src/java.naming/share/classes/com/sun/naming/internal/VersionHelper.java
changeset 47216 71c04702a3d5
parent 44545 83b611b88ac8
child 52165 6c014b7762a2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.naming/share/classes/com/sun/naming/internal/VersionHelper.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,340 @@
+/*
+ * Copyright (c) 1999, 2014, 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 javax.naming.NamingEnumeration;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+import java.security.PrivilegedActionException;
+import java.security.PrivilegedExceptionAction;
+import java.util.*;
+
+/**
+ * VersionHelper was used by JNDI to accommodate differences between
+ * JDK 1.1.x and the Java 2 platform. As this is no longer necessary
+ * since JNDI's inclusion in the platform, this class currently
+ * serves as a set of utilities for performing system-level things,
+ * such as class-loading and reading system properties.
+ *
+ * @author Rosanna Lee
+ * @author Scott Seligman
+ */
+
+public final class VersionHelper {
+    private static final VersionHelper helper = new VersionHelper();
+
+    final static String[] PROPS = new String[]{
+        javax.naming.Context.INITIAL_CONTEXT_FACTORY,
+        javax.naming.Context.OBJECT_FACTORIES,
+        javax.naming.Context.URL_PKG_PREFIXES,
+        javax.naming.Context.STATE_FACTORIES,
+        javax.naming.Context.PROVIDER_URL,
+        javax.naming.Context.DNS_URL,
+        // The following shouldn't create a runtime dependence on ldap package.
+        javax.naming.ldap.LdapContext.CONTROL_FACTORIES
+    };
+
+    public final static int INITIAL_CONTEXT_FACTORY = 0;
+    public final static int OBJECT_FACTORIES = 1;
+    public final static int URL_PKG_PREFIXES = 2;
+    public final static int STATE_FACTORIES = 3;
+    public final static int PROVIDER_URL = 4;
+    public final static int DNS_URL = 5;
+    public final static int CONTROL_FACTORIES = 6;
+
+    private VersionHelper() {} // Disallow anyone from creating one of these.
+
+    public static VersionHelper getVersionHelper() {
+        return helper;
+    }
+
+    public Class<?> loadClass(String className) throws ClassNotFoundException {
+        return loadClass(className, getContextClassLoader());
+    }
+
+    /**
+     * @param className A non-null fully qualified class name.
+     * @param codebase  A non-null, space-separated list of URL strings.
+     */
+    public Class<?> loadClass(String className, String codebase)
+            throws ClassNotFoundException, MalformedURLException {
+
+        ClassLoader parent = getContextClassLoader();
+        ClassLoader cl =
+                URLClassLoader.newInstance(getUrlArray(codebase), parent);
+
+        return loadClass(className, cl);
+    }
+
+    /**
+     * Package private.
+     * <p>
+     * This internal method is used with Thread Context Class Loader (TCCL),
+     * please don't expose this method as public.
+     */
+    Class<?> loadClass(String className, ClassLoader cl)
+            throws ClassNotFoundException {
+        Class<?> cls = Class.forName(className, true, cl);
+        return cls;
+    }
+
+    /*
+     * Returns a JNDI property from the system properties. Returns
+     * null if the property is not set, or if there is no permission
+     * to read it.
+     */
+    String getJndiProperty(int i) {
+        PrivilegedAction<String> act = () -> {
+            try {
+                return System.getProperty(PROPS[i]);
+            } catch (SecurityException e) {
+                return null;
+            }
+        };
+        return AccessController.doPrivileged(act);
+    }
+
+    /*
+     * Reads each property in PROPS from the system properties, and
+     * returns their values -- in order -- in an array.  For each
+     * unset property, the corresponding array element is set to null.
+     * Returns null if there is no permission to call System.getProperties().
+     */
+    String[] getJndiProperties() {
+        PrivilegedAction<Properties> act = () -> {
+            try {
+                return System.getProperties();
+            } catch (SecurityException e) {
+                return null;
+            }
+        };
+        Properties sysProps = AccessController.doPrivileged(act);
+        if (sysProps == null) {
+            return null;
+        }
+        String[] jProps = new String[PROPS.length];
+        for (int i = 0; i < PROPS.length; i++) {
+            jProps[i] = sysProps.getProperty(PROPS[i]);
+        }
+        return jProps;
+    }
+
+    private static String resolveName(Class<?> c, String name) {
+        if (name == null) {
+            return name;
+        }
+        if (!name.startsWith("/")) {
+            while (c.isArray()) {
+                c = c.getComponentType();
+            }
+            String baseName = c.getName();
+            int index = baseName.lastIndexOf('.');
+            if (index != -1) {
+                name = baseName.substring(0, index).replace('.', '/')
+                    +"/"+name;
+            }
+        } else {
+            name = name.substring(1);
+        }
+        return name;
+    }
+
+    /*
+     * Returns the resource of a given name associated with a particular
+     * class (never null), or null if none can be found.
+     */
+    InputStream getResourceAsStream(Class<?> c, String name) {
+        PrivilegedAction<InputStream> act = () -> {
+            try {
+                Module m = c.getModule();
+                return c.getModule().getResourceAsStream(resolveName(c,name));
+             } catch (IOException x) {
+                 return null;
+             }
+        };
+        return AccessController.doPrivileged(act);
+    }
+
+    /*
+     * Returns an input stream for a file in <java.home>/conf,
+     * or null if it cannot be located or opened.
+     *
+     * @param filename  The file name, sans directory.
+     */
+    InputStream getJavaHomeConfStream(String filename) {
+        PrivilegedAction<InputStream> act = () -> {
+            try {
+                String javahome = System.getProperty("java.home");
+                if (javahome == null) {
+                    return null;
+                }
+                String pathname = javahome + File.separator +
+                        "conf" + File.separator + filename;
+                return new FileInputStream(pathname);
+            } catch (Exception e) {
+                return null;
+            }
+        };
+        return AccessController.doPrivileged(act);
+    }
+
+    /*
+     * Returns an enumeration (never null) of InputStreams of the
+     * resources of a given name associated with a particular class
+     * loader.  Null represents the bootstrap class loader in some
+     * Java implementations.
+     */
+    NamingEnumeration<InputStream> getResources(ClassLoader cl,
+                                                String name) throws IOException {
+        Enumeration<URL> urls;
+        PrivilegedExceptionAction<Enumeration<URL>> act = () ->
+                (cl == null)
+                        ? ClassLoader.getSystemResources(name)
+                        : cl.getResources(name);
+        try {
+            urls = AccessController.doPrivileged(act);
+        } catch (PrivilegedActionException e) {
+            throw (IOException) e.getException();
+        }
+        return new InputStreamEnumeration(urls);
+    }
+
+
+    /**
+     * Package private.
+     * <p>
+     * This internal method returns Thread Context Class Loader (TCCL),
+     * if null, returns the system Class Loader.
+     * <p>
+     * Please don't expose this method as public.
+     * @throws SecurityException if the class loader is not accessible
+     */
+    ClassLoader getContextClassLoader() {
+
+        PrivilegedAction<ClassLoader> act = () -> {
+            ClassLoader loader = Thread.currentThread().getContextClassLoader();
+            if (loader == null) {
+                // Don't use bootstrap class loader directly!
+                loader = ClassLoader.getSystemClassLoader();
+            }
+            return loader;
+        };
+        return AccessController.doPrivileged(act);
+    }
+
+    private static URL[] getUrlArray(String codebase)
+            throws MalformedURLException {
+        // Parse codebase into separate URLs
+        StringTokenizer parser = new StringTokenizer(codebase);
+        List<String> list = new ArrayList<>();
+        while (parser.hasMoreTokens()) {
+            list.add(parser.nextToken());
+        }
+        String[] url = new String[list.size()];
+        for (int i = 0; i < url.length; i++) {
+            url[i] = list.get(i);
+        }
+
+        URL[] urlArray = new URL[url.length];
+        for (int i = 0; i < urlArray.length; i++) {
+            urlArray[i] = new URL(url[i]);
+        }
+        return urlArray;
+    }
+
+    /**
+     * Given an enumeration of URLs, an instance of this class represents
+     * an enumeration of their InputStreams.  Each operation on the URL
+     * enumeration is performed within a doPrivileged block.
+     * This is used to enumerate the resources under a foreign codebase.
+     * This class is not MT-safe.
+     */
+    private class InputStreamEnumeration implements
+            NamingEnumeration<InputStream> {
+
+        private final Enumeration<URL> urls;
+
+        private InputStream nextElement;
+
+        InputStreamEnumeration(Enumeration<URL> urls) {
+            this.urls = urls;
+        }
+
+        /*
+         * Returns the next InputStream, or null if there are no more.
+         * An InputStream that cannot be opened is skipped.
+         */
+        private InputStream getNextElement() {
+            PrivilegedAction<InputStream> act = () -> {
+                while (urls.hasMoreElements()) {
+                    try {
+                        return urls.nextElement().openStream();
+                    } catch (IOException e) {
+                        // skip this URL
+                    }
+                }
+                return null;
+            };
+            return AccessController.doPrivileged(act);
+        }
+
+        public boolean hasMore() {
+            if (nextElement != null) {
+                return true;
+            }
+            nextElement = getNextElement();
+            return (nextElement != null);
+        }
+
+        public boolean hasMoreElements() {
+            return hasMore();
+        }
+
+        public InputStream next() {
+            if (hasMore()) {
+                InputStream res = nextElement;
+                nextElement = null;
+                return res;
+            } else {
+                throw new NoSuchElementException();
+            }
+        }
+
+        public InputStream nextElement() {
+            return next();
+        }
+
+        public void close() {
+        }
+    }
+}