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 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package java.lang;

import java.lang.annotation.Annotation;

import java.lang.reflect.AnnotatedElement;

import java.net.MalformedURLException;

import java.net.URI;

import java.net.URL;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.Objects;

import jdk.internal.loader.BootLoader;

import jdk.internal.reflect.CallerSensitive;

import jdk.internal.reflect.Reflection;

/**

 * Represents metadata about a run-time package associated with a class loader.

 * Metadata includes annotations, versioning, and sealing.

 * <p>

 * Annotations for the run-time package are read from {@code package-info.class}

 * at the same code source as classes in the run-time package.

 * <p>

 * The set of classes that make up the run-time package may implement a

 * particular specification. The specification title, version, and vendor

 * (indicating the owner/maintainer of the specification) can be provided

 * when the {@code Package} is defined. An application can ask if the

 * {@code Package} is compatible with a particular specification version

 * by using the {@link #isCompatibleWith Package.isCompatibleWith(String)}

 * method. In addition, information about the actual classes that make up the

 * run-time package can be provided when the Package is defined.

 * This information consists of an implementation title, version, and vendor

 * (indicating the supplier of the classes).

 * <p>

 * A {@code Package} may be explicitly defined with

 * the {@link ClassLoader#definePackage(String, String, String, String,

 * String, String, String, URL)} method.

 * The caller supplies the specification and implementation titles, versions, and

 * vendors. The caller also indicates whether the package is

 * {@linkplain java.util.jar.Attributes.Name#SEALED sealed}.

 * If a {@code Package} is not explicitly defined for a run-time package when

 * a class in that run-time package is defined, then a {@code Package} is

 * automatically defined by the class's defining class loader, as follows.

 * <p>

 * A {@code Package} automatically defined for classes in a named module has

 * the following properties:

 * <ul>

 * <li>The name of the package is derived from the {@linkplain Class#getName() binary names}

 *     of the classes. Since classes in a named module must be in a named package,

 *     the derived name is never empty.</li>

 * <li>The package is sealed with the {@linkplain java.lang.module.ModuleReference#location()

 *     module location} as the code source, if known.</li>

 * <li>The specification and implementation titles, versions, and vendors

 *     are unspecified.</li>

 * <li>Any annotations on the package are read from {@code package-info.class}

 *     as specified above.</li>

 * </ul>

 * <p>

 * A {@code Package} automatically defined for classes in an unnamed module

 * has the following properties:

 * <ul>

 * <li>The name of the package is either {@code ""} (for classes in an unnamed package)

 *     or derived from the {@linkplain Class#getName() binary names} of the classes

 *     (for classes in a named package).</li>

 * <li>The package is not sealed.</li>

 * <li>The specification and implementation titles, versions, and vendors

 *     are unspecified.</li>

 * <li>Any annotations on the package are read from {@code package-info.class}

 *     as specified above.</li>

 * </ul>

 *

 * <p>

 * A {@code Package} can be obtained with the {@link Package#getPackage

 * Package.getPackage(String)} and {@link ClassLoader#getDefinedPackage

 * ClassLoader.getDefinedPackage(String)} methods.

 * Every {@code Package} defined by a class loader can be obtained

 * with the {@link Package#getPackages Package.getPackages()} and

 * {@link ClassLoader#getDefinedPackages} methods.

 *

 * @implNote

 * The <a href="ClassLoader.html#builtinLoaders">builtin class loaders</a>

 * do not explicitly define {@code Package} objects for packages in

 * <em>named modules</em>.  Instead those packages are automatically defined

 * and have no specification and implementation versioning information.

 *

 * @jvms 5.3 Run-time package

 * @see <a href="{@docRoot}/../specs/jar/jar.html#package-sealing">

 * The JAR File Specification: Package Sealing</a>

 * @see ClassLoader#definePackage(String, String, String, String, String, String, String, URL)

 *

 * @since 1.2

 * @revised 9

 * @spec JPMS

 */

public class Package extends NamedPackage implements java.lang.reflect.AnnotatedElement {

    /**

     * Return the name of this package.

     *

     * @return  The fully-qualified name of this package as defined in section 6.5.3 of

     *          <cite>The Java&trade; Language Specification</cite>,

     *          for example, {@code java.lang}

     */

    public String getName() {

        return packageName();

    }

    /**

     * Return the title of the specification that this package implements.

     * @return the specification title, {@code null} is returned if it is not known.

     */

    public String getSpecificationTitle() {

        return versionInfo.specTitle;

    }

    /**

     * Returns the version number of the specification

     * that this package implements.

     * This version string must be a sequence of non-negative decimal

     * integers separated by "."'s and may have leading zeros.

     * When version strings are compared the most significant

     * numbers are compared.

     *

     *

     * <p>Specification version numbers use a syntax that consists of non-negative

     * 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:</i>

     * <dd><i>Digits RefinedVersion<sub>opt</sub></i>

     * <dt><i>RefinedVersion:</i>

     * <dd>{@code .} <i>Digits</i>

     * <dd>{@code .} <i>Digits RefinedVersion</i>

     *

     * <dt><i>Digits:</i>

     * <dd><i>Digit</i>

     * <dd><i>Digits</i>

     *

     * <dt><i>Digit:</i>

     * <dd>any character for which {@link Character#isDigit} returns {@code true},

     * e.g. 0, 1, 2, ...

     * </dl>

     * </blockquote>

     *

     * @return the specification version, {@code null} is returned if it is not known.

     */

    public String getSpecificationVersion() {

        return versionInfo.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, {@code null} is returned if it is not known.

     */

    public String getSpecificationVendor() {

        return versionInfo.specVendor;

    }

    /**

     * Return the title of this package.

     * @return the title of the implementation, {@code null} is returned if it is not known.

     */

    public String getImplementationTitle() {

        return versionInfo.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, {@code null} is returned if it is not known.

     */

    public String getImplementationVersion() {

        return versionInfo.implVersion;

    }

    /**

     * Returns the vendor that implemented this package, {@code null}

     * is returned if it is not known.

     * @return the vendor that implemented this package, {@code null}

     * is returned if it is not known.

     *

     * @revised 9

     * @spec JPMS

     */

    public String getImplementationVendor() {

        return versionInfo.implVendor;

    }

    /**

     * Returns true if this package is sealed.

     *

     * @return true if the package is sealed, false otherwise

     */

    public boolean isSealed() {

        return module().isNamed() || versionInfo.sealBase != null;

    }

    /**

     * Returns true if this package is sealed with respect to the specified

     * code source {@code url}.

     *

     * @param url the code source URL

     * @return true if this package is sealed with respect to the given {@code url}

     */

    public boolean isSealed(URL url) {

        Objects.requireNonNull(url);

        URL sealBase = null;

        if (versionInfo != VersionInfo.NULL_VERSION_INFO) {

            sealBase = versionInfo.sealBase;

        } else {

            try {

                URI uri = location();

                sealBase = uri != null ? uri.toURL() : null;

            } catch (MalformedURLException e) {

            }

        }

        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 current version is not known or

     *          the desired or current version is not of the correct dotted form.

     */

    public boolean isCompatibleWith(String desired)

        throws NumberFormatException

    {

        if (versionInfo.specVersion == null || versionInfo.specVersion.length() < 1) {

            throw new NumberFormatException("Empty version string");

        }

        String [] sa = versionInfo.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], 10);

        }

        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], 10);

        }

        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;

    }

    /**

     * Finds a package by name in the caller's class loader and its

     * ancestors.

     * <p>

     * If the caller's class loader defines a {@code Package} of the given name,

     * the {@code Package} is returned. Otherwise, the ancestors of the

     * caller's class loader are searched recursively (parent by parent)

     * for a {@code Package} of the given name.

     * <p>

     * Calling this method is equivalent to calling {@link ClassLoader#getPackage}

     * on a {@code ClassLoader} instance which is the caller's class loader.

     *

     * @param name A package name, such as "{@code java.lang}".

     * @return The {@code Package} of the given name defined by the caller's

     *         class loader or its ancestors, or {@code null} if not found.

     *

     * @throws NullPointerException

     *         if {@code name} is {@code null}.

     *

     * @deprecated

     * If multiple class loaders delegate to each other and define classes

     * with the same package name, and one such loader relies on the lookup

     * behavior of {@code getPackage} to return a {@code Package} from

     * a parent loader, then the properties exposed by the {@code Package}

     * may not be as expected in the rest of the program.

     * For example, the {@code Package} will only expose annotations from the

     * {@code package-info.class} file defined by the parent loader, even if

     * annotations exist in a {@code package-info.class} file defined by

     * a child loader.  A more robust approach is to use the

     * {@link ClassLoader#getDefinedPackage} method which returns

     * a {@code Package} for the specified class loader.

     *

     * @see ClassLoader#getDefinedPackage

     *

     * @revised 9

     * @spec JPMS

     */

    @CallerSensitive

    @Deprecated(since="9")

    @SuppressWarnings("deprecation")

    public static Package getPackage(String name) {

        ClassLoader l = ClassLoader.getClassLoader(Reflection.getCallerClass());

        return l != null ? l.getPackage(name) : BootLoader.getDefinedPackage(name);

    }

    /**

     * Returns all of the {@code Package}s defined by the caller's class loader

     * and its ancestors.  The returned array may contain more than one

     * {@code Package} object of the same package name, each defined by

     * a different class loader in the class loader hierarchy.

     * <p>

     * Calling this method is equivalent to calling {@link ClassLoader#getPackages}

     * on a {@code ClassLoader} instance which is the caller's class loader.

     *

     * @return  The array of {@code Package} objects defined by this

     *          class loader and its ancestors

     *

     * @see ClassLoader#getDefinedPackages

     *

     * @revised 9

     * @spec JPMS

     */

    @CallerSensitive

    public static Package[] getPackages() {

        ClassLoader cl = ClassLoader.getClassLoader(Reflection.getCallerClass());

        return cl != null ? cl.getPackages() : BootLoader.packages().toArray(Package[]::new);

    }

    /**

     * Return the hash code computed from the package name.

     * @return the hash code computed from the package name.

     */

    @Override

    public int hashCode(){

        return packageName().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.

     */

    @Override

    public String toString() {

        String spec = versionInfo.specTitle;

        String ver =  versionInfo.specVersion;

            spec = ", " + spec;

        else

            spec = "";

            ver = ", version " + ver;

        else

            ver = "";

        return "package " + packageName() + spec + ver;

    }

    private Class<?> getPackageInfo() {

        if (packageInfo == null) {

            // find package-info.class defined by loader

            String cn = packageName() + ".package-info";

            Module module = module();

            PrivilegedAction<ClassLoader> pa = module::getClassLoader;

            ClassLoader loader = AccessController.doPrivileged(pa);

            Class<?> c;

            if (loader != null) {

                c = loader.loadClass(module, cn);

            } else {

                c = BootLoader.loadClass(module, cn);

            }

            if (c != null) {

                packageInfo = c;

            } else {

                // 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);

    }

    /**

     * {@inheritDoc}

     * @throws NullPointerException {@inheritDoc}

     * @since 1.5

     */

    @Override

    public boolean isAnnotationPresent(Class<? extends Annotation> annotationClass) {

        return AnnotatedElement.super.isAnnotationPresent(annotationClass);

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     * @since 1.8

     */

    @Override

    public  <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) {

        return getPackageInfo().getAnnotationsByType(annotationClass);

    }

    /**

     * @since 1.5

     */

    public Annotation[] getAnnotations() {

        return getPackageInfo().getAnnotations();

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     * @since 1.8

     */

    @Override

    public <A extends Annotation> A getDeclaredAnnotation(Class<A> annotationClass) {

        return getPackageInfo().getDeclaredAnnotation(annotationClass);

    }

    /**

     * @throws NullPointerException {@inheritDoc}

     * @since 1.8

     */

    @Override

    public <A extends Annotation> A[] getDeclaredAnnotationsByType(Class<A> annotationClass) {

        return getPackageInfo().getDeclaredAnnotationsByType(annotationClass);

    }

    /**

     * @since 1.5

     */

    public Annotation[] getDeclaredAnnotations()  {

        return getPackageInfo().getDeclaredAnnotations();

    }

    /**

     * Construct a package instance for an unnamed module

     * with the specified version information.

     *

     * @apiNote

     * This method should not be called to define a Package for named module.

     *