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	/*
	* Copyright (c) 1997, 2021, 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,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	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 {@code 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 Creation and Loading
	* @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
	*/
	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 {@jls 6.5.3} of
	* <cite>The Java 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
	*/
	public String getImplementationVendor() {
	return versionInfo.implVendor;
	}

	/**
	* Returns true if this package is sealed.
	*
	* @apiNote
	* <a href="{@docRoot}/../specs/jar/jar.html#package-sealing">Package sealing</a>
	* has no relationship with {@linkplain Class#isSealed() sealed classes or interfaces}.
	* Package sealing is specific to JAR files defined for classes in an unnamed module.
	* See the {@link Package Package} class specification for details
	* how a {@code Package} is defined as sealed package.
	*
	* @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}.
	*
	* @apiNote
	* <a href="{@docRoot}/../specs/jar/jar.html#package-sealing">Package sealing</a>
	* has no relationship with {@linkplain Class#isSealed() sealed classes or interfaces}.
	* Package sealing is specific to JAR files defined for classes in an unnamed module.
	* See the {@link Package Package} class specification for details
	* how a {@code Package} is defined as sealed package.
	*
	* @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
	*
	* @throws 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
	*/
	@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
	*/
	@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;
	if (spec != null && !spec.isEmpty())
	spec = ", " + spec;
	else
	spec = "";
	if (ver != null && !ver.isEmpty())
	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;
	@SuppressWarnings("removal")
	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;
	}

	/**
	* {@inheritDoc}
	* <p>Note that any annotation returned by this method is a
	* declaration annotation.
	*
	* @throws NullPointerException {@inheritDoc}
	* @since 1.5
	*/
	@Override
	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);
	}

	/**
	* {@inheritDoc}
	* <p>Note that any annotations returned by this method are
	* declaration annotations.
	*
	* @throws NullPointerException {@inheritDoc}
	* @since 1.8
	*/
	@Override
	public <A extends Annotation> A[] getAnnotationsByType(Class<A> annotationClass) {
	return getPackageInfo().getAnnotationsByType(annotationClass);
	}

	/**
	* {@inheritDoc}
	* <p>Note that any annotations returned by this method are
	* declaration annotations.
	* @since 1.5
	*/
	@Override
	public Annotation[] getAnnotations() {
	return getPackageInfo().getAnnotations();
	}

	/**
	* {@inheritDoc}
	* <p>Note that any annotation returned by this method is a
	* declaration annotation.
	*
	* @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);
	}

	/**
	* {@inheritDoc}
	* <p>Note that any annotations returned by this method are
	* declaration annotations.
	* @since 1.5
	*/
	@Override
	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.
	*
	* @param name 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
	* @param sealbase code source where this Package comes from
	* @param loader defining class loader
	*/
	Package(String name,
	String spectitle, String specversion, String specvendor,
	String impltitle, String implversion, String implvendor,
	URL sealbase, ClassLoader loader)
	{
	super(Objects.requireNonNull(name),
	loader != null ? loader.getUnnamedModule()
	: BootLoader.getUnnamedModule());

	this.versionInfo = VersionInfo.getInstance(spectitle, specversion,
	specvendor, impltitle,
	implversion, implvendor,
	sealbase);
	}

	Package(String name, Module module) {
	super(name, module);
	this.versionInfo = VersionInfo.NULL_VERSION_INFO;
	}

	/*
	* Versioning information. Only for packages in unnamed modules.
	*/
	static class VersionInfo {
	static final VersionInfo NULL_VERSION_INFO
	= new VersionInfo(null, null, null, null, null, null, null);

	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;

	static VersionInfo getInstance(String spectitle, String specversion,
	String specvendor, String impltitle,
	String implversion, String implvendor,
	URL sealbase) {
	if (spectitle == null && specversion == null &&
	specvendor == null && impltitle == null &&
	implversion == null && implvendor == null &&
	sealbase == null) {
	return NULL_VERSION_INFO;
	}
	return new VersionInfo(spectitle, specversion, specvendor,
	impltitle, implversion, implvendor,
	sealbase);
	}

	private VersionInfo(String spectitle, String specversion,
	String specvendor, String impltitle,
	String implversion, String implvendor,
	URL sealbase)
	{
	this.implTitle = impltitle;
	this.implVersion = implversion;
	this.implVendor = implvendor;
	this.specTitle = spectitle;
	this.specVersion = specversion;
	this.specVendor = specvendor;
	this.sealBase = sealbase;
	}
	}

	private final VersionInfo versionInfo;
	private Class<?> packageInfo;
	}

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