/*

 * Copyright (c) 1997, 2013, 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.reflect.AnnotatedElement;

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 sun.reflect.CallerSensitive;

import sun.reflect.Reflection;

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>

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

 * <dd>{@code .} <i>Digits RefinedVersion</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 section 6.5.3 of

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

     *          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.

     */

    @CallerSensitive

    public static Package getPackage(String name) {

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

        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.

     */

    @CallerSensitive

    public static Package[] getPackages() {

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

        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 c 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);

    }

    /**

     * {@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 with the specified version

     * information.

     * @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

     */

    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);

            }

        }