/*

 * Copyright (c) 2003, 2015, 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 javax.xml.bind;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UnsupportedEncodingException;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.net.URL;

import java.security.AccessController;

import java.util.Map;

import java.util.Properties;

import java.util.StringTokenizer;

import java.util.logging.ConsoleHandler;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 * This class is package private and therefore is not exposed as part of the

 * JAXB API.

 *

 * This code is designed to implement the JAXB 1.0 spec pluggability feature

 *

 * @author <ul><li>Ryan Shoemaker, Sun Microsystems, Inc.</li></ul>

 * @see JAXBContext

 */

class ContextFinder {

    /**

     * When JAXB is in J2SE, rt.jar has to have a JAXB implementation.

     * However, rt.jar cannot have META-INF/services/javax.xml.bind.JAXBContext

     * because if it has, it will take precedence over any file that applications have

     * in their jar files.

     *

     * <p>

     * When the user bundles his own JAXB implementation, we'd like to use it, and we

     * want the platform default to be used only when there's no other JAXB provider.

     *

     * <p>

     * For this reason, we have to hard-code the class name into the API.

     */

    private static final String PLATFORM_DEFAULT_FACTORY_CLASS = "com.sun.xml.internal.bind.v2.ContextFactory";

    // previous value of JAXBContext.JAXB_CONTEXT_FACTORY, using also this to ensure backwards compatibility

    private static final String JAXB_CONTEXT_FACTORY_DEPRECATED = "javax.xml.bind.context.factory";

    private static final Logger logger;

    static {

        logger = Logger.getLogger("javax.xml.bind");

        try {

            if (AccessController.doPrivileged(new GetPropertyAction("jaxb.debug")) != null) {

                // disconnect the logger from a bigger framework (if any)

                // and take the matters into our own hands

                logger.setUseParentHandlers(false);

                logger.setLevel(Level.ALL);

                ConsoleHandler handler = new ConsoleHandler();

                handler.setLevel(Level.ALL);

                logger.addHandler(handler);

            } else {

                // don't change the setting of this logger

                // to honor what other frameworks

                // have done on configurations.

            }

        } catch (Throwable t) {

            // just to be extra safe. in particular System.getProperty may throw

            // SecurityException.

        }

    }

    private static ServiceLoaderUtil.ExceptionHandler<JAXBException> EXCEPTION_HANDLER =

            new ServiceLoaderUtil.ExceptionHandler<JAXBException>() {

                @Override

                public JAXBException createException(Throwable throwable, String message) {

                    return new JAXBException(message, throwable);

                }

            };

    /**

     * If the {@link InvocationTargetException} wraps an exception that shouldn't be wrapped,

     * throw the wrapped exception.

     */

    private static void handleInvocationTargetException(InvocationTargetException x) throws JAXBException {

        Throwable t = x.getTargetException();

        if (t != null) {

            if (t instanceof JAXBException)

                // one of our exceptions, just re-throw

                throw (JAXBException) t;

            if (t instanceof RuntimeException)

                // avoid wrapping exceptions unnecessarily

                throw (RuntimeException) t;

            if (t instanceof Error)

                throw (Error) t;

        }

    }

    /**

     * Determine if two types (JAXBContext in this case) will generate a ClassCastException.

     *

     * For example, (targetType)originalType

     *

     * @param originalType

     *          The Class object of the type being cast

     * @param targetType

     *          The Class object of the type that is being cast to

     * @return JAXBException to be thrown.

     */

    private static JAXBException handleClassCastException(Class originalType, Class targetType) {

        final URL targetTypeURL = which(targetType);

        return new JAXBException(Messages.format(Messages.ILLEGAL_CAST,

                // we don't care where the impl class is, we want to know where JAXBContext lives in the impl

                // class' ClassLoader

                getClassClassLoader(originalType).getResource("javax/xml/bind/JAXBContext.class"),

                targetTypeURL));

    }

    /**

     * Create an instance of a class using the specified ClassLoader

     */

    static JAXBContext newInstance(String contextPath,

                                   String className,

                                   ClassLoader classLoader,

                                   Map properties) throws JAXBException {

        try {

            Class spFactory = ServiceLoaderUtil.safeLoadClass(className, PLATFORM_DEFAULT_FACTORY_CLASS, classLoader);

            return newInstance(contextPath, spFactory, classLoader, properties);

        } catch (ClassNotFoundException x) {

            throw new JAXBException(Messages.format(Messages.PROVIDER_NOT_FOUND, className), x);

        } catch (RuntimeException x) {

            // avoid wrapping RuntimeException to JAXBException,

            // because it indicates a bug in this code.

            throw x;

        } catch (Exception x) {

            // can't catch JAXBException because the method is hidden behind

            // reflection.  Root element collisions detected in the call to

            // createContext() are reported as JAXBExceptions - just re-throw it

            // some other type of exception - just wrap it

            throw new JAXBException(Messages.format(Messages.COULD_NOT_INSTANTIATE, className, x), x);

        }

    }

    static JAXBContext newInstance(String contextPath,

                                   Class spFactory,

                                   ClassLoader classLoader,

                                   Map properties) throws JAXBException {

        try {

            /*

             * javax.xml.bind.context.factory points to a class which has a

             * static method called 'createContext' that

             * returns a javax.xml.JAXBContext.

             */

            Object context = null;

            // first check the method that takes Map as the third parameter.

            // this is added in 2.0.

            try {

                Method m = spFactory.getMethod("createContext", String.class, ClassLoader.class, Map.class);

                // any failure in invoking this method would be considered fatal

                context = m.invoke(null, contextPath, classLoader, properties);

            } catch (NoSuchMethodException e) {

                // it's not an error for the provider not to have this method.

            }

            if (context == null) {

                // try the old method that doesn't take properties. compatible with 1.0.

                // it is an error for an implementation not to have both forms of the createContext method.

                Method m = spFactory.getMethod("createContext", String.class, ClassLoader.class);

                // any failure in invoking this method would be considered fatal

                context = m.invoke(null, contextPath, classLoader);

            }

            if (!(context instanceof JAXBContext)) {

                // the cast would fail, so generate an exception with a nice message

                throw handleClassCastException(context.getClass(), JAXBContext.class);

            }

            return (JAXBContext) context;

        } catch (InvocationTargetException x) {

            handleInvocationTargetException(x);

            // for other exceptions, wrap the internal target exception

            // with a JAXBException

            Throwable e = x;

            if (x.getTargetException() != null)

                e = x.getTargetException();

            throw new JAXBException(Messages.format(Messages.COULD_NOT_INSTANTIATE, spFactory, e), e);

        } catch (RuntimeException x) {

            // avoid wrapping RuntimeException to JAXBException,

            // because it indicates a bug in this code.

            throw x;

        } catch (Exception x) {

            // can't catch JAXBException because the method is hidden behind

            // reflection.  Root element collisions detected in the call to

            // createContext() are reported as JAXBExceptions - just re-throw it

            // some other type of exception - just wrap it

            throw new JAXBException(Messages.format(Messages.COULD_NOT_INSTANTIATE, spFactory, x), x);

        }

    }

    /**

     * Create an instance of a class using the thread context ClassLoader

     */

    static JAXBContext newInstance(Class[] classes, Map properties, String className) throws JAXBException {

        Class spi;

        try {

            spi = ServiceLoaderUtil.safeLoadClass(className, PLATFORM_DEFAULT_FACTORY_CLASS, getContextClassLoader());

        } catch (ClassNotFoundException e) {

            throw new JAXBException(e);

        }

        if (logger.isLoggable(Level.FINE)) {

            // extra check to avoid costly which operation if not logged

            logger.log(Level.FINE, "loaded {0} from {1}", new Object[]{className, which(spi)});

        }

        return newInstance(classes, properties, spi);

    }

    static JAXBContext newInstance(Class[] classes,

                                   Map properties,

                                   Class spFactory) throws JAXBException {

        try {

            Method m = spFactory.getMethod("createContext", Class[].class, Map.class);

            Object context = m.invoke(null, classes, properties);

            if (!(context instanceof JAXBContext)) {

                // the cast would fail, so generate an exception with a nice message

                throw handleClassCastException(context.getClass(), JAXBContext.class);

            }

            return (JAXBContext) context;

        } catch (NoSuchMethodException | IllegalAccessException e) {

            throw new JAXBException(e);

        } catch (InvocationTargetException e) {

            handleInvocationTargetException(e);

            Throwable x = e;

            if (e.getTargetException() != null)

                x = e.getTargetException();

            throw new JAXBException(x);

        }

    }

    static JAXBContext find(String factoryId,

                            String contextPath,

                            ClassLoader classLoader,

                            Map properties) throws JAXBException {

        StringTokenizer packages = new StringTokenizer(contextPath, ":");

        if (!packages.hasMoreTokens()) {

            // no context is specified

            throw new JAXBException(Messages.format(Messages.NO_PACKAGE_IN_CONTEXTPATH));

        }

        // search for jaxb.properties in the class loader of each class first

        logger.fine("Searching jaxb.properties");

        while (packages.hasMoreTokens()) {

            // com.acme.foo - > com/acme/foo/jaxb.properties

            String factoryClassName =

                    classNameFromPackageProperties(

                        classLoader,

                        packages.nextToken(":").replace('.', '/'),

                        factoryId,

                        JAXB_CONTEXT_FACTORY_DEPRECATED);

            if (factoryClassName != null) {

                return newInstance(contextPath, factoryClassName, classLoader, properties);

            }

        }

        String factoryName = classNameFromSystemProperties();

        if (factoryName != null) return newInstance(contextPath, factoryName, classLoader, properties);

        JAXBContextFactory obj = ServiceLoaderUtil.firstByServiceLoader(

                JAXBContextFactory.class, logger, EXCEPTION_HANDLER);

        if (obj != null) return obj.createContext(contextPath, classLoader, properties);

        // to ensure backwards compatibility

        factoryName = firstByServiceLoaderDeprecated(JAXBContext.class, classLoader);

        if (factoryName != null) return newInstance(contextPath, factoryName, classLoader, properties);

        Class ctxFactory = (Class) ServiceLoaderUtil.lookupUsingOSGiServiceLoader(

                "javax.xml.bind.JAXBContext", logger);

        if (ctxFactory != null) {

            return newInstance(contextPath, ctxFactory, classLoader, properties);

        }

        // else no provider found

        logger.fine("Trying to create the platform default provider");

        return newInstance(contextPath, PLATFORM_DEFAULT_FACTORY_CLASS, classLoader, properties);

    }

    static JAXBContext find(Class<?>[] classes, Map<String, ?> properties) throws JAXBException {

        // search for jaxb.properties in the class loader of each class first

        logger.fine("Searching jaxb.properties");

        for (final Class c : classes) {

            // this classloader is used only to load jaxb.properties, so doing this should be safe.

            // this is possible for primitives, arrays, and classes that are

            // loaded by poorly implemented ClassLoaders

            if (c.getPackage() == null) continue;

            // TODO: do we want to optimize away searching the same package?  org.Foo, org.Bar, com.Baz

            // classes from the same package might come from different class loades, so it might be a bad idea

            // TODO: it's easier to look things up from the class

            // c.getResourceAsStream("jaxb.properties");

            String factoryClassName =

                    classNameFromPackageProperties(

                            getClassClassLoader(c),

                            c.getPackage().getName().replace('.', '/'),

                            JAXBContext.JAXB_CONTEXT_FACTORY, JAXB_CONTEXT_FACTORY_DEPRECATED);

            if (factoryClassName != null) return newInstance(classes, properties, factoryClassName);

        }

        String factoryClassName = classNameFromSystemProperties();

        if (factoryClassName != null) return newInstance(classes, properties, factoryClassName);

        JAXBContextFactory factory =

                ServiceLoaderUtil.firstByServiceLoader(JAXBContextFactory.class, logger, EXCEPTION_HANDLER);

        if (factory != null) return factory.createContext(classes, properties);

        // to ensure backwards compatibility

        String className = firstByServiceLoaderDeprecated(JAXBContext.class, getContextClassLoader());

        if (className != null) return newInstance(classes, properties, className);

        logger.fine("Trying to create the platform default provider");

        Class ctxFactoryClass =

                (Class) ServiceLoaderUtil.lookupUsingOSGiServiceLoader("javax.xml.bind.JAXBContext", logger);

        if (ctxFactoryClass != null) {

            return newInstance(classes, properties, ctxFactoryClass);

        }

        // else no provider found

        logger.fine("Trying to create the platform default provider");

        return newInstance(classes, properties, PLATFORM_DEFAULT_FACTORY_CLASS);

    }

    /**

     * first factoryId should be the preffered one,

     * more of those can be provided to support backwards compatibility

     */

    private static String classNameFromPackageProperties(ClassLoader classLoader,

                                                         String packageName,

                                                         String ... factoryIds) throws JAXBException {

        String resourceName = packageName + "/jaxb.properties";

        logger.log(Level.FINE, "Trying to locate {0}", resourceName);

        Properties props = loadJAXBProperties(classLoader, resourceName);

        if (props != null) {

            for(String factoryId : factoryIds) {

                if (props.containsKey(factoryId)) {

                    return props.getProperty(factoryId);

                }

            }

            throw new JAXBException(Messages.format(Messages.MISSING_PROPERTY, packageName, factoryIds[0]));

        }

        return null;

    }

    private static String classNameFromSystemProperties() throws JAXBException {

        String factoryClassName = getSystemProperty(JAXBContext.JAXB_CONTEXT_FACTORY);

        if (factoryClassName != null) {

            return factoryClassName;

        }

        // leave this here to assure compatibility

        factoryClassName = getDeprecatedSystemProperty(JAXB_CONTEXT_FACTORY_DEPRECATED);

        if (factoryClassName != null) {

            return factoryClassName;

        }

        // leave this here to assure compatibility

        factoryClassName = getDeprecatedSystemProperty(JAXBContext.class.getName());

        if (factoryClassName != null) {

            return factoryClassName;

        }

        return null;

    }

    private static String getDeprecatedSystemProperty(String property) {

        String value = getSystemProperty(property);

        if (value != null) {

            logger.log(Level.WARNING, "Using non-standard property: {0}. Property {1} should be used instead.",

                    new Object[] {property, JAXBContext.JAXB_CONTEXT_FACTORY});

        }

        return value;

    }

    private static String getSystemProperty(String property) {

        logger.log(Level.FINE, "Checking system property {0}", property);

        String value = AccessController.doPrivileged(new GetPropertyAction(property));

        if (value != null) {

            logger.log(Level.FINE, "  found {0}", value);

        } else {

            logger.log(Level.FINE, "  not found");

        }

        return value;

    }

    private static Properties loadJAXBProperties(ClassLoader classLoader,

                                                 String propFileName) throws JAXBException {

        Properties props = null;

        try {

            URL url;

            if (classLoader == null)

                url = ClassLoader.getSystemResource(propFileName);

            else

                url = classLoader.getResource(propFileName);

            if (url != null) {

                logger.log(Level.FINE, "loading props from {0}", url);

                props = new Properties();

                InputStream is = url.openStream();

                props.load(is);

                is.close();

            }

        } catch (IOException ioe) {

            logger.log(Level.FINE, "Unable to load " + propFileName, ioe);

            throw new JAXBException(ioe.toString(), ioe);

        }

        return props;

    }

    /**

     * Search the given ClassLoader for an instance of the specified class and

     * return a string representation of the URL that points to the resource.

     *

     * @param clazz

     *          The class to search for

     * @param loader

     *          The ClassLoader to search.  If this parameter is null, then the

     *          system class loader will be searched

     * @return

     *          the URL for the class or null if it wasn't found

     */

    static URL which(Class clazz, ClassLoader loader) {

        String classnameAsResource = clazz.getName().replace('.', '/') + ".class";

        if (loader == null) {

            loader = getSystemClassLoader();

        }

        return loader.getResource(classnameAsResource);

    }

    /**

     * Get the URL for the Class from it's ClassLoader.

     *

     * Convenience method for {@link #which(Class, ClassLoader)}.

     *

     * Equivalent to calling: which(clazz, clazz.getClassLoader())

     *

     * @param clazz

     *          The class to search for

     * @return

     *          the URL for the class or null if it wasn't found

     */

    static URL which(Class clazz) {

        return which(clazz, getClassClassLoader(clazz));

    }