Version


1   package JSci;
2   
3   import java.io.*;
4   import java.net.*;
5   import java.util.ResourceBundle  ;
6   
7   /**
8   * The Version class contains information about the current and latest release.
9   * @version 1.3
10  * @author Mark Hale
11  */
12  public final class Version extends Object   implements Serializable {
13          /**
14          * Major version number.
15          */
16          public final int major;
17          /**
18          * Minor version number.
19          */
20          public final int minor;
21          /**
22          * Java platform required.
23          */
24          public final String   platform;
25          /**
26          * The URL for the home of this version.
27          */
28          public final String   home;
29          /**
30          * Gets the current version.
31          */
32          public static Version getCurrent() {
33                  ResourceBundle   bundle = ResourceBundle.getBundle("JSci.Bundle");
34                  int major = Integer.parseInt(bundle.getString("version.major"));
35                  int minor = Integer.parseInt(bundle.getString("version.minor"));
36                  String   platform = bundle.getString("version.platform");
37                  String   home = bundle.getString("version.home");
38                  return new Version(major, minor, home, platform);
39          }
40          /**
41          * Retrieves the latest version from the home URL.
42          */
43          public static Version getLatest() throws IOException {
44                  Version latest = null;
45                  try {
46                          URL serurl = new URL(getCurrent().home+"version.ser");
47                          ObjectInputStream in = new ObjectInputStream(serurl.openStream());
48                          latest = (Version) in.readObject();
49                          in.close();
50                  } catch(MalformedURLException murle) {
51                  } catch(ClassNotFoundException   cnfe) {}
52                  return latest;
53          }
54          /**
55          * Constructs a version object.
56          */
57          private Version(int major, int minor, String   home, String   platform) {
58                  this.major = major;
59                  this.minor = minor;
60                  this.home = home;
61                  this.platform = platform;
62          }
63          /**
64          * Compares two versions for equality.
65          */
66          public boolean equals(Object   o) {
67                  if(!(o instanceof Version))
68                          return false;
69                  Version ver = (Version) o;
70                  return (major == ver.major) && (minor == ver.minor) && platform.equals(ver.platform);
71          }
72      public int hashCode() {
73          return 37*(37*(37*17+major)+minor)+platform.hashCode();
74      }
75          /**
76          * Returns the version number as a string.
77          */
78          public String   toString() {
79                  return new StringBuffer  ().append(major).append('.').append(minor).toString();
80          }
81          /**
82          * Returns true if this is later than another version.
83          */
84          public boolean isLater(Version ver) {
85                  return (major>ver.major) ||
86                          (major == ver.major && minor>ver.minor);
87          }
88  }
89  
90
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