properties, prevProperties;
319    
320     // the root of all configurations will be the system config
321     // so we need to open the properties of that
322     Properties defaultProperties = new Properties();
323     currentFile = new File(_configPath, _systemConfigFile);
324     lastModified = currentFile.lastModified();
325     defaultProperties.load(new FileInputStream(currentFile));
326    
327     // This loop then iterates over the file list
328     // creates the properties to be passed to the
329     // Configuration constructor
330     do {
331     properties = new Properties(defaultProperties);
332     currentFile = new File(_configPath, st.nextToken());
333     newLastModified = currentFile.lastModified();
334     if (newLastModified > lastModified) {
335     lastModified = newLastModified;
336     }
337     properties.load(new FileInputStream(currentFile));
338     defaultProperties = properties;
339     } while (st.hasMoreTokens());
340    
341     // this creates the configuration, all nice, ready to be returned
342     ConfigurationServant ref = new ConfigurationServant(properties, fileList, lastModified);
343     org.omg.CORBA.Object objRef = _refman.getRootPOA().servant_to_reference(ref);
344     config = ConfigurationHelper.narrow(objRef);
345    
346     } catch (Exception e) {
347     // not sure what to do here
348     // so we just log the error
349 ajm 1.10 _logger.write(toString(), Logger.ERROR, "ERROR - " + e);
350 ajm 1.8 }
351    
352     // if there isn't an entry for the requested config
353     } else {
354     _logger.write(toString(), Logger.DEBUG, "no configured config, returning " + _systemConfigFile);
355     config = _systemConfig;
356     }
357     return config;
358     }
359    
360 ajm 1.3 //---ACCESSOR/MUTATOR METHODS---
361    
362     //---ATTRIBUTES---
363    
364     /**
365 ajm 1.6 * This is the friendly identifier of the
366     * component this class is running in.
367     * eg, a Filter may be called "filter1",
368     * If this class does not have an owning
369     * component, a name from the configuration
370     * can be placed here. This name could also
371     * be changed to null for utility classes.
372     */
373     private String _name = Core.NAME;
374    
375     /**
376     * This holds a reference to the
377     * system logger that is being used.
378 ajm 1.3 */
379 ajm 1.6 private Logger _logger = ReferenceManager.getInstance().getLogger();
380 ajm 1.3
381     /**
382 ajm 1.6 * A reference to the reference manager in use
383 ajm 1.3 */
384 ajm 1.6 private ReferenceManager _refman = ReferenceManager.getInstance();
385 ajm 1.3
386     /**
387     * The root path to all configurations
388     */
389     private String _configPath;
390    
391     /**
392     * The name of the file that contains the system configuration
393     */
394     private String _systemConfigFile;
395    
396     /**
397     * An instance of the system config
398     */
399     private Configuration _systemConfig;
400 ajm 1.8
401     /**
402     * The system config file represented by a
403     * properties object.
404     */
405     private Properties _systemConfigHolder;
406 ajm 1.3
407     //---STATIC ATTRIBUTES---
408    
409     }