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	/*
	* Copyright (c) 1999, 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 com.sun.naming.internal;

	import java.io.InputStream;
	import java.io.IOException;
	import java.lang.ref.WeakReference;
	import java.lang.reflect.Method;
	import java.lang.reflect.InvocationTargetException;
	import java.util.HashMap;
	import java.util.Hashtable;
	import java.util.Map;
	import java.util.Properties;
	import java.util.StringTokenizer;
	import java.util.List;
	import java.util.ArrayList;
	import java.util.WeakHashMap;

	import javax.naming.*;

	/**
	* The ResourceManager class facilitates the reading of JNDI resource files.
	*
	* @author Rosanna Lee
	* @author Scott Seligman
	*/

	public final class ResourceManager {

	/*
	* Name of provider resource files (without the package-name prefix.)
	*/
	private static final String PROVIDER_RESOURCE_FILE_NAME =
	"jndiprovider.properties";

	/*
	* Name of application resource files.
	*/
	private static final String APP_RESOURCE_FILE_NAME = "jndi.properties";

	/*
	* Name of properties file in <java.home>/lib.
	*/
	private static final String JRELIB_PROPERTY_FILE_NAME = "jndi.properties";

	/*
	* Internal environment property, that when set to "true", disables
	* application resource files lookup to prevent recursion issues
	* when validating signed JARs.
	*/
	private static final String DISABLE_APP_RESOURCE_FILES =
	"com.sun.naming.disable.app.resource.files";

	/*
	* The standard JNDI properties that specify colon-separated lists.
	*/
	private static final String[] listProperties = {
	Context.OBJECT_FACTORIES,
	Context.URL_PKG_PREFIXES,
	Context.STATE_FACTORIES,
	// The following shouldn't create a runtime dependence on ldap package.
	javax.naming.ldap.LdapContext.CONTROL_FACTORIES
	};

	private static final VersionHelper helper =
	VersionHelper.getVersionHelper();

	/*
	* A cache of the properties that have been constructed by
	* the ResourceManager. A Hashtable from a provider resource
	* file is keyed on a class in the resource file's package.
	* One from application resource files is keyed on the thread's
	* context class loader.
	*/
	// WeakHashMap<Class \| ClassLoader, Hashtable>
	private static final WeakHashMap<Object, Hashtable<? super String, Object>>
	propertiesCache = new WeakHashMap<>(11);

	/*
	* A cache of factory objects (ObjectFactory, StateFactory, ControlFactory).
	*
	* A two-level cache keyed first on context class loader and then
	* on propValue. Value is a list of class or factory objects,
	* weakly referenced so as not to prevent GC of the class loader.
	* Used in getFactories().
	*/
	private static final
	WeakHashMap<ClassLoader, Map<String, List<NamedWeakReference<Object>>>>
	factoryCache = new WeakHashMap<>(11);

	/*
	* A cache of URL factory objects (ObjectFactory).
	*
	* A two-level cache keyed first on context class loader and then
	* on classSuffix+propValue. Value is the factory itself (weakly
	* referenced so as not to prevent GC of the class loader) or
	* NO_FACTORY if a previous search revealed no factory. Used in
	* getFactory().
	*/
	private static final
	WeakHashMap<ClassLoader, Map<String, WeakReference<Object>>>
	urlFactoryCache = new WeakHashMap<>(11);
	private static final WeakReference<Object> NO_FACTORY =
	new WeakReference<>(null);

	/**
	* A class to allow JNDI properties be specified as applet parameters
	* without creating a static dependency on java.applet.
	*/
	private static class AppletParameter {
	private static final Class<?> clazz = getClass("java.applet.Applet");
	private static final Method getMethod =
	getMethod(clazz, "getParameter", String.class);
	private static Class<?> getClass(String name) {
	try {
	return Class.forName(name, true, null);
	} catch (ClassNotFoundException e) {
	return null;
	}
	}
	private static Method getMethod(Class<?> clazz,
	String name,
	Class<?>... paramTypes)
	{
	if (clazz != null) {
	try {
	return clazz.getMethod(name, paramTypes);
	} catch (NoSuchMethodException e) {
	throw new AssertionError(e);
	}
	} else {
	return null;
	}
	}

	/**
	* Returns the value of the applet's named parameter.
	*/
	static Object get(Object applet, String name) {
	// if clazz is null then applet cannot be an Applet.
	if (clazz == null \|\| !clazz.isInstance(applet))
	throw new ClassCastException(applet.getClass().getName());
	try {
	return getMethod.invoke(applet, name);
	} catch (InvocationTargetException \|
	IllegalAccessException e) {
	throw new AssertionError(e);
	}
	}
	}

	// There should be no instances of this class.
	private ResourceManager() {
	}


	// ---------- Public methods ----------

	/*
	* Given the environment parameter passed to the initial context
	* constructor, returns the full environment for that initial
	* context (never null). This is based on the environment
	* parameter, the applet parameters (where appropriate), the
	* system properties, and all application resource files.
	*
	* <p> This method will modify <tt>env</tt> and save
	* a reference to it. The caller may no longer modify it.
	*
	* @param env environment passed to initial context constructor.
	* Null indicates an empty environment.
	*
	* @throws NamingException if an error occurs while reading a
	* resource file
	*/
	@SuppressWarnings("unchecked")
	public static Hashtable<?, ?> getInitialEnvironment(
	Hashtable<?, ?> env)
	throws NamingException
	{
	String[] props = VersionHelper.PROPS; // system/applet properties
	if (env == null) {
	env = new Hashtable<>(11);
	}
	Object applet = env.get(Context.APPLET);

	// Merge property values from env param, applet params, and system
	// properties. The first value wins: there's no concatenation of
	// colon-separated lists.
	// Read system properties by first trying System.getProperties(),
	// and then trying System.getProperty() if that fails. The former
	// is more efficient due to fewer permission checks.
	//
	String[] jndiSysProps = helper.getJndiProperties();
	for (int i = 0; i < props.length; i++) {
	Object val = env.get(props[i]);
	if (val == null) {
	if (applet != null) {
	val = AppletParameter.get(applet, props[i]);
	}
	if (val == null) {
	// Read system property.
	val = (jndiSysProps != null)
	? jndiSysProps[i]
	: helper.getJndiProperty(i);
	}
	if (val != null) {
	((Hashtable<String, Object>)env).put(props[i], val);
	}
	}
	}

	// Return without merging if application resource files lookup
	// is disabled.
	String disableAppRes = (String)env.get(DISABLE_APP_RESOURCE_FILES);
	if (disableAppRes != null && disableAppRes.equalsIgnoreCase("true")) {
	return env;
	}

	// Merge the above with the values read from all application
	// resource files. Colon-separated lists are concatenated.
	mergeTables((Hashtable<Object, Object>)env, getApplicationResources());
	return env;
	}

	/**
	* Retrieves the property from the environment, or from the provider
	* resource file associated with the given context. The environment
	* may in turn contain values that come from applet parameters,
	* system properties, or application resource files.
	*
	* If <tt>concat</tt> is true and both the environment and the provider
	* resource file contain the property, the two values are concatenated
	* (with a ':' separator).
	*
	* Returns null if no value is found.
	*
	* @param propName The non-null property name
	* @param env The possibly null environment properties
	* @param ctx The possibly null context
	* @param concat True if multiple values should be concatenated
	* @return the property value, or null is there is none.
	* @throws NamingException if an error occurs while reading the provider
	* resource file.
	*/
	public static String getProperty(String propName, Hashtable<?,?> env,
	Context ctx, boolean concat)
	throws NamingException {

	String val1 = (env != null) ? (String)env.get(propName) : null;
	if ((ctx == null) \|\|
	((val1 != null) && !concat)) {
	return val1;
	}
	String val2 = (String)getProviderResource(ctx).get(propName);
	if (val1 == null) {
	return val2;
	} else if ((val2 == null) \|\| !concat) {
	return val1;
	} else {
	return (val1 + ":" + val2);
	}
	}

	/**
	* Retrieves an enumeration of factory classes/object specified by a
	* property.
	*
	* The property is gotten from the environment and the provider
	* resource file associated with the given context and concantenated.
	* See getProperty(). The resulting property value is a list of class names.
	*<p>
	* This method then loads each class using the current thread's context
	* class loader and keeps them in a list. Any class that cannot be loaded
	* is ignored. The resulting list is then cached in a two-level
	* hash table, keyed first by the context class loader and then by
	* the property's value.
	* The next time threads of the same context class loader call this
	* method, they can use the cached list.
	*<p>
	* After obtaining the list either from the cache or by creating one from
	* the property value, this method then creates and returns a
	* FactoryEnumeration using the list. As the FactoryEnumeration is
	* traversed, the cached Class object in the list is instantiated and
	* replaced by an instance of the factory object itself. Both class
	* objects and factories are wrapped in weak references so as not to
	* prevent GC of the class loader.
	*<p>
	* Note that multiple threads can be accessing the same cached list
	* via FactoryEnumeration, which locks the list during each next().
	* The size of the list will not change,
	* but a cached Class object might be replaced by an instantiated factory
	* object.
	*
	* @param propName The non-null property name
	* @param env The possibly null environment properties
	* @param ctx The possibly null context
	* @return An enumeration of factory classes/objects; null if none.
	* @exception NamingException If encounter problem while reading the provider
	* property file.
	* @see javax.naming.spi.NamingManager#getObjectInstance
	* @see javax.naming.spi.NamingManager#getStateToBind
	* @see javax.naming.spi.DirectoryManager#getObjectInstance
	* @see javax.naming.spi.DirectoryManager#getStateToBind
	* @see javax.naming.ldap.ControlFactory#getControlInstance
	*/
	public static FactoryEnumeration getFactories(String propName,
	Hashtable<?,?> env, Context ctx) throws NamingException {

	String facProp = getProperty(propName, env, ctx, true);
	if (facProp == null)
	return null; // no classes specified; return null

	// Cache is based on context class loader and property val
	ClassLoader loader = helper.getContextClassLoader();

	Map<String, List<NamedWeakReference<Object>>> perLoaderCache = null;
	synchronized (factoryCache) {
	perLoaderCache = factoryCache.get(loader);
	if (perLoaderCache == null) {
	perLoaderCache = new HashMap<>(11);
	factoryCache.put(loader, perLoaderCache);
	}
	}

	synchronized (perLoaderCache) {
	List<NamedWeakReference<Object>> factories =
	perLoaderCache.get(facProp);
	if (factories != null) {
	// Cached list
	return factories.size() == 0 ? null
	: new FactoryEnumeration(factories, loader);
	} else {
	// Populate list with classes named in facProp; skipping
	// those that we cannot load
	StringTokenizer parser = new StringTokenizer(facProp, ":");
	factories = new ArrayList<>(5);
	while (parser.hasMoreTokens()) {
	try {
	// System.out.println("loading");
	String className = parser.nextToken();
	Class<?> c = helper.loadClass(className, loader);
	factories.add(new NamedWeakReference<Object>(c, className));
	} catch (Exception e) {
	// ignore ClassNotFoundException, IllegalArgumentException
	}
	}
	// System.out.println("adding to cache: " + factories);
	perLoaderCache.put(facProp, factories);
	return new FactoryEnumeration(factories, loader);
	}
	}
	}

	/**
	* Retrieves a factory from a list of packages specified in a
	* property.
	*
	* The property is gotten from the environment and the provider
	* resource file associated with the given context and concatenated.
	* classSuffix is added to the end of this list.
	* See getProperty(). The resulting property value is a list of package
	* prefixes.
	*<p>
	* This method then constructs a list of class names by concatenating
	* each package prefix with classSuffix and attempts to load and
	* instantiate the class until one succeeds.
	* Any class that cannot be loaded is ignored.
	* The resulting object is then cached in a two-level hash table,
	* keyed first by the context class loader and then by the property's
	* value and classSuffix.
	* The next time threads of the same context class loader call this
	* method, they use the cached factory.
	* If no factory can be loaded, NO_FACTORY is recorded in the table
	* so that next time it'll return quickly.
	*
	* @param propName The non-null property name
	* @param env The possibly null environment properties
	* @param ctx The possibly null context
	* @param classSuffix The non-null class name
	* (e.g. ".ldap.ldapURLContextFactory).
	* @param defaultPkgPrefix The non-null default package prefix.
	* (e.g., "com.sun.jndi.url").
	* @return An factory object; null if none.
	* @exception NamingException If encounter problem while reading the provider
	* property file, or problem instantiating the factory.
	*
	* @see javax.naming.spi.NamingManager#getURLContext
	* @see javax.naming.spi.NamingManager#getURLObject
	*/
	public static Object getFactory(String propName, Hashtable<?,?> env,
	Context ctx, String classSuffix, String defaultPkgPrefix)
	throws NamingException {

	// Merge property with provider property and supplied default
	String facProp = getProperty(propName, env, ctx, true);
	if (facProp != null)
	facProp += (":" + defaultPkgPrefix);
	else
	facProp = defaultPkgPrefix;

	// Cache factory based on context class loader, class name, and
	// property val
	ClassLoader loader = helper.getContextClassLoader();
	String key = classSuffix + " " + facProp;

	Map<String, WeakReference<Object>> perLoaderCache = null;
	synchronized (urlFactoryCache) {
	perLoaderCache = urlFactoryCache.get(loader);
	if (perLoaderCache == null) {
	perLoaderCache = new HashMap<>(11);
	urlFactoryCache.put(loader, perLoaderCache);
	}
	}

	synchronized (perLoaderCache) {
	Object factory = null;

	WeakReference<Object> factoryRef = perLoaderCache.get(key);
	if (factoryRef == NO_FACTORY) {
	return null;
	} else if (factoryRef != null) {
	factory = factoryRef.get();
	if (factory != null) { // check if weak ref has been cleared
	return factory;
	}
	}

	// Not cached; find first factory and cache
	StringTokenizer parser = new StringTokenizer(facProp, ":");
	String className;
	while (factory == null && parser.hasMoreTokens()) {
	className = parser.nextToken() + classSuffix;
	try {
	// System.out.println("loading " + className);
	factory = helper.loadClass(className, loader).newInstance();
	} catch (InstantiationException e) {
	NamingException ne =
	new NamingException("Cannot instantiate " + className);
	ne.setRootCause(e);
	throw ne;
	} catch (IllegalAccessException e) {
	NamingException ne =
	new NamingException("Cannot access " + className);
	ne.setRootCause(e);
	throw ne;
	} catch (Exception e) {
	// ignore ClassNotFoundException, IllegalArgumentException,
	// etc.
	}
	}

	// Cache it.
	perLoaderCache.put(key, (factory != null)
	? new WeakReference<>(factory)
	: NO_FACTORY);
	return factory;
	}
	}


	// ---------- Private methods ----------

	/*
	* Returns the properties contained in the provider resource file
	* of an object's package. Returns an empty hash table if the
	* object is null or the resource file cannot be found. The
	* results are cached.
	*
	* @throws NamingException if an error occurs while reading the file.
	*/
	private static Hashtable<? super String, Object>
	getProviderResource(Object obj)
	throws NamingException
	{
	if (obj == null) {
	return (new Hashtable<>(1));
	}
	synchronized (propertiesCache) {
	Class<?> c = obj.getClass();

	Hashtable<? super String, Object> props =
	propertiesCache.get(c);
	if (props != null) {
	return props;
	}
	props = new Properties();

	InputStream istream =
	helper.getResourceAsStream(c, PROVIDER_RESOURCE_FILE_NAME);

	if (istream != null) {
	try {
	((Properties)props).load(istream);
	} catch (IOException e) {
	NamingException ne = new ConfigurationException(
	"Error reading provider resource file for " + c);
	ne.setRootCause(e);
	throw ne;
	}
	}
	propertiesCache.put(c, props);
	return props;
	}
	}


	/*
	* Returns the Hashtable (never null) that results from merging
	* all application resource files available to this thread's
	* context class loader. The properties file in <java.home>/lib
	* is also merged in. The results are cached.
	*
	* SECURITY NOTES:
	* 1. JNDI needs permission to read the application resource files.
	* 2. Any class will be able to use JNDI to view the contents of
	* the application resource files in its own classpath. Give
	* careful consideration to this before storing sensitive
	* information there.
	*
	* @throws NamingException if an error occurs while reading a resource
	* file.
	*/
	private static Hashtable<? super String, Object> getApplicationResources()
	throws NamingException {

	ClassLoader cl = helper.getContextClassLoader();

	synchronized (propertiesCache) {
	Hashtable<? super String, Object> result = propertiesCache.get(cl);
	if (result != null) {
	return result;
	}

	try {
	NamingEnumeration<InputStream> resources =
	helper.getResources(cl, APP_RESOURCE_FILE_NAME);
	try {
	while (resources.hasMore()) {
	Properties props = new Properties();
	InputStream istream = resources.next();
	try {
	props.load(istream);
	} finally {
	istream.close();
	}

	if (result == null) {
	result = props;
	} else {
	mergeTables(result, props);
	}
	}
	} finally {
	while (resources.hasMore()) {
	resources.next().close();
	}
	}

	// Merge in properties from file in <java.home>/lib.
	InputStream istream =
	helper.getJavaHomeLibStream(JRELIB_PROPERTY_FILE_NAME);
	if (istream != null) {
	try {
	Properties props = new Properties();
	props.load(istream);

	if (result == null) {
	result = props;
	} else {
	mergeTables(result, props);
	}
	} finally {
	istream.close();
	}
	}

	} catch (IOException e) {
	NamingException ne = new ConfigurationException(
	"Error reading application resource file");
	ne.setRootCause(e);
	throw ne;
	}
	if (result == null) {
	result = new Hashtable<>(11);
	}
	propertiesCache.put(cl, result);
	return result;
	}
	}

	/*
	* Merge the properties from one hash table into another. Each
	* property in props2 that is not in props1 is added to props1.
	* For each property in both hash tables that is one of the
	* standard JNDI properties that specify colon-separated lists,
	* the values are concatenated and stored in props1.
	*/
	private static void mergeTables(Hashtable<? super String, Object> props1,
	Hashtable<? super String, Object> props2) {
	for (Object key : props2.keySet()) {
	String prop = (String)key;
	Object val1 = props1.get(prop);
	if (val1 == null) {
	props1.put(prop, props2.get(prop));
	} else if (isListProperty(prop)) {
	String val2 = (String)props2.get(prop);
	props1.put(prop, ((String)val1) + ":" + val2);
	}
	}
	}

	/*
	* Is a property one of the standard JNDI properties that specify
	* colon-separated lists?
	*/
	private static boolean isListProperty(String prop) {
	prop = prop.intern();
	for (int i = 0; i < listProperties.length; i++) {
	if (prop == listProperties[i]) {
	return true;
	}
	}
	return false;
	}
	}

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