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//---PACKAGE DECLARATION--- |
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package uk.ac.ukc.iscream.core; |
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|
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//---IMPORTS--- |
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import uk.ac.ukc.iscream.core.*; |
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import java.util.*; |
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import java.io.*; |
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import org.omg.CORBA.*; |
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import org.omg.PortableServer.*; |
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|
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/** |
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* This class is essentially a Configuration factory. |
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* This class implements the Configurator IDL and allows |
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* other classes in the system ot obtain their Configuration |
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* |
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* On construction it requires a reference to the RootPOA |
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* to allow it to create Configuration objects to be |
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* returned. |
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* |
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* It also relies on the System.properties to set internal values. |
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* |
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* @author $Author: ajm4 $ |
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* @version $Id: ConfigurationManagerServant.java,v 1.4 2000/11/21 23:48:55 ajm4 Exp $ |
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*/ |
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class ConfigurationManagerServant extends ConfigurationManagerPOA { |
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|
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//---FINAL ATTRIBUTES--- |
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|
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/** |
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* The current CVS revision of this class |
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*/ |
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public final String REVISION = "$Revision: 1.4 $"; |
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|
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//---STATIC METHODS--- |
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|
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//---CONSTRUCTORS--- |
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|
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/** |
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* Creates a new ConfiguratorServant |
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* This class uses the System.properties to set internal values |
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* |
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* @param rootPOARef a reference to the RootPOA |
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* @param logRef a reference to the Logger |
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*/ |
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ConfigurationManagerServant(POA rootPOARef, Logger logRef) { |
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// assign some local variables |
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_rootPOARef = rootPOARef; |
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_logRef = logRef; |
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_configPath = System.getProperty("uk.ac.ukc.iscream.ConfigurationLocation"); |
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_systemConfigFile = System.getProperty("uk.ac.ukc.iscream.SystemConfigurationFile"); |
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|
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// load the system config |
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loadSystemConfig(); |
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|
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// log our status |
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_logRef.write(this.toString(), Logger.SYSINIT, "started"); |
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_logRef.write(this.toString(), Logger.SYSMSG, "configuration location - " + _configPath); |
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_logRef.write(this.toString(), Logger.SYSMSG, "system configuration file - " + _systemConfigFile); |
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} |
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|
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//---PUBLIC METHODS--- |
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|
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/** |
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* Returns a Configuration object which contains |
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* the configuration data requested by the calling |
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* object. |
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* |
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* This method will look in the systemConfig file |
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* for an entry for this "source", if there is no |
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* entry it returns a refernce to the system |
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* config. If there are any errors in reading the |
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* configuration, it returns null, the caller is |
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* expected to be able to handle this. |
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* |
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* This method also checks to see if the system.conf |
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* file has been updated and reloads its reference if |
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* needed. |
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* |
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* @param source the configuration required |
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* @return the Configuration |
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*/ |
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public Configuration getConfiguration(String source) { |
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_logRef.write(this.toString(), Logger.SYSMSG, "got request for " + source); |
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Configuration config = null; |
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|
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// check to see if we need to reload the system config |
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// because it has changed |
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if (isModified(_systemConfig.getFileList(), _systemConfig.getLastModified())) { |
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_logRef.write(this.toString(), Logger.SYSMSG, "system config changed"); |
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loadSystemConfig(); |
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} |
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|
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// we look for this entry in the systemConfig |
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String configFile = _systemConfig.getProperty("config." + source); |
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_logRef.write(this.toString(), Logger.DEBUG, "looking for config tree in - " + configFile); |
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|
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// if there is an entry |
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if (configFile != null) { |
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try { |
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// get the file list of includes etc + the system config |
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String fileList = _systemConfigFile + ";" + getIncludedFiles(configFile, ""); |
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_logRef.write(this.toString(), Logger.DEBUG, "config tree - " + fileList); |
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|
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// build the properites here from the filelist.... |
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StringTokenizer st = new StringTokenizer(fileList, ";"); |
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|
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// some holders for variables |
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File currentFile; |
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long lastModified, newLastModified; |
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Properties properties, prevProperties; |
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|
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// the root of all configurations will be the system config |
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// so we need to open the properties of that |
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Properties defaultProperties = new Properties(); |
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currentFile = new File(_configPath, _systemConfigFile); |
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lastModified = currentFile.lastModified(); |
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defaultProperties.load(new FileInputStream(currentFile)); |
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|
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// This loop then iterates over the file list |
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// creates the properties to be passed to the |
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// Configuration constructor |
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do { |
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properties = new Properties(defaultProperties); |
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currentFile = new File(_configPath, st.nextToken()); |
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newLastModified = currentFile.lastModified(); |
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if (newLastModified > lastModified) { |
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lastModified = newLastModified; |
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} |
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properties.load(new FileInputStream(currentFile)); |
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defaultProperties = properties; |
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} while (st.hasMoreTokens()); |
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|
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// this creates the configuration, all nice, ready to be returned |
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ConfigurationServant ref = new ConfigurationServant(properties, fileList, lastModified, _logRef); |
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org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref); |
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config = ConfigurationHelper.narrow(objRef); |
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|
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} catch (Exception e) { |
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// not sure what to do here |
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System.err.println("CONFIGURATION MANAGER ERROR: " + e); |
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e.printStackTrace(System.out); |
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} |
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|
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// if there isn't an entry for the requested config |
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} else { |
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_logRef.write(this.toString(), Logger.DEBUG, "no configured config, returning " + _systemConfigFile); |
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config = _systemConfig; |
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} |
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|
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// if this is null at this point, then there will have been an error |
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return config; |
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} |
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|
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|
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/** |
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* When passed a file list and a current value for the lastModified |
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* of the current configuration, this method compares the value |
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* to the actual value of the configuration files to determine |
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* whether or not the configuration has been modified. |
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* |
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* @param fileList a list of files that the caller uses for configuration |
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* @param lastModified the last modified date of the callers configuration |
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* |
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* @return whether or not the configuration has been modified |
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*/ |
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public boolean isModified(String fileList, long lastModified) { |
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StringTokenizer st = new StringTokenizer(fileList, ";"); |
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long newLastModified; |
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File currentFile; |
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while (st.hasMoreTokens()) { |
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currentFile = new File(_configPath, st.nextToken()); |
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newLastModified = currentFile.lastModified(); |
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if (newLastModified > lastModified) { |
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return true; |
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} |
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} |
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return false; |
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} |
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|
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/** |
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* Overrides the {@link java.lang.Object#toString() Object.toString()} |
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* method to provide clean logging (every class should have this). |
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* |
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* @return the name of this class and its CVS revision |
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*/ |
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public String toString() { |
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return this.getClass().getName() + "(" + REVISION.substring(11, REVISION.length() - 2) + ")"; |
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} |
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|
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//---PRIVATE METHODS--- |
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|
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/** |
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* This is a recursive function private to this class. |
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* It constructs a hierarchy of files as a ";" serperated |
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* string which can be used to read in the configuration. |
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* This function calls itself. |
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* |
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* @param currentFile the current file to be processed |
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* @param readFiles used for recursion purposes only, these are the files it has read so far |
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* |
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* @return the current list that has been constructed |
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* |
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* @throws IOException if there is trouble reading the file |
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* @throws FileNotFoundException is there is trouble finding the file |
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* @throws CircularIncludeException this is if a circular include is detected |
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*/ |
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private String getIncludedFiles(String currentFile, String readFiles) throws IOException, FileNotFoundException, Exception { |
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|
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// check for circular include here |
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if (hasDuplicate(currentFile, readFiles) || currentFile.equals(_systemConfigFile)) { |
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throw new CircularIncludeException(currentFile + " is included more than once"); |
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} |
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|
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// if there wasn't, we're gonna use this file, so make a note of it as read |
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// (note the use of the ";", this is for the hasDuplicate, function) |
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readFiles = readFiles + currentFile + ";"; |
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|
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Properties properties = new Properties(); |
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properties.load(new FileInputStream(new File(_configPath, currentFile))); |
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|
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// get the include property |
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String includes = properties.getProperty("include"); |
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|
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// if we're the last file with no includes, return our name |
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if (includes == null) { |
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return currentFile; |
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|
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// otherwise, recurse over our includes |
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} else { |
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StringTokenizer st = new StringTokenizer(includes, ";"); |
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String returnList= ""; |
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while (st.hasMoreTokens()) { |
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returnList = getIncludedFiles(st.nextToken(), readFiles) + ";" + returnList; |
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} |
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|
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return returnList + currentFile; |
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} |
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} |
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|
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/** |
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* This simple method checks to see if a given |
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* file exists in the given list. |
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* |
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* @param file the file to check the list for |
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* @param fileList the list to check |
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* |
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* @return if the given file appeard in the list |
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*/ |
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private boolean hasDuplicate(String file, String fileList) { |
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StringTokenizer st = new StringTokenizer(fileList, ";"); |
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while (st.hasMoreTokens()) { |
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if (file.equals(st.nextToken())) { |
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return true; |
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} |
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} |
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return false; |
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} |
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|
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/** |
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* Opens and loads the system configuration into the |
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* local reference _systemConfig |
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*/ |
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private void loadSystemConfig() { |
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_logRef.write(this.toString(), Logger.SYSMSG, "reloading " + _systemConfigFile); |
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// get a reference to the system config and store it |
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try { |
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// create the properties for the configuration |
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File systemConfigFile = new File(_configPath, _systemConfigFile); |
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Properties systemConfigHolder = new Properties(); |
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systemConfigHolder.load(new FileInputStream(systemConfigFile)); |
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|
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// create the servant |
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ConfigurationServant ref = new ConfigurationServant(systemConfigHolder, _systemConfigFile, systemConfigFile.lastModified(), _logRef); |
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org.omg.CORBA.Object objRef = _rootPOARef.servant_to_reference(ref); |
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|
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// narrow it to a Configuration |
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_systemConfig = ConfigurationHelper.narrow(objRef); |
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|
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} catch (Exception e) { |
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_logRef.write(this.toString(), Logger.FATAL, "ERROR: " + e.getMessage()); |
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} |
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} |
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|
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//---ACCESSOR/MUTATOR METHODS--- |
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|
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//---ATTRIBUTES--- |
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|
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/** |
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* Local storage of the RootPOA |
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*/ |
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private POA _rootPOARef; |
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|
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/** |
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* Local storage of the Logger |
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*/ |
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private Logger _logRef; |
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|
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/** |
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* The root path to all configurations |
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*/ |
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private String _configPath; |
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|
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/** |
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* The name of the file that contains the system configuration |
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*/ |
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private String _systemConfigFile; |
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|
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/** |
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* An instance of the system config |
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*/ |
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private Configuration _systemConfig; |
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|
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//---STATIC ATTRIBUTES--- |
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|
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} |