src/main/java/de/todesbaum/jsite/main/ConfigurationLocator.java

   1 /*
   2  * jSite - ConfigurationLocator.java - Copyright © 2011–2014 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 import java.util.Optional;
  25
  26 /**
  27  * Locator for configuration files in different places.
  28  *
  29  * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  30  */
  31 public class ConfigurationLocator {
  32
  33         /**
  34          * The location of the configuration directory.
  35          *
  36          * @author David ‘Bombe’ Roden &lt;bombe@freenetproject.org&gt;
  37          */
  38         public enum ConfigurationLocation {
  39
  40                 /** The configuration is in the same directory as the JAR file. */
  41                 NEXT_TO_JAR_FILE,
  42
  43                 /**
  44                  * The configuration is in the user’s home directory. This is the
  45                  * pre-0.9.3 default.
  46                  */
  47                 HOME_DIRECTORY,
  48
  49                 /** Custom location. */
  50                 CUSTOM,
  51
  52         }
  53
  54         /** The possible configuration locations. */
  55         private final Map<ConfigurationLocation, String> configurationFiles = new HashMap<ConfigurationLocation, String>();
  56
  57         /**
  58          * Creates a new configuration locator. If this class is loaded from a JAR
  59          * file, {@link ConfigurationLocation#NEXT_TO_JAR_FILE} is added to the list
  60          * of possible configuration file locations.
  61          * {@link ConfigurationLocation#HOME_DIRECTORY} is always added to this
  62          * list, {@link ConfigurationLocation#CUSTOM} has to be enabled by calling
  63          * {@link #setCustomLocation(String)}.
  64          */
  65         public ConfigurationLocator(JarFileLocator jarFileLocator) {
  66                 /* are we executed from a JAR file? */
  67                 Optional<File> jarFile = jarFileLocator.locateJarFile();
  68                 if (jarFile.isPresent()) {
  69                         File configurationFile = new File(jarFile.get().getParent(), "jSite.conf");
  70                         configurationFiles.put(ConfigurationLocation.NEXT_TO_JAR_FILE, configurationFile.getPath());
  71                 }
  72                 File homeDirectoryFile = new File(System.getProperty("user.home"), ".jSite/config7");
  73                 configurationFiles.put(ConfigurationLocation.HOME_DIRECTORY, homeDirectoryFile.getPath());
  74         }
  75
  76         //
  77         // ACCESSORS
  78         //
  79
  80         /**
  81          * Sets the location of the custom configuration file.
  82          *
  83          * @param customFile
  84          *            The custom location of the configuration file
  85          */
  86         public void setCustomLocation(String customFile) {
  87                 configurationFiles.put(ConfigurationLocation.CUSTOM, customFile);
  88         }
  89
  90         /**
  91          * Returns whether the given location is valid. Certain locations (such as
  92          * {@link ConfigurationLocation#NEXT_TO_JAR_FILE}) may be invalid in certain
  93          * circumstances (such as the application not being run from a JAR file). A
  94          * location being valid does not imply that a configuration file does exist
  95          * at the given location, use {@link #hasFile(ConfigurationLocation)} to
  96          * check for a configuration file at the desired location.
  97          *
  98          * @param configurationLocation
  99          *            The configuration location
 100          * @return {@code true} if the location is valid, {@code false} otherwise
 101          */
 102         public boolean isValidLocation(ConfigurationLocation configurationLocation) {
 103                 return configurationFiles.containsKey(configurationLocation);
 104         }
 105
 106         /**
 107          * Checks whether a configuration file exists at the given location.
 108          *
 109          * @param configurationLocation
 110          *            The configuration location
 111          * @return {@code true} if a configuration file exists at the given
 112          *         location, {@code false} otherwise
 113          */
 114         public boolean hasFile(ConfigurationLocation configurationLocation) {
 115                 if (!isValidLocation(configurationLocation)) {
 116                         return false;
 117                 }
 118                 return new File(configurationFiles.get(configurationLocation)).exists();
 119         }
 120
 121         /**
 122          * Returns the configuration file for the given location.
 123          *
 124          * @param configurationLocation
 125          *            The location to get the file for
 126          * @return The name of the configuration file at the given location, or
 127          *         {@code null} if the given location is invalid
 128          */
 129         public String getFile(ConfigurationLocation configurationLocation) {
 130                 return configurationFiles.get(configurationLocation);
 131         }
 132
 133         //
 134         // ACTIONS
 135         //
 136
 137         /**
 138          * Finds the preferred location of the configuration file.
 139          *
 140          * @see #findPreferredLocation(ConfigurationLocation)
 141          * @return The preferred location of the configuration file
 142          */
 143         public ConfigurationLocation findPreferredLocation() {
 144                 return findPreferredLocation(ConfigurationLocation.NEXT_TO_JAR_FILE);
 145         }
 146
 147         /**
 148          * Finds the preferred location of the configuration file. The following
 149          * checks are performed: if a custom configuration location has been defined
 150          * (by calling {@link #setCustomLocation(String)})
 151          * {@link ConfigurationLocation#CUSTOM} is returned. If the application is
 152          * run from a JAR file and a configuration file is found next to the JAR
 153          * file (i.e. in the same directory),
 154          * {@link ConfigurationLocation#NEXT_TO_JAR_FILE} is returned. If a
 155          * configuration file exists in the user’s home directory,
 156          * {@link ConfigurationLocation#HOME_DIRECTORY} is returned. Otherwise, the
 157          * given {@code defaultLocation} is returned.
 158          *
 159          * @param defaultLocation
 160          *            The default location to return if no other configuration file
 161          *            is found
 162          * @return The configuration location to load the configuration from
 163          */
 164         public ConfigurationLocation findPreferredLocation(ConfigurationLocation defaultLocation) {
 165                 if (hasFile(ConfigurationLocation.CUSTOM)) {
 166                         return ConfigurationLocation.CUSTOM;
 167                 }
 168                 if (hasFile(ConfigurationLocation.NEXT_TO_JAR_FILE)) {
 169                         return ConfigurationLocation.NEXT_TO_JAR_FILE;
 170                 }
 171                 if (hasFile(ConfigurationLocation.HOME_DIRECTORY)) {
 172                         return ConfigurationLocation.HOME_DIRECTORY;
 173                 }
 174                 if (isValidLocation(defaultLocation)) {
 175                         return defaultLocation;
 176                 }
 177                 return ConfigurationLocation.HOME_DIRECTORY;
 178         }
 179
 180 }