- * The most useful method is the isCompatibleWith() method that
- * compares a desired version of a specification with the version of the
- * specification as implemented by a package. A package is considered
- * compatible with another version if the version of the specification is
- * equal or higher then the requested version. Version numbers are represented
- * as strings of positive numbers separated by dots (e.g. "1.2.0").
- * The first number is called the major number, the second the minor,
- * the third the micro, etc. A version is considered higher then another
- * version if it has a bigger major number then the another version or when
- * the major numbers of the versions are equal if it has a bigger minor number
- * then the other version, etc. (If a version has no minor, micro, etc numbers
- * then they are considered the be 0.)
- *
- * @since 1.2
- * @author Mark Wielaard (mark@klomp.org)
- */
-public class Package
-{
- /** The name of the Package */
- final private String name;
-
- /** The name if the implementation */
- final private String implTitle;
- /** The vendor that wrote this implementation */
- final private String implVendor;
- /** The version of this implementation */
- final private String implVersion;
-
- /** The name of the specification */
- final private String specTitle;
- /** The name of the specification designer */
- final private String specVendor;
- /** The version of this specification */
- final private String specVersion;
-
- /** If sealed the origin of the package classes, otherwise null */
- final private URL sealed;
-
- /**
- * A package local constructor for the Package class.
- * All parameters except the name of the package may be
- * null.
- * There are no public constructors defined for Package this is a package
- * local constructor that is used by java.lang.Classloader.definePackage().
- *
- * @param name The name of the Package
- * @param specTitle The name of the specification
- * @param specVendor The name of the specification designer
- * @param specVersion The version of this specification
- * @param implTitle The name of the implementation
- * @param implVendor The vendor that wrote this implementation
- * @param implVersion The version of this implementation
- * @param sealed If sealed the origin of the package classes
- */
- Package(String name,
- String specTitle, String specVendor, String specVersion,
- String implTitle, String implVendor, String implVersion, URL sealed)
- {
- if (name == null)
- throw new IllegalArgumentException("null Package name");
-
- this.name = name;
-
- this.implTitle = implTitle;
- this.implVendor = implVendor;
- this.implVersion = implVersion;
-
- this.specTitle = specTitle;
- this.specVendor = specVendor;
- this.specVersion = specVersion;
-
- this.sealed = sealed;
- }
-
- /**
- * Returns the Package name.
- */
- public String getName()
- {
- return name;
- }
-
- /**
- * Returns the name of the implementation or null if unknown.
- */
- public String getImplementationTitle()
- {
- return implTitle;
- }
-
- /**
- * Returns the vendor that wrote this implementation or null if unknown.
- */
- public String getImplementationVendor()
- {
- return implVendor;
- }
-
- /**
- * Returns the version of this implementation or null if unknown.
- */
- public String getImplementationVersion()
- {
- return implVersion;
- }
-
- /**
- * Returns the name of the specification or null if unknown.
- */
- public String getSpecificationTitle()
- {
- return specTitle;
- }
-
- /**
- * Returns the name of the specification designer or null if unknown.
- */
- public String getSpecificationVendor()
- {
- return specVendor;
- }
-
- /**
- * Returns the version of the specification or null if unknown.
- */
- public String getSpecificationVersion()
- {
- return specVersion;
- }
-
- /**
- * Returns true if this Package is sealed.
- */
- public boolean isSealed()
- {
- return (sealed != null);
- }
-
- /**
- * Returns true if this Package is sealed and the origin of the classes is
- * the given URL.
- *
- * @param url
- */
- public boolean isSealed(URL url)
- {
- return url.equals(sealed);
- }
-
- /**
- * Checks if the version of the specification is higher or at least as high
- * as the desired version.
- * @param version the (minimal) desired version of the specification
- * @exception NumberFormatException when either version or the
- * specification version is not a correctly formatted version number
- * @exception NullPointerException if the supplied version or the
- * Package specification version is null.
- */
- public boolean isCompatibleWith(String version) throws NumberFormatException
- {
- StringTokenizer versionTokens = new StringTokenizer(version, ".");
- StringTokenizer specTokens = new StringTokenizer(specVersion, ".");
- try
- {
- while (versionTokens.hasMoreElements())
- {
- int vers = Integer.parseInt(versionTokens.nextToken());
- int spec = Integer.parseInt(specTokens.nextToken());
- if (spec < vers)
- return false;
- else if (spec > vers)
- return true;
- // They must be equal, next Token please!
- }
- }
- catch (NoSuchElementException e)
- {
- // this must have been thrown by spec.netToken() so return false
- return false;
- }
-
- // They must have been exactly the same version.
- // Or the specVersion has more subversions. That is also good.
- return true;
- }
-
- /**
- * Returns the named package if it is known by the callers class loader.
- * It may return null if the package is unknown, when there is no
- * information on that particular package available or when the callers
- * classloader is null.
- * @param name the name of the desired package
- */
- public static Package getPackage(String name)
- {
- // Get the caller's classloader
- SecurityManager sm = System.getSecurityManager();
- Class c = sm.getClassContext()[1];
- ClassLoader cl = c.getClassLoader();
-
- if (cl != null)
- return cl.getPackage(name);
- else
- return null;
- }
-
- /**
- * Returns all the packages that are known to the callers class loader.
- * It may return an empty array if the classloader of the caller is null.
- */
- public static Package[] getPackages()
- {
- // Get the caller's classloader
- SecurityManager sm = System.getSecurityManager();
- Class c = sm.getClassContext()[1];
- ClassLoader cl = c.getClassLoader();
-
- if (cl != null)
- return cl.getPackages();
- else
- return new Package[0];
- }
-
- /**
- * Returns the hashCode of the name of this package.
- */
- public int hashCode()
- {
- return name.hashCode();
- }
-
- /**
- * Returns a string representation of this package name, specification,
- * implementation and class origin if sealed.
- */
- public String toString()
- {
- return "package: " + name +
- " spec: " + specTitle +
- " version: " + specVersion +
- " vendor: " + specVendor +
- " implementation: " + implTitle +
- " version: " + implVersion +
- " vendor: " + implVendor + " sealed: " + sealed;
- }
-}