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root/i-scream/projects/cms/source/server/uk/org/iscream/cms/server/core/ConfigurationManagerServant.java
Revision: 1.10
Committed: Thu Mar 1 19:36:08 2001 UTC (23 years, 2 months ago) by ajm
Branch: MAIN
Changes since 1.9: +8 -4 lines
Log Message:
fixed null pointer problems.
now prints nicer error messages in the log.

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     * @version $Id: ConfigurationManagerServant.java,v 1.8 2001/03/01 19:18:38 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 1.9 public final String REVISION = "$Revision: 1.8 $";
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    
103     // we look for this entry in the systemConfig
104     String configFile = _systemConfig.getProperty("config." + groupName);
105     _logger.write(toString(), Logger.DEBUG, "looking for config tree in - " + configFile);
106 ajm 1.3
107 ajm 1.8 // get the file list of includes etc + the system config
108 ajm 1.10 String groupFileList = null;
109 ajm 1.8 try {
110 ajm 1.10 groupFileList = getIncludedFiles(configFile, "") + ";";
111 ajm 1.3 } catch (Exception e) {
112     // not sure what to do here
113 ajm 1.6 // so we just log the error
114 ajm 1.10 _logger.write(toString(), Logger.ERROR, "ERROR - " + e);
115     }
116     if (groupFileList != null) {
117     fileList += groupFileList;
118 ajm 1.3 }
119     }
120 ajm 1.8 // add the system config as the final check
121     fileList += _systemConfigFile + ";";
122     _logger.write(toString(), Logger.DEBUG, "config tree - " + fileList);
123    
124     // build the configuration
125     Configuration config = buildConfiguration(fileList);
126 ajm 1.3
127     // if this is null at this point, then there will have been an error
128     return config;
129     }
130    
131    
132     /**
133     * When passed a file list and a current value for the lastModified
134     * of the current configuration, this method compares the value
135     * to the actual value of the configuration files to determine
136     * whether or not the configuration has been modified.
137     *
138     * @param fileList a list of files that the caller uses for configuration
139     * @param lastModified the last modified date of the callers configuration
140     *
141     * @return whether or not the configuration has been modified
142     */
143     public boolean isModified(String fileList, long lastModified) {
144     StringTokenizer st = new StringTokenizer(fileList, ";");
145     long newLastModified;
146     File currentFile;
147     while (st.hasMoreTokens()) {
148     currentFile = new File(_configPath, st.nextToken());
149     newLastModified = currentFile.lastModified();
150     if (newLastModified > lastModified) {
151     return true;
152     }
153     }
154     return false;
155     }
156 ajm 1.6
157 ajm 1.3 /**
158     * Overrides the {@link java.lang.Object#toString() Object.toString()}
159     * method to provide clean logging (every class should have this).
160     *
161 ajm 1.6 * This uses the uk.ac.ukc.iscream.util.FormatName class
162     * to format the toString()
163     *
164 ajm 1.3 * @return the name of this class and its CVS revision
165     */
166     public String toString() {
167 ajm 1.6 return FormatName.getName(
168     _name,
169     getClass().getName(),
170     REVISION);
171 ajm 1.3 }
172    
173     //---PRIVATE METHODS---
174    
175     /**
176     * This is a recursive function private to this class.
177     * It constructs a hierarchy of files as a ";" serperated
178     * string which can be used to read in the configuration.
179     * This function calls itself.
180     *
181     * @param currentFile the current file to be processed
182 ajm 1.4 * @param readFiles used for recursion purposes only, these are the files it has read so far
183     *
184 ajm 1.3 * @return the current list that has been constructed
185     *
186     * @throws IOException if there is trouble reading the file
187     * @throws FileNotFoundException is there is trouble finding the file
188 ajm 1.4 * @throws CircularIncludeException this is if a circular include is detected
189 ajm 1.3 */
190 ajm 1.4 private String getIncludedFiles(String currentFile, String readFiles) throws IOException, FileNotFoundException, Exception {
191    
192     // check for circular include here
193     if (hasDuplicate(currentFile, readFiles) || currentFile.equals(_systemConfigFile)) {
194     throw new CircularIncludeException(currentFile + " is included more than once");
195     }
196    
197     // if there wasn't, we're gonna use this file, so make a note of it as read
198     // (note the use of the ";", this is for the hasDuplicate, function)
199     readFiles = readFiles + currentFile + ";";
200    
201 ajm 1.3 Properties properties = new Properties();
202     properties.load(new FileInputStream(new File(_configPath, currentFile)));
203 ajm 1.4
204     // get the include property
205 ajm 1.3 String includes = properties.getProperty("include");
206 ajm 1.4
207     // if we're the last file with no includes, return our name
208 ajm 1.3 if (includes == null) {
209     return currentFile;
210 ajm 1.4
211     // otherwise, recurse over our includes
212 ajm 1.3 } else {
213     StringTokenizer st = new StringTokenizer(includes, ";");
214     String returnList= "";
215     while (st.hasMoreTokens()) {
216 ajm 1.4 returnList = getIncludedFiles(st.nextToken(), readFiles) + ";" + returnList;
217 ajm 1.3 }
218 ajm 1.4
219 ajm 1.3 return returnList + currentFile;
220     }
221     }
222    
223     /**
224 ajm 1.4 * This simple method checks to see if a given
225     * file exists in the given list.
226     *
227     * @param file the file to check the list for
228     * @param fileList the list to check
229     *
230     * @return if the given file appeard in the list
231     */
232     private boolean hasDuplicate(String file, String fileList) {
233     StringTokenizer st = new StringTokenizer(fileList, ";");
234     while (st.hasMoreTokens()) {
235     if (file.equals(st.nextToken())) {
236     return true;
237     }
238     }
239     return false;
240     }
241    
242     /**
243 ajm 1.3 * Opens and loads the system configuration into the
244     * local reference _systemConfig
245     */
246     private void loadSystemConfig() {
247 ajm 1.6 _logger.write(this.toString(), Logger.SYSMSG, "reloading " + _systemConfigFile);
248 ajm 1.3 // get a reference to the system config and store it
249     try {
250     // create the properties for the configuration
251     File systemConfigFile = new File(_configPath, _systemConfigFile);
252 ajm 1.8 _systemConfigHolder = new Properties();
253     _systemConfigHolder.load(new FileInputStream(systemConfigFile));
254    
255 ajm 1.3 // create the servant
256 ajm 1.8 ConfigurationServant ref = new ConfigurationServant(_systemConfigHolder, _systemConfigFile, systemConfigFile.lastModified());
257 ajm 1.6 org.omg.CORBA.Object objRef = _refman.getRootPOA().servant_to_reference(ref);
258 ajm 1.3
259     // narrow it to a Configuration
260     _systemConfig = ConfigurationHelper.narrow(objRef);
261    
262     } catch (Exception e) {
263 ajm 1.6 _logger.write(toString(), Logger.FATAL, "ERROR: " + e.getMessage());
264 ajm 1.3 }
265     }
266    
267 ajm 1.8 /**
268     * Parses the system configuration file
269     * for group membership entries.
270     *
271     * It looks for all entries of group.<name>
272     * which contain the given source name
273     *
274     * @param source the source to find membership for
275     *
276     * @return the list of groups that this source is a member of
277     */
278     private LinkedList getGroupMembership(String source) {
279     LinkedList groupMembership = new LinkedList();
280     Iterator i = new TreeSet(_systemConfigHolder.keySet()).iterator();
281     while(i.hasNext()) {
282     String key = (String) i.next();
283     if (key.startsWith("group.")) {
284     String group = _systemConfig.getProperty(key);
285     if (group.indexOf(source) != -1) {
286     groupMembership.add(key.substring(6));
287     }
288     }
289     }
290     return groupMembership;
291     }
292    
293     /**
294     * Build the properties as a Configuration to be
295     * returned to the caller
296     *
297     * @param fileList the list of files to build the configuration from
298     *
299     * @return the built Configuration
300     */
301     private Configuration buildConfiguration(String fileList) {
302     Configuration config = null;
303    
304     // if there is an entry
305 ajm 1.10 if (!fileList.equals("")) {
306 ajm 1.8 try {
307    
308     // build the properites here from the filelist....
309     StringTokenizer st = new StringTokenizer(fileList, ";");
310    
311     // some holders for variables
312     File currentFile;
313     long lastModified, newLastModified;
314     Properties properties, prevProperties;
315    
316     // the root of all configurations will be the system config
317     // so we need to open the properties of that
318     Properties defaultProperties = new Properties();
319     currentFile = new File(_configPath, _systemConfigFile);
320     lastModified = currentFile.lastModified();
321     defaultProperties.load(new FileInputStream(currentFile));
322    
323     // This loop then iterates over the file list
324     // creates the properties to be passed to the
325     // Configuration constructor
326     do {
327     properties = new Properties(defaultProperties);
328     currentFile = new File(_configPath, st.nextToken());
329     newLastModified = currentFile.lastModified();
330     if (newLastModified > lastModified) {
331     lastModified = newLastModified;
332     }
333     properties.load(new FileInputStream(currentFile));
334     defaultProperties = properties;
335     } while (st.hasMoreTokens());
336    
337     // this creates the configuration, all nice, ready to be returned
338     ConfigurationServant ref = new ConfigurationServant(properties, fileList, lastModified);
339     org.omg.CORBA.Object objRef = _refman.getRootPOA().servant_to_reference(ref);
340     config = ConfigurationHelper.narrow(objRef);
341    
342     } catch (Exception e) {
343     // not sure what to do here
344     // so we just log the error
345 ajm 1.10 _logger.write(toString(), Logger.ERROR, "ERROR - " + e);
346 ajm 1.8 }
347    
348     // if there isn't an entry for the requested config
349     } else {
350     _logger.write(toString(), Logger.DEBUG, "no configured config, returning " + _systemConfigFile);
351     config = _systemConfig;
352     }
353     return config;
354     }
355    
356 ajm 1.3 //---ACCESSOR/MUTATOR METHODS---
357    
358     //---ATTRIBUTES---
359    
360     /**
361 ajm 1.6 * This is the friendly identifier of the
362     * component this class is running in.
363     * eg, a Filter may be called "filter1",
364     * If this class does not have an owning
365     * component, a name from the configuration
366     * can be placed here. This name could also
367     * be changed to null for utility classes.
368     */
369     private String _name = Core.NAME;
370    
371     /**
372     * This holds a reference to the
373     * system logger that is being used.
374 ajm 1.3 */
375 ajm 1.6 private Logger _logger = ReferenceManager.getInstance().getLogger();
376 ajm 1.3
377     /**
378 ajm 1.6 * A reference to the reference manager in use
379 ajm 1.3 */
380 ajm 1.6 private ReferenceManager _refman = ReferenceManager.getInstance();
381 ajm 1.3
382     /**
383     * The root path to all configurations
384     */
385     private String _configPath;
386    
387     /**
388     * The name of the file that contains the system configuration
389     */
390     private String _systemConfigFile;
391    
392     /**
393     * An instance of the system config
394     */
395     private Configuration _systemConfig;
396 ajm 1.8
397     /**
398     * The system config file represented by a
399     * properties object.
400     */
401     private Properties _systemConfigHolder;
402 ajm 1.3
403     //---STATIC ATTRIBUTES---
404    
405     }