/***************************************
 *                                     *
 *  JBoss: The OpenSource J2EE WebOS   *
 *                                     *
 *  Distributable under LGPL license.  *
 *  See terms of license at gnu.org.   *
 *                                     *
 ***************************************/

package org.jboss;

import java.io.IOException;
import java.io.InputStream;

import java.util.Collections;
import java.util.Map;
import java.util.Properties;
import java.util.Date;

/**
 * Provides access to JBoss version (and build) properties.
 *
 * @author     <a href="mailto:jason@planet57.com">Jason Dillon</a>
 * @version    $Revision: 1.1 $
 */
public final class Version
{
   public final static String VERSION_MAJOR = "version.major";
   public final static String VERSION_MINOR = "version.minor";
   public final static String VERSION_REVISION = "version.revision";
   public final static String VERSION_TAG = "version.tag";
   public final static String VERSION_NAME = "version.name";

   public final static String BUILD_NUMBER = "build.number";
   public final static String BUILD_ID = "build.id";
   public final static String BUILD_DATE = "build.day";

   /**
    * The single instance.
    */
   private static Version instance = null;

   /**
    * The version properties.
    */
   private Properties props;

   /**
    * Do not allow direct public construction.
    */
   private Version()
   {
      props = loadProperties();
   }

   /**
    * Get the single <tt>Version</tt> instance.
    *
    * @return    The single <tt>Version</tt> instance.
    */
   public static Version getInstance()
   {
      if (instance == null)
      {
         instance = new Version();
      }
      return instance;
   }

   /**
    * Returns an unmodifiable map of version properties.
    *
    * @return    An unmodifiable map of version properties.
    */
   public Map getProperties()
   {
      return Collections.unmodifiableMap(props);
   }

   /**
    * Returns the value for the given property name.
    *
    * @param     name - The name of the property.
    * @return    The property value or null if the property is not set.
    */
   public String getProperty(final String name)
   {
      return props.getProperty(name);
   }

   /**
    * Returns the major number of the version.
    *
    * @return    The major number of the version.
    */
   public int getMajor()
   {
      return getIntProperty(VERSION_MAJOR);
   }

   /**
    * Returns the minor number of the version.
    *
    * @return    The minor number of the version.
    */
   public int getMinor()
   {
      return getIntProperty(VERSION_MINOR);
   }

   /**
    * Returns the revision number of the version.
    *
    * @return    The revision number of the version.
    */
   public int getRevision()
   {
      return getIntProperty(VERSION_REVISION);
   }

   /**
    * Returns the tag of the version.
    *
    * @return    The tag of the version.
    */
   public String getTag()
   {
      return props.getProperty(VERSION_TAG);
   }

   /**
    * Returns the name number of the version.
    *
    * @return    The name of the version.
    */
   public String getName()
   {
      return props.getProperty(VERSION_NAME);
   }

   /**
    * Returns the build identifier for this version.
    *
    * @return    The build identifier for this version.
    */
   public String getBuildID()
   {
      return props.getProperty(BUILD_ID);
   }

   /**
    * Returns the build number for this version.
    *
    * @return    The build number for this version.
    */
   public String getBuildNumber()
   {
      return props.getProperty(BUILD_NUMBER);
   }

   /**
    * Returns the build date for this version.
    *
    * @return    The build date for this version.
    */
   public String getBuildDate()
   {
      return props.getProperty(BUILD_DATE);
   }
   
   /**
    * Returns the version information as a string.
    *
    * @return    Basic information as a string.
    */
   public String toString()
   {
      StringBuffer buff = new StringBuffer();

      buff.append(getMajor()).append(".");
      buff.append(getMinor()).append(".");
      buff.append(getRevision()).append(getTag());
      buff.append("(").append(getBuildID()).append(")");

      return buff.toString();
   }

   /**
    * Returns a property value as an int.
    *
    * @param    name - The name of the property.
    * @return   The property value, or -1 if there was a problem converting
    *           it to an int.
    */
   private int getIntProperty(final String name)
   {
      try {
         return Integer.valueOf(props.getProperty(name)).intValue();
      }
      catch (Exception e) {
         return -1;
      }
   }

   /**
    * Returns a property value as a long.
    *
    * @param    name - The name of the property.
    * @return   The property value, or -1 if there was a problem converting
    *           it to an long.
    */
   private long getLongProperty(final String name)
   {
      try {
         return Long.valueOf(props.getProperty(name)).longValue();
      }
      catch (Exception e) {
         return -1;
      }
   }
   
   /**
    * Load the version properties from a resource.
    */
   private Properties loadProperties()
   {
      props = new Properties();

      try
      {
         InputStream in =
               Version.class.getResourceAsStream("/org/jboss/version.properties");

         props.load(in);
         in.close();
      }
      catch (IOException e)
      {
         throw new Error("Missing version.properties");
      }

      return props;
   }
}