ConfigurationLocator.java

   1 /*
   2  * jSite - ConfigurationLocator.java - Copyright © 2011 David Roden
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17  */
  18
  19 package de.todesbaum.jsite.main;
  20
  21 import java.io.File;
  22 import java.util.HashMap;
  23 import java.util.Map;
  24
  25 /**
  26  * Locator for configuration files in different places.
  27  *
  28  * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  29  */
  30 public class ConfigurationLocator {
  31
  32         /**
  33          * The location of the configuration directory.
  34          *
  35          * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  36          */
  37         public enum ConfigurationLocation {
  38
  39                 /** The configuration is in the same directory as the JAR file. */
  40                 NEXT_TO_JAR_FILE,
  41
  42                 /**
  43                  * The configuration is in the user’s home directory. This is the
  44                  * pre-0.9.3 default.
  45                  */
  46                 HOME_DIRECTORY,
  47
  48                 /** Custom location. */
  49                 CUSTOM,
  50
  51         }
  52
  53         /** The possible configuration locations. */
  54         private final Map<ConfigurationLocation, String> configurationFiles = new HashMap<ConfigurationLocation, String>();
  55
  56         /**
  57          * Creates a new configuration locator. If this class is loaded from a JAR
  58          * file, {@link ConfigurationLocation#NEXT_TO_JAR_FILE} is added to the list
  59          * of possible configuration file locations.
  60          * {@link ConfigurationLocation#HOME_DIRECTORY} is always added to this
  61          * list, {@link ConfigurationLocation#CUSTOM} has to be enabled by calling
  62          * {@link #setCustomLocation(String)}.
  63          */
  64         public ConfigurationLocator() {
  65                 /* are we executed from a JAR file? */
  66                 String resource = getClass().getResource("/" + getClass().getName().replace(".", "/") + ".class").toString();
  67                 if (resource.startsWith("jar:")) {
  68                         String jarFileLocation = resource.substring(9, resource.indexOf(".jar!") + 4);
  69                         String jarFileDirectory = new File(jarFileLocation).getParent();
  70                         File configurationFile = new File(jarFileDirectory, "jSite.conf");
  71                         configurationFiles.put(ConfigurationLocation.NEXT_TO_JAR_FILE, configurationFile.getPath());
  72                 }
  73                 File homeDirectoryFile = new File(System.getProperty("user.home"), ".jSite/config7");
  74                 configurationFiles.put(ConfigurationLocation.HOME_DIRECTORY, homeDirectoryFile.getPath());
  75         }
  76
  77         //
  78         // ACCESSORS
  79         //
  80
  81         /**
  82          * Sets the location of the custom configuration file.
  83          *
  84          * @param customFile
  85          *            The custom location of the configuration file
  86          */
  87         public void setCustomLocation(String customFile) {
  88                 configurationFiles.put(ConfigurationLocation.CUSTOM, customFile);
  89         }
  90
  91         /**
  92          * Returns whether the given location is valid. Certain locations (such as
  93          * {@link ConfigurationLocation#NEXT_TO_JAR_FILE}) may be invalid in certain
  94          * circumstances (such as the application not being run from a JAR file). A
  95          * location being valid does not imply that a configuration file does exist
  96          * at the given location, use {@link #hasFile(ConfigurationLocation)} to
  97          * check for a configuration file at the desired location.
  98          *
  99          * @param configurationLocation
 100          *            The configuration location
 101          * @return {@code true} if the location is valid, {@code false} otherwise
 102          */
 103         public boolean isValidLocation(ConfigurationLocation configurationLocation) {
 104                 return configurationFiles.containsKey(configurationLocation);
 105         }
 106
 107         /**
 108          * Checks whether a configuration file exists at the given location.
 109          *
 110          * @param configurationLocation
 111          *            The configuration location
 112          * @return {@code true} if a configuration file exists at the given
 113          *         location, {@code false} otherwise
 114          */
 115         public boolean hasFile(ConfigurationLocation configurationLocation) {
 116                 if (!isValidLocation(configurationLocation)) {
 117                         return false;
 118                 }
 119                 return new File(configurationFiles.get(configurationLocation)).exists();
 120         }
 121
 122         /**
 123          * Returns the configuration file for the given location.
 124          *
 125          * @param configurationLocation
 126          *            The location to get the file for
 127          * @return The name of the configuration file at the given location, or
 128          *         {@code null} if the given location is invalid
 129          */
 130         public String getFile(ConfigurationLocation configurationLocation) {
 131                 return configurationFiles.get(configurationLocation);
 132         }
 133
 134         //
 135         // ACTIONS
 136         //
 137
 138         /**
 139          * Finds the preferred location of the configuration file.
 140          *
 141          * @see #findPreferredLocation(ConfigurationLocation)
 142          * @return The preferred location of the configuration file
 143          */
 144         public ConfigurationLocation findPreferredLocation() {
 145                 return findPreferredLocation(ConfigurationLocation.NEXT_TO_JAR_FILE);
 146         }
 147
 148         /**
 149          * Finds the preferred location of the configuration file. The following
 150          * checks are performed: if a custom configuration location has been defined
 151          * (by calling {@link #setCustomLocation(String)})
 152          * {@link ConfigurationLocation#CUSTOM} is returned. If the application is
 153          * run from a JAR file and a configuration file is found next to the JAR
 154          * file (i.e. in the same directory),
 155          * {@link ConfigurationLocation#NEXT_TO_JAR_FILE} is returned. If a
 156          * configuration file exists in the user’s home directory,
 157          * {@link ConfigurationLocation#HOME_DIRECTORY} is returned. Otherwise, the
 158          * given {@code defaultLocation} is returned.
 159          *
 160          * @param defaultLocation
 161          *            The default location to return if no other configuration file
 162          *            is found
 163          * @return The configuration location to load the configuration from
 164          */
 165         public ConfigurationLocation findPreferredLocation(ConfigurationLocation defaultLocation) {
 166                 if (hasFile(ConfigurationLocation.CUSTOM)) {
 167                         return ConfigurationLocation.CUSTOM;
 168                 }
 169                 if (hasFile(ConfigurationLocation.NEXT_TO_JAR_FILE)) {
 170                         return ConfigurationLocation.NEXT_TO_JAR_FILE;
 171                 }
 172                 if (hasFile(ConfigurationLocation.HOME_DIRECTORY)) {
 173                         return ConfigurationLocation.HOME_DIRECTORY;
 174                 }
 175                 if (isValidLocation(defaultLocation)) {
 176                         return defaultLocation;
 177                 }
 178                 return ConfigurationLocation.HOME_DIRECTORY;
 179         }
 180
 181 }