299 lines
9.4 KiB
Java
299 lines
9.4 KiB
Java
/* java.lang.Package - Everything you ever wanted to know about a package.
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Copyright (C) 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.lang;
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import java.net.URL;
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import java.util.NoSuchElementException;
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import java.util.StringTokenizer;
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/**
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* Everything you ever wanted to know about a package. This class makes it
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* possible to attach specification and implementation information to a
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* package as explained in the
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* <a href="http://java.sun.com/products/jdk/1.3/docs/guide/versioning/spec/VersioningSpecification.html#PackageVersionSpecification">Package Versioning Specification</a>
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* section of the
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* <a href="http://java.sun.com/products/jdk/1.3/docs/guide/versioning/spec/VersioningSpecification.html">Product Versioning Specification</a>.
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* It also allows packages to be sealed with respect to the originating URL.
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* <p>
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* The most useful method is the <code>isCompatibleWith()</code> method that
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* compares a desired version of a specification with the version of the
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* specification as implemented by a package. A package is considered
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* compatible with another version if the version of the specification is
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* equal or higher then the requested version. Version numbers are represented
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* as strings of positive numbers separated by dots (e.g. "1.2.0").
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* The first number is called the major number, the second the minor,
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* the third the micro, etc. A version is considered higher then another
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* version if it has a bigger major number then the another version or when
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* the major numbers of the versions are equal if it has a bigger minor number
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* then the other version, etc. (If a version has no minor, micro, etc numbers
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* then they are considered the be 0.)
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*
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* @since 1.2
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* @author Mark Wielaard (mark@klomp.org)
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*/
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public class Package
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{
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/** The name of the Package */
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final private String name;
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/** The name if the implementation */
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final private String implTitle;
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/** The vendor that wrote this implementation */
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final private String implVendor;
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/** The version of this implementation */
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final private String implVersion;
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/** The name of the specification */
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final private String specTitle;
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/** The name of the specification designer */
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final private String specVendor;
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/** The version of this specification */
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final private String specVersion;
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/** If sealed the origin of the package classes, otherwise null */
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final private URL sealed;
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/**
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* A package local constructor for the Package class.
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* All parameters except the <code>name</code> of the package may be
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* <code>null</code>.
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* There are no public constructors defined for Package this is a package
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* local constructor that is used by java.lang.Classloader.definePackage().
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*
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* @param name The name of the Package
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* @param specTitle The name of the specification
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* @param specVendor The name of the specification designer
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* @param specVersion The version of this specification
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* @param implTitle The name of the implementation
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* @param implVendor The vendor that wrote this implementation
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* @param implVersion The version of this implementation
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* @param sealed If sealed the origin of the package classes
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*/
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Package(String name,
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String specTitle, String specVendor, String specVersion,
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String implTitle, String implVendor, String implVersion, URL sealed)
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{
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if (name == null)
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throw new IllegalArgumentException("null Package name");
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this.name = name;
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this.implTitle = implTitle;
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this.implVendor = implVendor;
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this.implVersion = implVersion;
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this.specTitle = specTitle;
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this.specVendor = specVendor;
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this.specVersion = specVersion;
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this.sealed = sealed;
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}
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/**
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* Returns the Package name.
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*/
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public String getName()
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{
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return name;
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}
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/**
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* Returns the name of the implementation or null if unknown.
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*/
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public String getImplementationTitle()
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{
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return implTitle;
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}
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/**
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* Returns the vendor that wrote this implementation or null if unknown.
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*/
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public String getImplementationVendor()
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{
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return implVendor;
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}
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/**
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* Returns the version of this implementation or null if unknown.
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*/
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public String getImplementationVersion()
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{
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return implVersion;
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}
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/**
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* Returns the name of the specification or null if unknown.
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*/
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public String getSpecificationTitle()
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{
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return specTitle;
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}
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/**
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* Returns the name of the specification designer or null if unknown.
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*/
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public String getSpecificationVendor()
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{
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return specVendor;
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}
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/**
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* Returns the version of the specification or null if unknown.
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*/
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public String getSpecificationVersion()
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{
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return specVersion;
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}
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/**
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* Returns true if this Package is sealed.
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*/
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public boolean isSealed()
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{
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return (sealed != null);
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}
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/**
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* Returns true if this Package is sealed and the origin of the classes is
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* the given URL.
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*
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* @param url
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*/
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public boolean isSealed(URL url)
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{
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return url.equals(sealed);
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}
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/**
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* Checks if the version of the specification is higher or at least as high
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* as the desired version.
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* @param version the (minimal) desired version of the specification
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* @exception NumberFormatException when either version or the
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* specification version is not a correctly formatted version number
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* @exception NullPointerException if the supplied version or the
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* Package specification version is null.
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*/
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public boolean isCompatibleWith(String version) throws NumberFormatException
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{
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StringTokenizer versionTokens = new StringTokenizer(version, ".");
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StringTokenizer specTokens = new StringTokenizer(specVersion, ".");
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try
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{
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while (versionTokens.hasMoreElements())
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{
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int vers = Integer.parseInt(versionTokens.nextToken());
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int spec = Integer.parseInt(specTokens.nextToken());
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if (spec < vers)
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return false;
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else if (spec > vers)
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return true;
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// They must be equal, next Token please!
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}
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}
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catch (NoSuchElementException e)
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{
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// this must have been thrown by spec.netToken() so return false
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return false;
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}
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// They must have been exactly the same version.
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// Or the specVersion has more subversions. That is also good.
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return true;
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}
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/**
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* Returns the named package if it is known by the callers class loader.
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* It may return null if the package is unknown, when there is no
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* information on that particular package available or when the callers
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* classloader is null.
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* @param name the name of the desired package
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*/
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public static Package getPackage(String name)
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{
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// Get the caller's classloader
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SecurityManager sm = System.getSecurityManager();
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Class c = sm.getClassContext()[1];
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ClassLoader cl = c.getClassLoader();
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if (cl != null)
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return cl.getPackage(name);
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else
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return null;
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}
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/**
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* Returns all the packages that are known to the callers class loader.
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* It may return an empty array if the classloader of the caller is null.
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*/
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public static Package[] getPackages()
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{
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// Get the caller's classloader
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SecurityManager sm = System.getSecurityManager();
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Class c = sm.getClassContext()[1];
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ClassLoader cl = c.getClassLoader();
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if (cl != null)
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return cl.getPackages();
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else
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return new Package[0];
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}
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/**
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* Returns the hashCode of the name of this package.
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*/
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public int hashCode()
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{
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return name.hashCode();
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}
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/**
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* Returns a string representation of this package name, specification,
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* implementation and class origin if sealed.
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*/
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public String toString()
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{
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return "package: " + name +
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" spec: " + specTitle +
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" version: " + specVersion +
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" vendor: " + specVendor +
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" implementation: " + implTitle +
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" version: " + implVersion +
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" vendor: " + implVendor + " sealed: " + sealed;
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}
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}
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