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Diffstat (limited to 'libjava/java/lang/Package.java')
| -rw-r--r-- | libjava/java/lang/Package.java | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/libjava/java/lang/Package.java b/libjava/java/lang/Package.java new file mode 100644 index 0000000..26bcb98 --- /dev/null +++ b/libjava/java/lang/Package.java @@ -0,0 +1,287 @@ +/* java.lang.Package - Everything you ever wanted to know about a package. + Copyright (C) 2000, 2001 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ + +package java.lang; + +import java.net.URL; +import java.util.NoSuchElementException; +import java.util.StringTokenizer; + +/** + * Everything you ever wanted to know about a package. This class makes it + * possible to attach specification and implementation information to a + * package as explained in the + * <a href="http://java.sun.com/products/jdk/1.3/docs/guide/versioning/spec/VersioningSpecification.html#PackageVersionSpecification">Package Versioning Specification</a> + * section of the + * <a href="http://java.sun.com/products/jdk/1.3/docs/guide/versioning/spec/VersioningSpecification.html">Product Versioning Specification</a>. + * It also allows packages to be sealed with respect to the originating URL. + * <p> + * The most usefull method is the <code>isCompatibleWith()</code> 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 seperated 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 <code>name</code> of the package may be + * <code>null</code>. + * 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; + } +} |