jdk/src/share/classes/java/lang/Package.java
changeset 2 90ce3da70b43
child 51 6fe31bc95bbc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/lang/Package.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,615 @@
+/*
+ * Copyright 1997-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.lang;
+
+import java.io.InputStream;
+import java.util.Enumeration;
+
+import java.util.StringTokenizer;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.net.URL;
+import java.net.MalformedURLException;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+import java.util.jar.JarInputStream;
+import java.util.jar.Manifest;
+import java.util.jar.Attributes;
+import java.util.jar.Attributes.Name;
+import java.util.jar.JarException;
+import java.util.Map;
+import java.util.HashMap;
+import java.util.Iterator;
+
+import sun.net.www.ParseUtil;
+
+import java.lang.annotation.Annotation;
+
+/**
+ * {@code Package} objects contain version information
+ * about the implementation and specification of a Java package.
+ * This versioning information is retrieved and made available
+ * by the {@link ClassLoader} instance that
+ * loaded the class(es).  Typically, it is stored in the manifest that is
+ * distributed with the classes.
+ *
+ * <p>The set of classes that make up the package may implement a
+ * particular specification and if so the specification title, version number,
+ * and vendor strings identify that specification.
+ * An application can ask if the package is
+ * compatible with a particular version, see the {@link
+ * #isCompatibleWith isCompatibleWith}
+ * method for details.
+ *
+ * <p>Specification version numbers use a syntax that consists of nonnegative
+ * decimal integers separated by periods ".", for example "2.0" or
+ * "1.2.3.4.5.6.7".  This allows an extensible number to be used to represent
+ * major, minor, micro, etc. versions.  The version specification is described
+ * by the following formal grammar:
+ * <blockquote>
+ * <dl>
+ * <dt><i>SpecificationVersion:
+ * <dd>Digits RefinedVersion<sub>opt</sub></i>
+
+ * <p><dt><i>RefinedVersion:</i>
+ * <dd>{@code .} <i>Digits</i>
+ * <dd>{@code .} <i>Digits RefinedVersion</i>
+ *
+ * <p><dt><i>Digits:
+ * <dd>Digit
+ * <dd>Digits</i>
+ *
+ * <p><dt><i>Digit:</i>
+ * <dd>any character for which {@link Character#isDigit} returns {@code true},
+ * e.g. 0, 1, 2, ...
+ * </dl>
+ * </blockquote>
+ *
+ * <p>The implementation title, version, and vendor strings identify an
+ * implementation and are made available conveniently to enable accurate
+ * reporting of the packages involved when a problem occurs. The contents
+ * all three implementation strings are vendor specific. The
+ * implementation version strings have no specified syntax and should
+ * only be compared for equality with desired version identifiers.
+ *
+ * <p>Within each {@code ClassLoader} instance all classes from the same
+ * java package have the same Package object.  The static methods allow a package
+ * to be found by name or the set of all packages known to the current class
+ * loader to be found.
+ *
+ * @see ClassLoader#definePackage
+ */
+public class Package implements java.lang.reflect.AnnotatedElement {
+    /**
+     * Return the name of this package.
+     *
+     * @return  The fully-qualified name of this package as defined in the
+     *          <em>Java Language Specification, Third Edition</em>
+     *          <a href="http://java.sun.com/docs/books/jls/third_edition/html/names.html#6.5.3">
+     *          &sect;6.5.3</a>, for example, {@code java.lang}
+     */
+    public String getName() {
+        return pkgName;
+    }
+
+
+    /**
+     * Return the title of the specification that this package implements.
+     * @return the specification title, null is returned if it is not known.
+     */
+    public String getSpecificationTitle() {
+        return specTitle;
+    }
+
+    /**
+     * Returns the version number of the specification
+     * that this package implements.
+     * This version string must be a sequence of nonnegative decimal
+     * integers separated by "."'s and may have leading zeros.
+     * When version strings are compared the most significant
+     * numbers are compared.
+     * @return the specification version, null is returned if it is not known.
+     */
+    public String getSpecificationVersion() {
+        return specVersion;
+    }
+
+    /**
+     * Return the name of the organization, vendor,
+     * or company that owns and maintains the specification
+     * of the classes that implement this package.
+     * @return the specification vendor, null is returned if it is not known.
+     */
+    public String getSpecificationVendor() {
+        return specVendor;
+    }
+
+    /**
+     * Return the title of this package.
+     * @return the title of the implementation, null is returned if it is not known.
+     */
+    public String getImplementationTitle() {
+        return implTitle;
+    }
+
+    /**
+     * Return the version of this implementation. It consists of any string
+     * assigned by the vendor of this implementation and does
+     * not have any particular syntax specified or expected by the Java
+     * runtime. It may be compared for equality with other
+     * package version strings used for this implementation
+     * by this vendor for this package.
+     * @return the version of the implementation, null is returned if it is not known.
+     */
+    public String getImplementationVersion() {
+        return implVersion;
+    }
+
+    /**
+     * Returns the name of the organization,
+     * vendor or company that provided this implementation.
+     * @return the vendor that implemented this package..
+     */
+    public String getImplementationVendor() {
+        return implVendor;
+    }
+
+    /**
+     * Returns true if this package is sealed.
+     *
+     * @return true if the package is sealed, false otherwise
+     */
+    public boolean isSealed() {
+        return sealBase != null;
+    }
+
+    /**
+     * Returns true if this package is sealed with respect to the specified
+     * code source url.
+     *
+     * @param url the code source url
+     * @return true if this package is sealed with respect to url
+     */
+    public boolean isSealed(URL url) {
+        return url.equals(sealBase);
+    }
+
+    /**
+     * Compare this package's specification version with a
+     * desired version. It returns true if
+     * this packages specification version number is greater than or equal
+     * to the desired version number. <p>
+     *
+     * Version numbers are compared by sequentially comparing corresponding
+     * components of the desired and specification strings.
+     * Each component is converted as a decimal integer and the values
+     * compared.
+     * If the specification value is greater than the desired
+     * value true is returned. If the value is less false is returned.
+     * If the values are equal the period is skipped and the next pair of
+     * components is compared.
+     *
+     * @param desired the version string of the desired version.
+     * @return true if this package's version number is greater
+     *          than or equal to the desired version number
+     *
+     * @exception NumberFormatException if the desired or current version
+     *          is not of the correct dotted form.
+     */
+    public boolean isCompatibleWith(String desired)
+        throws NumberFormatException
+    {
+        if (specVersion == null || specVersion.length() < 1) {
+            throw new NumberFormatException("Empty version string");
+        }
+
+        String [] sa = specVersion.split("\\.", -1);
+        int [] si = new int[sa.length];
+        for (int i = 0; i < sa.length; i++) {
+            si[i] = Integer.parseInt(sa[i]);
+            if (si[i] < 0)
+                throw NumberFormatException.forInputString("" + si[i]);
+        }
+
+        String [] da = desired.split("\\.", -1);
+        int [] di = new int[da.length];
+        for (int i = 0; i < da.length; i++) {
+            di[i] = Integer.parseInt(da[i]);
+            if (di[i] < 0)
+                throw NumberFormatException.forInputString("" + di[i]);
+        }
+
+        int len = Math.max(di.length, si.length);
+        for (int i = 0; i < len; i++) {
+            int d = (i < di.length ? di[i] : 0);
+            int s = (i < si.length ? si[i] : 0);
+            if (s < d)
+                return false;
+            if (s > d)
+                return true;
+        }
+        return true;
+    }
+
+    /**
+     * Find a package by name in the callers {@code ClassLoader} instance.
+     * The callers {@code ClassLoader} instance is used to find the package
+     * instance corresponding to the named class. If the callers
+     * {@code ClassLoader} instance is null then the set of packages loaded
+     * by the system {@code ClassLoader} instance is searched to find the
+     * named package. <p>
+     *
+     * Packages have attributes for versions and specifications only if the class
+     * loader created the package instance with the appropriate attributes. Typically,
+     * those attributes are defined in the manifests that accompany the classes.
+     *
+     * @param name a package name, for example, java.lang.
+     * @return the package of the requested name. It may be null if no package
+     *          information is available from the archive or codebase.
+     */
+    public static Package getPackage(String name) {
+        ClassLoader l = ClassLoader.getCallerClassLoader();
+        if (l != null) {
+            return l.getPackage(name);
+        } else {
+            return getSystemPackage(name);
+        }
+    }
+
+    /**
+     * Get all the packages currently known for the caller's {@code ClassLoader}
+     * instance.  Those packages correspond to classes loaded via or accessible by
+     * name to that {@code ClassLoader} instance.  If the caller's
+     * {@code ClassLoader} instance is the bootstrap {@code ClassLoader}
+     * instance, which may be represented by {@code null} in some implementations,
+     * only packages corresponding to classes loaded by the bootstrap
+     * {@code ClassLoader} instance will be returned.
+     *
+     * @return a new array of packages known to the callers {@code ClassLoader}
+     * instance.  An zero length array is returned if none are known.
+     */
+    public static Package[] getPackages() {
+        ClassLoader l = ClassLoader.getCallerClassLoader();
+        if (l != null) {
+            return l.getPackages();
+        } else {
+            return getSystemPackages();
+        }
+    }
+
+    /**
+     * Get the package for the specified class.
+     * The class's class loader is used to find the package instance
+     * corresponding to the specified class. If the class loader
+     * is the bootstrap class loader, which may be represented by
+     * {@code null} in some implementations, then the set of packages
+     * loaded by the bootstrap class loader is searched to find the package.
+     * <p>
+     * Packages have attributes for versions and specifications only
+     * if the class loader created the package
+     * instance with the appropriate attributes. Typically those
+     * attributes are defined in the manifests that accompany
+     * the classes.
+     *
+     * @param class the class to get the package of.
+     * @return the package of the class. It may be null if no package
+     *          information is available from the archive or codebase.  */
+    static Package getPackage(Class c) {
+        String name = c.getName();
+        int i = name.lastIndexOf('.');
+        if (i != -1) {
+            name = name.substring(0, i);
+            ClassLoader cl = c.getClassLoader();
+            if (cl != null) {
+                return cl.getPackage(name);
+            } else {
+                return getSystemPackage(name);
+            }
+        } else {
+            return null;
+        }
+    }
+
+    /**
+     * Return the hash code computed from the package name.
+     * @return the hash code computed from the package name.
+     */
+    public int hashCode(){
+        return pkgName.hashCode();
+    }
+
+    /**
+     * Returns the string representation of this Package.
+     * Its value is the string "package " and the package name.
+     * If the package title is defined it is appended.
+     * If the package version is defined it is appended.
+     * @return the string representation of the package.
+     */
+    public String toString() {
+        String spec = specTitle;
+        String ver =  specVersion;
+        if (spec != null && spec.length() > 0)
+            spec = ", " + spec;
+        else
+            spec = "";
+        if (ver != null && ver.length() > 0)
+            ver = ", version " + ver;
+        else
+            ver = "";
+        return "package " + pkgName + spec + ver;
+    }
+
+    private Class<?> getPackageInfo() {
+        if (packageInfo == null) {
+            try {
+                packageInfo = Class.forName(pkgName + ".package-info", false, loader);
+            } catch (ClassNotFoundException ex) {
+                // store a proxy for the package info that has no annotations
+                class PackageInfoProxy {}
+                packageInfo = PackageInfoProxy.class;
+            }
+        }
+        return packageInfo;
+    }
+
+    /**
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.5
+     */
+    public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
+        return getPackageInfo().getAnnotation(annotationClass);
+    }
+
+    /**
+     * @throws NullPointerException {@inheritDoc}
+     * @since 1.5
+     */
+    public boolean isAnnotationPresent(
+        Class<? extends Annotation> annotationClass) {
+        return getPackageInfo().isAnnotationPresent(annotationClass);
+    }
+
+    /**
+     * @since 1.5
+     */
+    public Annotation[] getAnnotations() {
+        return getPackageInfo().getAnnotations();
+    }
+
+    /**
+     * @since 1.5
+     */
+    public Annotation[] getDeclaredAnnotations()  {
+        return getPackageInfo().getDeclaredAnnotations();
+    }
+
+    /**
+     * Construct a package instance with the specified version
+     * information.
+     * @param pkgName the name of the package
+     * @param spectitle the title of the specification
+     * @param specversion the version of the specification
+     * @param specvendor the organization that maintains the specification
+     * @param impltitle the title of the implementation
+     * @param implversion the version of the implementation
+     * @param implvendor the organization that maintains the implementation
+     * @return a new package for containing the specified information.
+     */
+    Package(String name,
+            String spectitle, String specversion, String specvendor,
+            String impltitle, String implversion, String implvendor,
+            URL sealbase, ClassLoader loader)
+    {
+        pkgName = name;
+        implTitle = impltitle;
+        implVersion = implversion;
+        implVendor = implvendor;
+        specTitle = spectitle;
+        specVersion = specversion;
+        specVendor = specvendor;
+        sealBase = sealbase;
+        this.loader = loader;
+    }
+
+    /*
+     * Construct a package using the attributes from the specified manifest.
+     *
+     * @param name the package name
+     * @param man the optional manifest for the package
+     * @param url the optional code source url for the package
+     */
+    private Package(String name, Manifest man, URL url, ClassLoader loader) {
+        String path = name.replace('.', '/').concat("/");
+        String sealed = null;
+        String specTitle= null;
+        String specVersion= null;
+        String specVendor= null;
+        String implTitle= null;
+        String implVersion= null;
+        String implVendor= null;
+        URL sealBase= null;
+        Attributes attr = man.getAttributes(path);
+        if (attr != null) {
+            specTitle   = attr.getValue(Name.SPECIFICATION_TITLE);
+            specVersion = attr.getValue(Name.SPECIFICATION_VERSION);
+            specVendor  = attr.getValue(Name.SPECIFICATION_VENDOR);
+            implTitle   = attr.getValue(Name.IMPLEMENTATION_TITLE);
+            implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION);
+            implVendor  = attr.getValue(Name.IMPLEMENTATION_VENDOR);
+            sealed      = attr.getValue(Name.SEALED);
+        }
+        attr = man.getMainAttributes();
+        if (attr != null) {
+            if (specTitle == null) {
+                specTitle = attr.getValue(Name.SPECIFICATION_TITLE);
+            }
+            if (specVersion == null) {
+                specVersion = attr.getValue(Name.SPECIFICATION_VERSION);
+            }
+            if (specVendor == null) {
+                specVendor = attr.getValue(Name.SPECIFICATION_VENDOR);
+            }
+            if (implTitle == null) {
+                implTitle = attr.getValue(Name.IMPLEMENTATION_TITLE);
+            }
+            if (implVersion == null) {
+                implVersion = attr.getValue(Name.IMPLEMENTATION_VERSION);
+            }
+            if (implVendor == null) {
+                implVendor = attr.getValue(Name.IMPLEMENTATION_VENDOR);
+            }
+            if (sealed == null) {
+                sealed = attr.getValue(Name.SEALED);
+            }
+        }
+        if ("true".equalsIgnoreCase(sealed)) {
+            sealBase = url;
+        }
+        pkgName = name;
+        this.specTitle = specTitle;
+        this.specVersion = specVersion;
+        this.specVendor = specVendor;
+        this.implTitle = implTitle;
+        this.implVersion = implVersion;
+        this.implVendor = implVendor;
+        this.sealBase = sealBase;
+        this.loader = loader;
+    }
+
+    /*
+     * Returns the loaded system package for the specified name.
+     */
+    static Package getSystemPackage(String name) {
+        synchronized (pkgs) {
+            Package pkg = (Package)pkgs.get(name);
+            if (pkg == null) {
+                name = name.replace('.', '/').concat("/");
+                String fn = getSystemPackage0(name);
+                if (fn != null) {
+                    pkg = defineSystemPackage(name, fn);
+                }
+            }
+            return pkg;
+        }
+    }
+
+    /*
+     * Return an array of loaded system packages.
+     */
+    static Package[] getSystemPackages() {
+        // First, update the system package map with new package names
+        String[] names = getSystemPackages0();
+        synchronized (pkgs) {
+            for (int i = 0; i < names.length; i++) {
+                defineSystemPackage(names[i], getSystemPackage0(names[i]));
+            }
+            return (Package[])pkgs.values().toArray(new Package[pkgs.size()]);
+        }
+    }
+
+    private static Package defineSystemPackage(final String iname,
+                                               final String fn)
+    {
+        return (Package) AccessController.doPrivileged(new PrivilegedAction() {
+            public Object run() {
+                String name = iname;
+                // Get the cached code source url for the file name
+                URL url = (URL)urls.get(fn);
+                if (url == null) {
+                    // URL not found, so create one
+                    File file = new File(fn);
+                    try {
+                        url = ParseUtil.fileToEncodedURL(file);
+                    } catch (MalformedURLException e) {
+                    }
+                    if (url != null) {
+                        urls.put(fn, url);
+                        // If loading a JAR file, then also cache the manifest
+                        if (file.isFile()) {
+                            mans.put(fn, loadManifest(fn));
+                        }
+                    }
+                }
+                // Convert to "."-separated package name
+                name = name.substring(0, name.length() - 1).replace('/', '.');
+                Package pkg;
+                Manifest man = (Manifest)mans.get(fn);
+                if (man != null) {
+                    pkg = new Package(name, man, url, null);
+                } else {
+                    pkg = new Package(name, null, null, null,
+                                      null, null, null, null, null);
+                }
+                pkgs.put(name, pkg);
+                return pkg;
+            }
+        });
+    }
+
+    /*
+     * Returns the Manifest for the specified JAR file name.
+     */
+    private static Manifest loadManifest(String fn) {
+        try {
+            FileInputStream fis = new FileInputStream(fn);
+            JarInputStream jis = new JarInputStream(fis, false);
+            Manifest man = jis.getManifest();
+            jis.close();
+            return man;
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    // The map of loaded system packages
+    private static Map pkgs = new HashMap(31);
+
+    // Maps each directory or zip file name to its corresponding url
+    private static Map urls = new HashMap(10);
+
+    // Maps each code source url for a jar file to its manifest
+    private static Map mans = new HashMap(10);
+
+    private static native String getSystemPackage0(String name);
+    private static native String[] getSystemPackages0();
+
+    /*
+     * Private storage for the package name and attributes.
+     */
+    private final String pkgName;
+    private final String specTitle;
+    private final String specVersion;
+    private final String specVendor;
+    private final String implTitle;
+    private final String implVersion;
+    private final String implVendor;
+    private final URL sealBase;
+    private transient final ClassLoader loader;
+    private transient Class packageInfo;
+}