server/core/ConfigurationManagerServant.java

//---PACKAGE DECLARATION---

//---IMPORTS---
import uk.ac.ukc.iscream.core.*;
import java.util.*;
import java.io.*;
import org.omg.CORBA.*;
import org.omg.PortableServer.*;

/**
 * This class is essentially a Configuration factory.
 * This class implements the Configurator IDL and allows
 * other classes in the system ot obtain their Configuration
 *
 * On construction it requires a reference to the RootPOA
 * to allow it to create Configuration objects to be
 * returned.
 *
 * It also relies on the System.properties to set internal values.
 *
 * @author  $Author: tdb1 $
 * @version $Id: ConfigurationManagerServant.java,v 1.2 2000/11/21 15:08:42 tdb1 Exp $
 */
class ConfigurationManagerServant extends ConfigurationManagerPOA {

//---FINAL ATTRIBUTES---

    /**
     * The current CVS revision of this class
     */
    public final String REVISION = "$Revision: 1.2 $";
    
//---STATIC METHODS---

//---CONSTRUCTORS---

    /**
     * Creates a new ConfiguratorServant
     * This class uses the System.properties to set internal values
     *
     * @param rootPOARef a reference to the RootPOA
     * @param logRef a reference to the Logger
     */
    ConfigurationManagerServant(POA rootPOARef, Logger logRef) {
        // assign some local variables
        _rootPOARef = rootPOARef;
        _logRef = logRef;
        _configPath = System.getProperty("uk.ac.ukc.iscream.ConfigurationLocation");
        _systemConfigFile = System.getProperty("uk.ac.ukc.iscream.SystemConfigurationFile");

        // load the system config
        loadSystemConfig();

        // log our status
        _logRef.write(this.toString(), Logger.SYSINIT, "started");
        _logRef.write(this.toString(), Logger.SYSMSG, "configuration location - " + _configPath);
        _logRef.write(this.toString(), Logger.SYSMSG, "system configuration file - " + _systemConfigFile);
    }

//---PUBLIC METHODS---
    
    /**
     * Returns a Configuration object which contains
     * the configuration data requested by the calling
     * object.
     *
     * This method will look in the systemConfig file
     * for an entry for this "source", if there is no
     * entry it returns a refernce to the system
     * config.  If there are any errors in reading the 
     * configuration, it returns null, the caller is 
     * expected to be able to handle this.
     *
     * This method also checks to see if the system.conf
     * file has been updated and reloads its reference if
     * needed.
     *
     * @param source the configuration required
     * @return the Configuration
     */
    public Configuration getConfiguration(String source) {
        _logRef.write(this.toString(), Logger.SYSMSG, "got request for " + source);
        Configuration config = null;
        
        // check to see if we need to reload the system config
        // because it has changed
        if (isModified(_systemConfig.getFileList(), _systemConfig.getLastModified())) {
            _logRef.write(this.toString(), Logger.SYSMSG, "system config changed");
            loadSystemConfig();
        }

        // we look for this entry in the systemConfig
        String configFile = _systemConfig.getProperty("config." + source);
        _logRef.write(this.toString(), Logger.DEBUG, "looking for config tree in - " + configFile);

        // if there is an entry
        if (configFile != null) {
            try {
                // get the file list of includes etc
                String fileList = getIncludedFiles(configFile);            
                _logRef.write(this.toString(), Logger.DEBUG, "config tree - " + fileList);
                
                // build the properites here from the filelist.... 
                StringTokenizer st = new StringTokenizer(fileList, ";");
                
                // some holders for variables
                File currentFile;
                long lastModified, newLastModified;
                Properties properties, prevProperties;
                
                // the root of all configurations will be the system config
                // so we need to open the properties of that
                Properties defaultProperties = new Properties();
                currentFile = new File(_configPath, _systemConfigFile);
                lastModified = currentFile.lastModified();
                defaultProperties.load(new FileInputStream(currentFile));
                
                // This loop then iterates over the file list
                // creates the properties to be passed to the
                // Configuration constructor
                do {
                    properties = new Properties(defaultProperties);
                    currentFile = new File(_configPath, st.nextToken());
                    newLastModified = currentFile.lastModified();
                    if (newLastModified > lastModified) {
                        lastModified = newLastModified;
                    }
                    properties.load(new FileInputStream(currentFile));
                    defaultProperties = properties;
                } while (st.hasMoreTokens());

                // this creates the configuration, all nice, ready to be returned
                ConfigurationServant ref = new ConfigurationServant(properties, fileList, lastModified, _logRef);
                org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref);
                config = ConfigurationHelper.narrow(objRef);

            } catch (Exception e) {
                // not sure what to do here
                System.err.println("CONFIGURATION MANAGER ERROR: " + e);
                e.printStackTrace(System.out);
            }
            
        // if there isn't an entry for he requested config
        } else {
            _logRef.write(this.toString(), Logger.DEBUG, "no configured config, returning " + _systemConfigFile);
            config = _systemConfig;
        }
        
        // if this is null at this point, then there will have been an error
        return config;
    }
    
    
    /**
     * When passed a file list and a current value for the lastModified
     * of the current configuration, this method compares the value
     * to the actual value of the configuration files to determine 
     * whether or not the configuration has been modified.
     *
     * @param fileList a list of files that the caller uses for configuration
     * @param lastModified the last modified date of the callers configuration
     *
     * @return whether or not the configuration has been modified
     */
    public boolean isModified(String fileList, long lastModified) {
        StringTokenizer st = new StringTokenizer(fileList, ";");
        long newLastModified;
        File currentFile;
        while (st.hasMoreTokens()) {
            currentFile = new File(_configPath, st.nextToken());
            newLastModified = currentFile.lastModified();
            if (newLastModified > lastModified) {
                return true;
            }
        }
        return false;
    }
    
    /**
     * Overrides the {@link java.lang.Object#toString() Object.toString()}
     * method to provide clean logging (every class should have this).
     *
     * @return the name of this class and its CVS revision
     */
    public String toString() {
        return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
    }

//---PRIVATE METHODS---

    /**
     * This is a recursive function private to this class.
     * It constructs a hierarchy of files as a ";" serperated
     * string which can be used to read in the configuration.
     * This function calls itself.
     * 
     * @param currentFile the current file to be processed
     * 
     * @return the current list that has been constructed
     *
     * @throws IOException if there is trouble reading the file
     * @throws FileNotFoundException is there is trouble finding the file
     */
    private String getIncludedFiles(String currentFile) throws IOException, FileNotFoundException {
        Properties properties = new Properties();
        properties.load(new FileInputStream(new File(_configPath, currentFile)));
        String includes = properties.getProperty("include");
        if (includes == null) {
            return currentFile;
        } else {
            StringTokenizer st = new StringTokenizer(includes, ";");
            String returnList= "";
            while (st.hasMoreTokens()) {
                String nextFile = st.nextToken();
                returnList = getIncludedFiles(nextFile) + ";" + returnList;
            }
            return returnList + currentFile;
        }
    }

    /**
     * Opens and loads the system configuration into the 
     * local reference _systemConfig
     */
    private void loadSystemConfig() {
        _logRef.write(this.toString(), Logger.SYSMSG, "reloading" + _systemConfigFile);
        // get a reference to the system config and store it
        try {
            // create the properties for the configuration
            File systemConfigFile = new File(_configPath, _systemConfigFile);
            Properties systemConfigHolder = new Properties();
            systemConfigHolder.load(new FileInputStream(systemConfigFile));
                        
            // create the servant
            ConfigurationServant ref = new ConfigurationServant(systemConfigHolder, _systemConfigFile, systemConfigFile.lastModified(), _logRef);
            org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref);
            
            // narrow it to a Configuration
            _systemConfig = ConfigurationHelper.narrow(objRef);
            
        } catch (Exception e) {
            _logRef.write(this.toString(), Logger.FATAL, "ERROR: " + e.getMessage());
        }
    }

//---ACCESSOR/MUTATOR METHODS---

//---ATTRIBUTES---

    /**
     * Local storage of the RootPOA
     */
    private POA _rootPOARef;
    
    /**
     * Local storage of the Logger
     */
    private Logger _logRef;
    
    /**
     * The root path to all configurations
     */
    private String _configPath;
    
    /**
     * The name of the file that contains the system configuration
     */
    private String _systemConfigFile;
    
    /**
     * An instance of the system config
     */
    private Configuration _systemConfig;
    
//---STATIC ATTRIBUTES---
    
}
Revision:	1.3
Committed:	Tue Nov 21 21:58:52 2000 UTC (23 years, 6 months ago) by ajm
Branch:	MAIN
Changes since 1.2:	+277 -235 lines
Log Message:	Tided up the code LOADS...all functionality remains Added a local instance of the systemConfiguration just because it may be needed alot...if it remains unchanged...it means handing it back as the default config will be a bit more effecient. (I think)
#	User	Rev	Content
1	ajm	1.3	//---PACKAGE DECLARATION---
2
3			//---IMPORTS---
4			import uk.ac.ukc.iscream.core.*;
5			import java.util.*;
6			import java.io.*;
7			import org.omg.CORBA.*;
8			import org.omg.PortableServer.*;
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			* @author $Author: tdb1 $
22			* @version $Id: ConfigurationManagerServant.java,v 1.2 2000/11/21 15:08:42 tdb1 Exp $
23			*/
24			class ConfigurationManagerServant extends ConfigurationManagerPOA {
25
26			//---FINAL ATTRIBUTES---
27
28			/**
29			* The current CVS revision of this class
30			*/
31			public final String REVISION = "$Revision: 1.2 $";
32
33			//---STATIC METHODS---
34
35			//---CONSTRUCTORS---
36
37			/**
38			* Creates a new ConfiguratorServant
39			* This class uses the System.properties to set internal values
40			*
41			* @param rootPOARef a reference to the RootPOA
42			* @param logRef a reference to the Logger
43			*/
44			ConfigurationManagerServant(POA rootPOARef, Logger logRef) {
45			// assign some local variables
46			_rootPOARef = rootPOARef;
47			_logRef = logRef;
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			_logRef.write(this.toString(), Logger.SYSINIT, "started");
56			_logRef.write(this.toString(), Logger.SYSMSG, "configuration location - " + _configPath);
57			_logRef.write(this.toString(), Logger.SYSMSG, "system configuration file - " + _systemConfigFile);
58			}
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			_logRef.write(this.toString(), Logger.SYSMSG, "got request for " + source);
83			Configuration config = null;
84
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			_logRef.write(this.toString(), Logger.SYSMSG, "system config changed");
89			loadSystemConfig();
90			}
91
92			// we look for this entry in the systemConfig
93			String configFile = _systemConfig.getProperty("config." + source);
94			_logRef.write(this.toString(), Logger.DEBUG, "looking for config tree in - " + configFile);
95
96			// if there is an entry
97			if (configFile != null) {
98			try {
99			// get the file list of includes etc
100			String fileList = getIncludedFiles(configFile);
101			_logRef.write(this.toString(), Logger.DEBUG, "config tree - " + fileList);
102
103			// build the properites here from the filelist....
104			StringTokenizer st = new StringTokenizer(fileList, ";");
105
106			// some holders for variables
107			File currentFile;
108			long lastModified, newLastModified;
109			Properties properties, prevProperties;
110
111			// the root of all configurations will be the system config
112			// so we need to open the properties of that
113			Properties defaultProperties = new Properties();
114			currentFile = new File(_configPath, _systemConfigFile);
115			lastModified = currentFile.lastModified();
116			defaultProperties.load(new FileInputStream(currentFile));
117
118			// This loop then iterates over the file list
119			// creates the properties to be passed to the
120			// Configuration constructor
121			do {
122			properties = new Properties(defaultProperties);
123			currentFile = new File(_configPath, st.nextToken());
124			newLastModified = currentFile.lastModified();
125			if (newLastModified > lastModified) {
126			lastModified = newLastModified;
127			}
128			properties.load(new FileInputStream(currentFile));
129			defaultProperties = properties;
130			} while (st.hasMoreTokens());
131
132			// this creates the configuration, all nice, ready to be returned
133			ConfigurationServant ref = new ConfigurationServant(properties, fileList, lastModified, _logRef);
134			org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref);
135			config = ConfigurationHelper.narrow(objRef);
136
137			} catch (Exception e) {
138			// not sure what to do here
139			System.err.println("CONFIGURATION MANAGER ERROR: " + e);
140			e.printStackTrace(System.out);
141			}
142
143			// if there isn't an entry for he requested config
144			} else {
145			_logRef.write(this.toString(), Logger.DEBUG, "no configured config, returning " + _systemConfigFile);
146			config = _systemConfig;
147			}
148
149			// if this is null at this point, then there will have been an error
150			return config;
151			}
152
153
154			/**
155			* When passed a file list and a current value for the lastModified
156			* of the current configuration, this method compares the value
157			* to the actual value of the configuration files to determine
158			* whether or not the configuration has been modified.
159			*
160			* @param fileList a list of files that the caller uses for configuration
161			* @param lastModified the last modified date of the callers configuration
162			*
163			* @return whether or not the configuration has been modified
164			*/
165			public boolean isModified(String fileList, long lastModified) {
166			StringTokenizer st = new StringTokenizer(fileList, ";");
167			long newLastModified;
168			File currentFile;
169			while (st.hasMoreTokens()) {
170			currentFile = new File(_configPath, st.nextToken());
171			newLastModified = currentFile.lastModified();
172			if (newLastModified > lastModified) {
173			return true;
174			}
175			}
176			return false;
177			}
178
179			/**
180			* Overrides the {@link java.lang.Object#toString() Object.toString()}
181			* method to provide clean logging (every class should have this).
182			*
183			* @return the name of this class and its CVS revision
184			*/
185			public String toString() {
186			return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")";
187			}
188
189			//---PRIVATE METHODS---
190
191			/**
192			* This is a recursive function private to this class.
193			* It constructs a hierarchy of files as a ";" serperated
194			* string which can be used to read in the configuration.
195			* This function calls itself.
196			*
197			* @param currentFile the current file to be processed
198			*
199			* @return the current list that has been constructed
200			*
201			* @throws IOException if there is trouble reading the file
202			* @throws FileNotFoundException is there is trouble finding the file
203			*/
204			private String getIncludedFiles(String currentFile) throws IOException, FileNotFoundException {
205			Properties properties = new Properties();
206			properties.load(new FileInputStream(new File(_configPath, currentFile)));
207			String includes = properties.getProperty("include");
208			if (includes == null) {
209			return currentFile;
210			} else {
211			StringTokenizer st = new StringTokenizer(includes, ";");
212			String returnList= "";
213			while (st.hasMoreTokens()) {
214			String nextFile = st.nextToken();
215			returnList = getIncludedFiles(nextFile) + ";" + returnList;
216			}
217			return returnList + currentFile;
218			}
219			}
220
221			/**
222			* Opens and loads the system configuration into the
223			* local reference _systemConfig
224			*/
225			private void loadSystemConfig() {
226			_logRef.write(this.toString(), Logger.SYSMSG, "reloading" + _systemConfigFile);
227			// get a reference to the system config and store it
228			try {
229			// create the properties for the configuration
230			File systemConfigFile = new File(_configPath, _systemConfigFile);
231			Properties systemConfigHolder = new Properties();
232			systemConfigHolder.load(new FileInputStream(systemConfigFile));
233
234			// create the servant
235			ConfigurationServant ref = new ConfigurationServant(systemConfigHolder, _systemConfigFile, systemConfigFile.lastModified(), _logRef);
236			org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref);
237
238			// narrow it to a Configuration
239			_systemConfig = ConfigurationHelper.narrow(objRef);
240
241			} catch (Exception e) {
242			_logRef.write(this.toString(), Logger.FATAL, "ERROR: " + e.getMessage());
243			}
244			}
245
246			//---ACCESSOR/MUTATOR METHODS---
247
248			//---ATTRIBUTES---
249
250			/**
251			* Local storage of the RootPOA
252			*/
253			private POA _rootPOARef;
254
255			/**
256			* Local storage of the Logger
257			*/
258			private Logger _logRef;
259
260			/**
261			* The root path to all configurations
262			*/
263			private String _configPath;
264
265			/**
266			* The name of the file that contains the system configuration
267			*/
268			private String _systemConfigFile;
269
270			/**
271			* An instance of the system config
272			*/
273			private Configuration _systemConfig;
274
275			//---STATIC ATTRIBUTES---
276
277			}