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	/*
	* Copyright (c) 2015, 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.util.spi;

	import jdk.internal.access.JavaUtilResourceBundleAccess;
	import jdk.internal.access.SharedSecrets;
	import sun.util.resources.Bundles;

	import java.io.IOException;
	import java.io.InputStream;
	import java.io.UncheckedIOException;
	import java.security.AccessController;
	import java.security.PrivilegedAction;
	import java.util.Locale;
	import java.util.PropertyResourceBundle;
	import java.util.ResourceBundle;
	import static sun.security.util.SecurityConstants.GET_CLASSLOADER_PERMISSION;

	/**
	* {@code AbstractResourceBundleProvider} is an abstract class that provides
	* the basic support for a provider implementation class for
	* {@link ResourceBundleProvider}.
	*
	* <p>
	* Resource bundles can be packaged in one or more
	* named modules, <em>service provider modules</em>. The <em>consumer</em> of the
	* resource bundle is the one calling {@link ResourceBundle#getBundle(String)}.
	* In order for the consumer module to load a resource bundle
	* "{@code com.example.app.MyResources}" provided by another module,
	* it will use the {@linkplain java.util.ServiceLoader service loader}
	* mechanism. A service interface named "{@code com.example.app.spi.MyResourcesProvider}"
	* must be defined and a <em>service provider module</em> will provide an
	* implementation class of "{@code com.example.app.spi.MyResourcesProvider}"
	* as follows:
	*
	* <blockquote><pre>
	* {@code import com.example.app.spi.MyResourcesProvider;
	* class MyResourcesProviderImpl extends AbstractResourceBundleProvider
	* implements MyResourcesProvider
	* {
	* public MyResourcesProviderImpl() {
	* super("java.properties");
	* }
	* // this provider maps the resource bundle to per-language package
	* protected String toBundleName(String baseName, Locale locale) {
	* return "p." + locale.getLanguage() + "." + baseName;
	* }
	*
	* public ResourceBundle getBundle(String baseName, Locale locale) {
	* // this module only provides bundles in French
	* if (locale.equals(Locale.FRENCH)) {
	* return super.getBundle(baseName, locale);
	* }
	* // otherwise return null
	* return null;
	* }
	* }}</pre></blockquote>
	*
	* Refer to {@link ResourceBundleProvider} for details.
	*
	* @see <a href="../ResourceBundle.html#resource-bundle-modules">
	* Resource Bundles and Named Modules</a>
	* @since 9
	*/
	public abstract class AbstractResourceBundleProvider implements ResourceBundleProvider {
	private static final JavaUtilResourceBundleAccess RB_ACCESS =
	SharedSecrets.getJavaUtilResourceBundleAccess();

	private static final String FORMAT_CLASS = "java.class";
	private static final String FORMAT_PROPERTIES = "java.properties";

	private final String[] formats;

	/**
	* Constructs an {@code AbstractResourceBundleProvider} with the
	* "java.properties" format. This constructor is equivalent to
	* {@code AbstractResourceBundleProvider("java.properties")}.
	*/
	protected AbstractResourceBundleProvider() {
	this(FORMAT_PROPERTIES);
	}

	/**
	* Constructs an {@code AbstractResourceBundleProvider} with the specified
	* {@code formats}. The {@link #getBundle(String, Locale)} method looks up
	* resource bundles for the given {@code formats}. {@code formats} must
	* be "java.class" or "java.properties".
	*
	* @param formats the formats to be used for loading resource bundles
	* @throws NullPointerException if the given {@code formats} is null
	* @throws IllegalArgumentException if the given {@code formats} is not
	* "java.class" or "java.properties".
	*/
	protected AbstractResourceBundleProvider(String... formats) {
	this.formats = formats.clone(); // defensive copy
	if (this.formats.length == 0) {
	throw new IllegalArgumentException("empty formats");
	}
	for (String f : this.formats) {
	if (!FORMAT_CLASS.equals(f) && !FORMAT_PROPERTIES.equals(f)) {
	throw new IllegalArgumentException(f);
	}
	}
	}

	/**
	* Returns the bundle name for the given {@code baseName} and {@code
	* locale} that this provider provides.
	*
	* @apiNote
	* A resource bundle provider may package its resource bundles in the
	* same package as the base name of the resource bundle if the package
	* is not split among other named modules. If there are more than one
	* bundle providers providing the resource bundle of a given base name,
	* the resource bundles can be packaged with per-language grouping
	* or per-region grouping to eliminate the split packages.
	*
	* <p>For example, if {@code baseName} is {@code "p.resources.Bundle"} then
	* the resource bundle name of {@code "p.resources.Bundle"} of
	* <code style="white-space:nowrap">Locale("ja", "", "XX")</code>
	* and {@code Locale("en")} could be <code style="white-space:nowrap">
	* "p.resources.ja.Bundle_ja_ _XX"</code> and
	* {@code "p.resources.Bundle_en"} respectively.
	*
	* <p> This method is called from the default implementation of the
	* {@link #getBundle(String, Locale)} method.
	*
	* @implNote The default implementation of this method is the same as the
	* implementation of
	* {@link java.util.ResourceBundle.Control#toBundleName(String, Locale)}.
	*
	* @param baseName the base name of the resource bundle, a fully qualified
	* class name
	* @param locale the locale for which a resource bundle should be loaded
	* @return the bundle name for the resource bundle
	*/
	protected String toBundleName(String baseName, Locale locale) {
	return ResourceBundle.Control.getControl(ResourceBundle.Control.FORMAT_DEFAULT)
	.toBundleName(baseName, locale);
	}

	/**
	* Returns a {@code ResourceBundle} for the given {@code baseName} and
	* {@code locale}.
	*
	* @implNote
	* The default implementation of this method calls the
	* {@link #toBundleName(String, Locale) toBundleName} method to get the
	* bundle name for the {@code baseName} and {@code locale} and finds the
	* resource bundle of the bundle name local in the module of this provider.
	* It will only search the formats specified when this provider was
	* constructed.
	*
	* @param baseName the base bundle name of the resource bundle, a fully
	* qualified class name.
	* @param locale the locale for which the resource bundle should be instantiated
	* @return {@code ResourceBundle} of the given {@code baseName} and
	* {@code locale}, or {@code null} if no resource bundle is found
	* @throws NullPointerException if {@code baseName} or {@code locale} is
	* {@code null}
	* @throws UncheckedIOException if any IO exception occurred during resource
	* bundle loading
	*/
	@Override
	public ResourceBundle getBundle(String baseName, Locale locale) {
	Module module = this.getClass().getModule();
	String bundleName = toBundleName(baseName, locale);
	var bundle = getBundle0(module, bundleName);
	if (bundle == null) {
	var otherBundleName = Bundles.toOtherBundleName(baseName, bundleName, locale);
	if (!bundleName.equals(otherBundleName)) {
	bundle = getBundle0(module, Bundles.toOtherBundleName(baseName, bundleName, locale));
	}
	}
	return bundle;
	}

	private ResourceBundle getBundle0(Module module, String bundleName) {
	ResourceBundle bundle = null;

	for (String format : formats) {
	try {
	if (FORMAT_CLASS.equals(format)) {
	bundle = loadResourceBundle(module, bundleName);
	} else if (FORMAT_PROPERTIES.equals(format)) {
	bundle = loadPropertyResourceBundle(module, bundleName);
	}
	if (bundle != null) {
	break;
	}
	} catch (IOException e) {
	throw new UncheckedIOException(e);
	}
	}
	return bundle;
	}

	/*
	* Returns the ResourceBundle of .class format if found in the module
	* of this provider.
	*/
	private static ResourceBundle loadResourceBundle(Module module, String bundleName)
	{
	PrivilegedAction<Class<?>> pa = () -> Class.forName(module, bundleName);
	@SuppressWarnings("removal")
	Class<?> c = AccessController.doPrivileged(pa, null, GET_CLASSLOADER_PERMISSION);
	if (c != null && ResourceBundle.class.isAssignableFrom(c)) {
	@SuppressWarnings("unchecked")
	Class<ResourceBundle> bundleClass = (Class<ResourceBundle>) c;
	return RB_ACCESS.newResourceBundle(bundleClass);
	}
	return null;
	}

	/*
	* Returns the ResourceBundle of .property format if found in the module
	* of this provider.
	*/
	private static ResourceBundle loadPropertyResourceBundle(Module module,
	String bundleName)
	throws IOException
	{
	String resourceName = toResourceName(bundleName, "properties");
	if (resourceName == null) {
	return null;
	}

	PrivilegedAction<InputStream> pa = () -> {
	try {
	return module.getResourceAsStream(resourceName);
	} catch (IOException e) {
	throw new UncheckedIOException(e);
	}
	};
	try (@SuppressWarnings("removal") InputStream stream = AccessController.doPrivileged(pa)) {
	if (stream != null) {
	return new PropertyResourceBundle(stream);
	} else {
	return null;
	}
	} catch (UncheckedIOException e) {
	throw e.getCause();
	}
	}

	private static String toResourceName(String bundleName, String suffix) {
	if (bundleName.contains("://")) {
	return null;
	}
	StringBuilder sb = new StringBuilder(bundleName.length() + 1 + suffix.length());
	sb.append(bundleName.replace('.', '/')).append('.').append(suffix);
	return sb.toString();
	}

	}

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