rev 14210 : 8154231: Simplify access to System properties from JDK code
Reviewed-by: rriggs

   1 /*
   2  * Copyright (c) 1995, 2015, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package java.net;
  27 
  28 import java.io.IOException;
  29 import java.io.InputStream;
  30 import java.net.spi.URLStreamHandlerProvider;
  31 import java.security.AccessController;
  32 import java.security.PrivilegedAction;
  33 import java.util.Hashtable;
  34 import java.io.InvalidObjectException;
  35 import java.io.ObjectStreamException;
  36 import java.io.ObjectStreamField;
  37 import java.io.ObjectInputStream.GetField;
  38 import java.util.Iterator;
  39 import java.util.Locale;
  40 import java.util.NoSuchElementException;
  41 import java.util.ServiceConfigurationError;
  42 import java.util.ServiceLoader;
  43 
  44 import sun.security.util.SecurityConstants;

  45 
  46 /**
  47  * Class {@code URL} represents a Uniform Resource
  48  * Locator, a pointer to a "resource" on the World
  49  * Wide Web. A resource can be something as simple as a file or a
  50  * directory, or it can be a reference to a more complicated object,
  51  * such as a query to a database or to a search engine. More
  52  * information on the types of URLs and their formats can be found at:
  53  * <a href=
  54  * "http://web.archive.org/web/20051219043731/http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/Demo/url-primer.html">
  55  * <i>Types of URL</i></a>
  56  * <p>
  57  * In general, a URL can be broken into several parts. Consider the
  58  * following example:
  59  * <blockquote><pre>
  60  *     http://www.example.com/docs/resource1.html
  61  * </pre></blockquote>
  62  * <p>
  63  * The URL above indicates that the protocol to use is
  64  * {@code http} (HyperText Transfer Protocol) and that the
  65  * information resides on a host machine named
  66  * {@code www.example.com}. The information on that host
  67  * machine is named {@code /docs/resource1.html}. The exact
  68  * meaning of this name on the host machine is both protocol
  69  * dependent and host dependent. The information normally resides in
  70  * a file, but it could be generated on the fly. This component of
  71  * the URL is called the <i>path</i> component.
  72  * <p>
  73  * A URL can optionally specify a "port", which is the
  74  * port number to which the TCP connection is made on the remote host
  75  * machine. If the port is not specified, the default port for
  76  * the protocol is used instead. For example, the default port for
  77  * {@code http} is {@code 80}. An alternative port could be
  78  * specified as:
  79  * <blockquote><pre>
  80  *     http://www.example.com:1080/docs/resource1.html
  81  * </pre></blockquote>
  82  * <p>
  83  * The syntax of {@code URL} is defined by  <a
  84  * href="http://www.ietf.org/rfc/rfc2396.txt"><i>RFC&nbsp;2396: Uniform
  85  * Resource Identifiers (URI): Generic Syntax</i></a>, amended by <a
  86  * href="http://www.ietf.org/rfc/rfc2732.txt"><i>RFC&nbsp;2732: Format for
  87  * Literal IPv6 Addresses in URLs</i></a>. The Literal IPv6 address format
  88  * also supports scope_ids. The syntax and usage of scope_ids is described
  89  * <a href="Inet6Address.html#scoped">here</a>.
  90  * <p>
  91  * A URL may have appended to it a "fragment", also known
  92  * as a "ref" or a "reference". The fragment is indicated by the sharp
  93  * sign character "#" followed by more characters. For example,
  94  * <blockquote><pre>
  95  *     http://java.sun.com/index.html#chapter1
  96  * </pre></blockquote>
  97  * <p>
  98  * This fragment is not technically part of the URL. Rather, it
  99  * indicates that after the specified resource is retrieved, the
 100  * application is specifically interested in that part of the
 101  * document that has the tag {@code chapter1} attached to it. The
 102  * meaning of a tag is resource specific.
 103  * <p>
 104  * An application can also specify a "relative URL",
 105  * which contains only enough information to reach the resource
 106  * relative to another URL. Relative URLs are frequently used within
 107  * HTML pages. For example, if the contents of the URL:
 108  * <blockquote><pre>
 109  *     http://java.sun.com/index.html
 110  * </pre></blockquote>
 111  * contained within it the relative URL:
 112  * <blockquote><pre>
 113  *     FAQ.html
 114  * </pre></blockquote>
 115  * it would be a shorthand for:
 116  * <blockquote><pre>
 117  *     http://java.sun.com/FAQ.html
 118  * </pre></blockquote>
 119  * <p>
 120  * The relative URL need not specify all the components of a URL. If
 121  * the protocol, host name, or port number is missing, the value is
 122  * inherited from the fully specified URL. The file component must be
 123  * specified. The optional fragment is not inherited.
 124  * <p>
 125  * The URL class does not itself encode or decode any URL components
 126  * according to the escaping mechanism defined in RFC2396. It is the
 127  * responsibility of the caller to encode any fields, which need to be
 128  * escaped prior to calling URL, and also to decode any escaped fields,
 129  * that are returned from URL. Furthermore, because URL has no knowledge
 130  * of URL escaping, it does not recognise equivalence between the encoded
 131  * or decoded form of the same URL. For example, the two URLs:<br>
 132  * <pre>    http://foo.com/hello world/ and http://foo.com/hello%20world</pre>
 133  * would be considered not equal to each other.
 134  * <p>
 135  * Note, the {@link java.net.URI} class does perform escaping of its
 136  * component fields in certain circumstances. The recommended way
 137  * to manage the encoding and decoding of URLs is to use {@link java.net.URI},
 138  * and to convert between these two classes using {@link #toURI()} and
 139  * {@link URI#toURL()}.
 140  * <p>
 141  * The {@link URLEncoder} and {@link URLDecoder} classes can also be
 142  * used, but only for HTML form encoding, which is not the same
 143  * as the encoding scheme defined in RFC2396.
 144  *
 145  * @author  James Gosling
 146  * @since 1.0
 147  */
 148 public final class URL implements java.io.Serializable {
 149 
 150     static final String BUILTIN_HANDLERS_PREFIX = "sun.net.www.protocol";
 151     static final long serialVersionUID = -7627629688361524110L;
 152 
 153     /**
 154      * The property which specifies the package prefix list to be scanned
 155      * for protocol handlers.  The value of this property (if any) should
 156      * be a vertical bar delimited list of package names to search through
 157      * for a protocol handler to load.  The policy of this class is that
 158      * all protocol handlers will be in a class called <protocolname>.Handler,
 159      * and each package in the list is examined in turn for a matching
 160      * handler.  If none are found (or the property is not specified), the
 161      * default package prefix, sun.net.www.protocol, is used.  The search
 162      * proceeds from the first package in the list to the last and stops
 163      * when a match is found.
 164      */
 165     private static final String protocolPathProp = "java.protocol.handler.pkgs";
 166 
 167     /**
 168      * The protocol to use (ftp, http, nntp, ... etc.) .
 169      * @serial
 170      */
 171     private String protocol;
 172 
 173     /**
 174      * The host name to connect to.
 175      * @serial
 176      */
 177     private String host;
 178 
 179     /**
 180      * The protocol port to connect to.
 181      * @serial
 182      */
 183     private int port = -1;
 184 
 185     /**
 186      * The specified file name on that host. {@code file} is
 187      * defined as {@code path[?query]}
 188      * @serial
 189      */
 190     private String file;
 191 
 192     /**
 193      * The query part of this URL.
 194      */
 195     private transient String query;
 196 
 197     /**
 198      * The authority part of this URL.
 199      * @serial
 200      */
 201     private String authority;
 202 
 203     /**
 204      * The path part of this URL.
 205      */
 206     private transient String path;
 207 
 208     /**
 209      * The userinfo part of this URL.
 210      */
 211     private transient String userInfo;
 212 
 213     /**
 214      * # reference.
 215      * @serial
 216      */
 217     private String ref;
 218 
 219     /**
 220      * The host's IP address, used in equals and hashCode.
 221      * Computed on demand. An uninitialized or unknown hostAddress is null.
 222      */
 223     transient InetAddress hostAddress;
 224 
 225     /**
 226      * The URLStreamHandler for this URL.
 227      */
 228     transient URLStreamHandler handler;
 229 
 230     /* Our hash code.
 231      * @serial
 232      */
 233     private int hashCode = -1;
 234 
 235     private transient UrlDeserializedState tempState;
 236 
 237     /**
 238      * Creates a {@code URL} object from the specified
 239      * {@code protocol}, {@code host}, {@code port}
 240      * number, and {@code file}.<p>
 241      *
 242      * {@code host} can be expressed as a host name or a literal
 243      * IP address. If IPv6 literal address is used, it should be
 244      * enclosed in square brackets ({@code '['} and {@code ']'}), as
 245      * specified by <a
 246      * href="http://www.ietf.org/rfc/rfc2732.txt">RFC&nbsp;2732</a>;
 247      * However, the literal IPv6 address format defined in <a
 248      * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC&nbsp;2373: IP
 249      * Version 6 Addressing Architecture</i></a> is also accepted.<p>
 250      *
 251      * Specifying a {@code port} number of {@code -1}
 252      * indicates that the URL should use the default port for the
 253      * protocol.<p>
 254      *
 255      * If this is the first URL object being created with the specified
 256      * protocol, a <i>stream protocol handler</i> object, an instance of
 257      * class {@code URLStreamHandler}, is created for that protocol:
 258      * <ol>
 259      * <li>If the application has previously set up an instance of
 260      *     {@code URLStreamHandlerFactory} as the stream handler factory,
 261      *     then the {@code createURLStreamHandler} method of that instance
 262      *     is called with the protocol string as an argument to create the
 263      *     stream protocol handler.
 264      * <li>If no {@code URLStreamHandlerFactory} has yet been set up,
 265      *     or if the factory's {@code createURLStreamHandler} method
 266      *     returns {@code null}, then the {@linkplain java.util.ServiceLoader
 267      *     ServiceLoader} mechanism is used to locate {@linkplain
 268      *     java.net.spi.URLStreamHandlerProvider URLStreamHandlerProvider}
 269      *     implementations using the system class
 270      *     loader. The order that providers are located is implementation
 271      *     specific, and an implementation is free to cache the located
 272      *     providers. A {@linkplain java.util.ServiceConfigurationError
 273      *     ServiceConfigurationError}, {@code Error} or {@code RuntimeException}
 274      *     thrown from the {@code createURLStreamHandler}, if encountered, will
 275      *     be propagated to the calling thread. The {@code
 276      *     createURLStreamHandler} method of each provider, if instantiated, is
 277      *     invoked, with the protocol string, until a provider returns non-null,
 278      *     or all providers have been exhausted.
 279      * <li>If the previous step fails to find a protocol handler, the
 280      *     constructor reads the value of the system property:
 281      *     <blockquote>{@code
 282      *         java.protocol.handler.pkgs
 283      *     }</blockquote>
 284      *     If the value of that system property is not {@code null},
 285      *     it is interpreted as a list of packages separated by a vertical
 286      *     slash character '{@code |}'. The constructor tries to load
 287      *     the class named:
 288      *     <blockquote>{@code
 289      *         <package>.<protocol>.Handler
 290      *     }</blockquote>
 291      *     where {@code <package>} is replaced by the name of the package
 292      *     and {@code <protocol>} is replaced by the name of the protocol.
 293      *     If this class does not exist, or if the class exists but it is not
 294      *     a subclass of {@code URLStreamHandler}, then the next package
 295      *     in the list is tried.
 296      * <li>If the previous step fails to find a protocol handler, then the
 297      *     constructor tries to load a built-in protocol handler.
 298      *     If this class does not exist, or if the class exists but it is not a
 299      *     subclass of {@code URLStreamHandler}, then a
 300      *     {@code MalformedURLException} is thrown.
 301      * </ol>
 302      *
 303      * <p>Protocol handlers for the following protocols are guaranteed
 304      * to exist on the search path :-
 305      * <blockquote><pre>
 306      *     http, https, file, and jar
 307      * </pre></blockquote>
 308      * Protocol handlers for additional protocols may also be  available.
 309      * Some protocol handlers, for example those used for loading platform
 310      * classes or classes on the class path, may not be overridden. The details
 311      * of such restrictions, and when those restrictions apply (during
 312      * initialization of the runtime for example), are implementation specific
 313      * and therefore not specified
 314      *
 315      * <p>No validation of the inputs is performed by this constructor.
 316      *
 317      * @param      protocol   the name of the protocol to use.
 318      * @param      host       the name of the host.
 319      * @param      port       the port number on the host.
 320      * @param      file       the file on the host
 321      * @exception  MalformedURLException  if an unknown protocol or the port
 322      *                  is a negative number other than -1
 323      * @see        java.lang.System#getProperty(java.lang.String)
 324      * @see        java.net.URL#setURLStreamHandlerFactory(
 325      *                  java.net.URLStreamHandlerFactory)
 326      * @see        java.net.URLStreamHandler
 327      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 328      *                  java.lang.String)
 329      */
 330     public URL(String protocol, String host, int port, String file)
 331         throws MalformedURLException
 332     {
 333         this(protocol, host, port, file, null);
 334     }
 335 
 336     /**
 337      * Creates a URL from the specified {@code protocol}
 338      * name, {@code host} name, and {@code file} name. The
 339      * default port for the specified protocol is used.
 340      * <p>
 341      * This constructor is equivalent to the four-argument
 342      * constructor with the only difference of using the
 343      * default port for the specified protocol.
 344      *
 345      * No validation of the inputs is performed by this constructor.
 346      *
 347      * @param      protocol   the name of the protocol to use.
 348      * @param      host       the name of the host.
 349      * @param      file       the file on the host.
 350      * @exception  MalformedURLException  if an unknown protocol is specified.
 351      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 352      *                  int, java.lang.String)
 353      */
 354     public URL(String protocol, String host, String file)
 355             throws MalformedURLException {
 356         this(protocol, host, -1, file);
 357     }
 358 
 359     /**
 360      * Creates a {@code URL} object from the specified
 361      * {@code protocol}, {@code host}, {@code port}
 362      * number, {@code file}, and {@code handler}. Specifying
 363      * a {@code port} number of {@code -1} indicates that
 364      * the URL should use the default port for the protocol. Specifying
 365      * a {@code handler} of {@code null} indicates that the URL
 366      * should use a default stream handler for the protocol, as outlined
 367      * for:
 368      *     java.net.URL#URL(java.lang.String, java.lang.String, int,
 369      *                      java.lang.String)
 370      *
 371      * <p>If the handler is not null and there is a security manager,
 372      * the security manager's {@code checkPermission}
 373      * method is called with a
 374      * {@code NetPermission("specifyStreamHandler")} permission.
 375      * This may result in a SecurityException.
 376      *
 377      * No validation of the inputs is performed by this constructor.
 378      *
 379      * @param      protocol   the name of the protocol to use.
 380      * @param      host       the name of the host.
 381      * @param      port       the port number on the host.
 382      * @param      file       the file on the host
 383      * @param      handler    the stream handler for the URL.
 384      * @exception  MalformedURLException  if an unknown protocol or the port
 385                         is a negative number other than -1
 386      * @exception  SecurityException
 387      *        if a security manager exists and its
 388      *        {@code checkPermission} method doesn't allow
 389      *        specifying a stream handler explicitly.
 390      * @see        java.lang.System#getProperty(java.lang.String)
 391      * @see        java.net.URL#setURLStreamHandlerFactory(
 392      *                  java.net.URLStreamHandlerFactory)
 393      * @see        java.net.URLStreamHandler
 394      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 395      *                  java.lang.String)
 396      * @see        SecurityManager#checkPermission
 397      * @see        java.net.NetPermission
 398      */
 399     public URL(String protocol, String host, int port, String file,
 400                URLStreamHandler handler) throws MalformedURLException {
 401         if (handler != null) {
 402             SecurityManager sm = System.getSecurityManager();
 403             if (sm != null) {
 404                 // check for permission to specify a handler
 405                 checkSpecifyHandler(sm);
 406             }
 407         }
 408 
 409         protocol = protocol.toLowerCase(Locale.ROOT);
 410         this.protocol = protocol;
 411         if (host != null) {
 412 
 413             /**
 414              * if host is a literal IPv6 address,
 415              * we will make it conform to RFC 2732
 416              */
 417             if (host.indexOf(':') >= 0 && !host.startsWith("[")) {
 418                 host = "["+host+"]";
 419             }
 420             this.host = host;
 421 
 422             if (port < -1) {
 423                 throw new MalformedURLException("Invalid port number :" +
 424                                                     port);
 425             }
 426             this.port = port;
 427             authority = (port == -1) ? host : host + ":" + port;
 428         }
 429 
 430         Parts parts = new Parts(file);
 431         path = parts.getPath();
 432         query = parts.getQuery();
 433 
 434         if (query != null) {
 435             this.file = path + "?" + query;
 436         } else {
 437             this.file = path;
 438         }
 439         ref = parts.getRef();
 440 
 441         // Note: we don't do validation of the URL here. Too risky to change
 442         // right now, but worth considering for future reference. -br
 443         if (handler == null &&
 444             (handler = getURLStreamHandler(protocol)) == null) {
 445             throw new MalformedURLException("unknown protocol: " + protocol);
 446         }
 447         this.handler = handler;
 448     }
 449 
 450     /**
 451      * Creates a {@code URL} object from the {@code String}
 452      * representation.
 453      * <p>
 454      * This constructor is equivalent to a call to the two-argument
 455      * constructor with a {@code null} first argument.
 456      *
 457      * @param      spec   the {@code String} to parse as a URL.
 458      * @exception  MalformedURLException  if no protocol is specified, or an
 459      *               unknown protocol is found, or {@code spec} is {@code null},
 460      *               or the parsed URL fails to comply with the specific syntax
 461      *               of the associated protocol.
 462      * @see        java.net.URL#URL(java.net.URL, java.lang.String)
 463      */
 464     public URL(String spec) throws MalformedURLException {
 465         this(null, spec);
 466     }
 467 
 468     /**
 469      * Creates a URL by parsing the given spec within a specified context.
 470      *
 471      * The new URL is created from the given context URL and the spec
 472      * argument as described in
 473      * RFC2396 &quot;Uniform Resource Identifiers : Generic * Syntax&quot; :
 474      * <blockquote><pre>
 475      *          &lt;scheme&gt;://&lt;authority&gt;&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;
 476      * </pre></blockquote>
 477      * The reference is parsed into the scheme, authority, path, query and
 478      * fragment parts. If the path component is empty and the scheme,
 479      * authority, and query components are undefined, then the new URL is a
 480      * reference to the current document. Otherwise, the fragment and query
 481      * parts present in the spec are used in the new URL.
 482      * <p>
 483      * If the scheme component is defined in the given spec and does not match
 484      * the scheme of the context, then the new URL is created as an absolute
 485      * URL based on the spec alone. Otherwise the scheme component is inherited
 486      * from the context URL.
 487      * <p>
 488      * If the authority component is present in the spec then the spec is
 489      * treated as absolute and the spec authority and path will replace the
 490      * context authority and path. If the authority component is absent in the
 491      * spec then the authority of the new URL will be inherited from the
 492      * context.
 493      * <p>
 494      * If the spec's path component begins with a slash character
 495      * &quot;/&quot; then the
 496      * path is treated as absolute and the spec path replaces the context path.
 497      * <p>
 498      * Otherwise, the path is treated as a relative path and is appended to the
 499      * context path, as described in RFC2396. Also, in this case,
 500      * the path is canonicalized through the removal of directory
 501      * changes made by occurrences of &quot;..&quot; and &quot;.&quot;.
 502      * <p>
 503      * For a more detailed description of URL parsing, refer to RFC2396.
 504      *
 505      * @param      context   the context in which to parse the specification.
 506      * @param      spec      the {@code String} to parse as a URL.
 507      * @exception  MalformedURLException  if no protocol is specified, or an
 508      *               unknown protocol is found, or {@code spec} is {@code null},
 509      *               or the parsed URL fails to comply with the specific syntax
 510      *               of the associated protocol.
 511      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 512      *                  int, java.lang.String)
 513      * @see        java.net.URLStreamHandler
 514      * @see        java.net.URLStreamHandler#parseURL(java.net.URL,
 515      *                  java.lang.String, int, int)
 516      */
 517     public URL(URL context, String spec) throws MalformedURLException {
 518         this(context, spec, null);
 519     }
 520 
 521     /**
 522      * Creates a URL by parsing the given spec with the specified handler
 523      * within a specified context. If the handler is null, the parsing
 524      * occurs as with the two argument constructor.
 525      *
 526      * @param      context   the context in which to parse the specification.
 527      * @param      spec      the {@code String} to parse as a URL.
 528      * @param      handler   the stream handler for the URL.
 529      * @exception  MalformedURLException  if no protocol is specified, or an
 530      *               unknown protocol is found, or {@code spec} is {@code null},
 531      *               or the parsed URL fails to comply with the specific syntax
 532      *               of the associated protocol.
 533      * @exception  SecurityException
 534      *        if a security manager exists and its
 535      *        {@code checkPermission} method doesn't allow
 536      *        specifying a stream handler.
 537      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 538      *                  int, java.lang.String)
 539      * @see        java.net.URLStreamHandler
 540      * @see        java.net.URLStreamHandler#parseURL(java.net.URL,
 541      *                  java.lang.String, int, int)
 542      */
 543     public URL(URL context, String spec, URLStreamHandler handler)
 544         throws MalformedURLException
 545     {
 546         String original = spec;
 547         int i, limit, c;
 548         int start = 0;
 549         String newProtocol = null;
 550         boolean aRef=false;
 551         boolean isRelative = false;
 552 
 553         // Check for permission to specify a handler
 554         if (handler != null) {
 555             SecurityManager sm = System.getSecurityManager();
 556             if (sm != null) {
 557                 checkSpecifyHandler(sm);
 558             }
 559         }
 560 
 561         try {
 562             limit = spec.length();
 563             while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) {
 564                 limit--;        //eliminate trailing whitespace
 565             }
 566             while ((start < limit) && (spec.charAt(start) <= ' ')) {
 567                 start++;        // eliminate leading whitespace
 568             }
 569 
 570             if (spec.regionMatches(true, start, "url:", 0, 4)) {
 571                 start += 4;
 572             }
 573             if (start < spec.length() && spec.charAt(start) == '#') {
 574                 /* we're assuming this is a ref relative to the context URL.
 575                  * This means protocols cannot start w/ '#', but we must parse
 576                  * ref URL's like: "hello:there" w/ a ':' in them.
 577                  */
 578                 aRef=true;
 579             }
 580             for (i = start ; !aRef && (i < limit) &&
 581                      ((c = spec.charAt(i)) != '/') ; i++) {
 582                 if (c == ':') {
 583                     String s = spec.substring(start, i).toLowerCase(Locale.ROOT);
 584                     if (isValidProtocol(s)) {
 585                         newProtocol = s;
 586                         start = i + 1;
 587                     }
 588                     break;
 589                 }
 590             }
 591 
 592             // Only use our context if the protocols match.
 593             protocol = newProtocol;
 594             if ((context != null) && ((newProtocol == null) ||
 595                             newProtocol.equalsIgnoreCase(context.protocol))) {
 596                 // inherit the protocol handler from the context
 597                 // if not specified to the constructor
 598                 if (handler == null) {
 599                     handler = context.handler;
 600                 }
 601 
 602                 // If the context is a hierarchical URL scheme and the spec
 603                 // contains a matching scheme then maintain backwards
 604                 // compatibility and treat it as if the spec didn't contain
 605                 // the scheme; see 5.2.3 of RFC2396
 606                 if (context.path != null && context.path.startsWith("/"))
 607                     newProtocol = null;
 608 
 609                 if (newProtocol == null) {
 610                     protocol = context.protocol;
 611                     authority = context.authority;
 612                     userInfo = context.userInfo;
 613                     host = context.host;
 614                     port = context.port;
 615                     file = context.file;
 616                     path = context.path;
 617                     isRelative = true;
 618                 }
 619             }
 620 
 621             if (protocol == null) {
 622                 throw new MalformedURLException("no protocol: "+original);
 623             }
 624 
 625             // Get the protocol handler if not specified or the protocol
 626             // of the context could not be used
 627             if (handler == null &&
 628                 (handler = getURLStreamHandler(protocol)) == null) {
 629                 throw new MalformedURLException("unknown protocol: "+protocol);
 630             }
 631 
 632             this.handler = handler;
 633 
 634             i = spec.indexOf('#', start);
 635             if (i >= 0) {
 636                 ref = spec.substring(i + 1, limit);
 637                 limit = i;
 638             }
 639 
 640             /*
 641              * Handle special case inheritance of query and fragment
 642              * implied by RFC2396 section 5.2.2.
 643              */
 644             if (isRelative && start == limit) {
 645                 query = context.query;
 646                 if (ref == null) {
 647                     ref = context.ref;
 648                 }
 649             }
 650 
 651             handler.parseURL(this, spec, start, limit);
 652 
 653         } catch(MalformedURLException e) {
 654             throw e;
 655         } catch(Exception e) {
 656             MalformedURLException exception = new MalformedURLException(e.getMessage());
 657             exception.initCause(e);
 658             throw exception;
 659         }
 660     }
 661 
 662     /**
 663      * Creates a URL from a URI, as if by invoking {@code uri.toURL()}.
 664      *
 665      * @see java.net.URI#toURL()
 666      */
 667     static URL fromURI(URI uri) throws MalformedURLException {
 668         if (!uri.isAbsolute()) {
 669             throw new IllegalArgumentException("URI is not absolute");
 670         }
 671         String protocol = uri.getScheme();
 672 
 673         // In general we need to go via Handler.parseURL, but for the jrt
 674         // protocol we enforce that the Handler is not overrideable and can
 675         // optimize URI to URL conversion.
 676         //
 677         // Case-sensitive comparison for performance; malformed protocols will
 678         // be handled correctly by the slow path.
 679         if (protocol.equals("jrt") && !uri.isOpaque()
 680                 && uri.getRawFragment() == null) {
 681 
 682             String query = uri.getRawQuery();
 683             String path = uri.getRawPath();
 684             String file = (query == null) ? path : path + "?" + query;
 685 
 686             // URL represent undefined host as empty string while URI use null
 687             String host = uri.getHost();
 688             if (host == null) {
 689                 host = "";
 690             }
 691 
 692             int port = uri.getPort();
 693 
 694             return new URL("jrt", host, port, file, null);
 695         } else {
 696             return new URL((URL)null, uri.toString(), null);
 697         }
 698     }
 699 
 700     /*
 701      * Returns true if specified string is a valid protocol name.
 702      */
 703     private boolean isValidProtocol(String protocol) {
 704         int len = protocol.length();
 705         if (len < 1)
 706             return false;
 707         char c = protocol.charAt(0);
 708         if (!Character.isLetter(c))
 709             return false;
 710         for (int i = 1; i < len; i++) {
 711             c = protocol.charAt(i);
 712             if (!Character.isLetterOrDigit(c) && c != '.' && c != '+' &&
 713                 c != '-') {
 714                 return false;
 715             }
 716         }
 717         return true;
 718     }
 719 
 720     /*
 721      * Checks for permission to specify a stream handler.
 722      */
 723     private void checkSpecifyHandler(SecurityManager sm) {
 724         sm.checkPermission(SecurityConstants.SPECIFY_HANDLER_PERMISSION);
 725     }
 726 
 727     /**
 728      * Sets the fields of the URL. This is not a public method so that
 729      * only URLStreamHandlers can modify URL fields. URLs are
 730      * otherwise constant.
 731      *
 732      * @param protocol the name of the protocol to use
 733      * @param host the name of the host
 734        @param port the port number on the host
 735      * @param file the file on the host
 736      * @param ref the internal reference in the URL
 737      */
 738     void set(String protocol, String host, int port,
 739              String file, String ref) {
 740         synchronized (this) {
 741             this.protocol = protocol;
 742             this.host = host;
 743             authority = port == -1 ? host : host + ":" + port;
 744             this.port = port;
 745             this.file = file;
 746             this.ref = ref;
 747             /* This is very important. We must recompute this after the
 748              * URL has been changed. */
 749             hashCode = -1;
 750             hostAddress = null;
 751             int q = file.lastIndexOf('?');
 752             if (q != -1) {
 753                 query = file.substring(q+1);
 754                 path = file.substring(0, q);
 755             } else
 756                 path = file;
 757         }
 758     }
 759 
 760     /**
 761      * Sets the specified 8 fields of the URL. This is not a public method so
 762      * that only URLStreamHandlers can modify URL fields. URLs are otherwise
 763      * constant.
 764      *
 765      * @param protocol the name of the protocol to use
 766      * @param host the name of the host
 767      * @param port the port number on the host
 768      * @param authority the authority part for the url
 769      * @param userInfo the username and password
 770      * @param path the file on the host
 771      * @param ref the internal reference in the URL
 772      * @param query the query part of this URL
 773      * @since 1.3
 774      */
 775     void set(String protocol, String host, int port,
 776              String authority, String userInfo, String path,
 777              String query, String ref) {
 778         synchronized (this) {
 779             this.protocol = protocol;
 780             this.host = host;
 781             this.port = port;
 782             this.file = query == null ? path : path + "?" + query;
 783             this.userInfo = userInfo;
 784             this.path = path;
 785             this.ref = ref;
 786             /* This is very important. We must recompute this after the
 787              * URL has been changed. */
 788             hashCode = -1;
 789             hostAddress = null;
 790             this.query = query;
 791             this.authority = authority;
 792         }
 793     }
 794 
 795     /**
 796      * Gets the query part of this {@code URL}.
 797      *
 798      * @return  the query part of this {@code URL},
 799      * or <CODE>null</CODE> if one does not exist
 800      * @since 1.3
 801      */
 802     public String getQuery() {
 803         return query;
 804     }
 805 
 806     /**
 807      * Gets the path part of this {@code URL}.
 808      *
 809      * @return  the path part of this {@code URL}, or an
 810      * empty string if one does not exist
 811      * @since 1.3
 812      */
 813     public String getPath() {
 814         return path;
 815     }
 816 
 817     /**
 818      * Gets the userInfo part of this {@code URL}.
 819      *
 820      * @return  the userInfo part of this {@code URL}, or
 821      * <CODE>null</CODE> if one does not exist
 822      * @since 1.3
 823      */
 824     public String getUserInfo() {
 825         return userInfo;
 826     }
 827 
 828     /**
 829      * Gets the authority part of this {@code URL}.
 830      *
 831      * @return  the authority part of this {@code URL}
 832      * @since 1.3
 833      */
 834     public String getAuthority() {
 835         return authority;
 836     }
 837 
 838     /**
 839      * Gets the port number of this {@code URL}.
 840      *
 841      * @return  the port number, or -1 if the port is not set
 842      */
 843     public int getPort() {
 844         return port;
 845     }
 846 
 847     /**
 848      * Gets the default port number of the protocol associated
 849      * with this {@code URL}. If the URL scheme or the URLStreamHandler
 850      * for the URL do not define a default port number,
 851      * then -1 is returned.
 852      *
 853      * @return  the port number
 854      * @since 1.4
 855      */
 856     public int getDefaultPort() {
 857         return handler.getDefaultPort();
 858     }
 859 
 860     /**
 861      * Gets the protocol name of this {@code URL}.
 862      *
 863      * @return  the protocol of this {@code URL}.
 864      */
 865     public String getProtocol() {
 866         return protocol;
 867     }
 868 
 869     /**
 870      * Gets the host name of this {@code URL}, if applicable.
 871      * The format of the host conforms to RFC 2732, i.e. for a
 872      * literal IPv6 address, this method will return the IPv6 address
 873      * enclosed in square brackets ({@code '['} and {@code ']'}).
 874      *
 875      * @return  the host name of this {@code URL}.
 876      */
 877     public String getHost() {
 878         return host;
 879     }
 880 
 881     /**
 882      * Gets the file name of this {@code URL}.
 883      * The returned file portion will be
 884      * the same as <CODE>getPath()</CODE>, plus the concatenation of
 885      * the value of <CODE>getQuery()</CODE>, if any. If there is
 886      * no query portion, this method and <CODE>getPath()</CODE> will
 887      * return identical results.
 888      *
 889      * @return  the file name of this {@code URL},
 890      * or an empty string if one does not exist
 891      */
 892     public String getFile() {
 893         return file;
 894     }
 895 
 896     /**
 897      * Gets the anchor (also known as the "reference") of this
 898      * {@code URL}.
 899      *
 900      * @return  the anchor (also known as the "reference") of this
 901      *          {@code URL}, or <CODE>null</CODE> if one does not exist
 902      */
 903     public String getRef() {
 904         return ref;
 905     }
 906 
 907     /**
 908      * Compares this URL for equality with another object.<p>
 909      *
 910      * If the given object is not a URL then this method immediately returns
 911      * {@code false}.<p>
 912      *
 913      * Two URL objects are equal if they have the same protocol, reference
 914      * equivalent hosts, have the same port number on the host, and the same
 915      * file and fragment of the file.<p>
 916      *
 917      * Two hosts are considered equivalent if both host names can be resolved
 918      * into the same IP addresses; else if either host name can't be
 919      * resolved, the host names must be equal without regard to case; or both
 920      * host names equal to null.<p>
 921      *
 922      * Since hosts comparison requires name resolution, this operation is a
 923      * blocking operation. <p>
 924      *
 925      * Note: The defined behavior for {@code equals} is known to
 926      * be inconsistent with virtual hosting in HTTP.
 927      *
 928      * @param   obj   the URL to compare against.
 929      * @return  {@code true} if the objects are the same;
 930      *          {@code false} otherwise.
 931      */
 932     public boolean equals(Object obj) {
 933         if (!(obj instanceof URL))
 934             return false;
 935         URL u2 = (URL)obj;
 936 
 937         return handler.equals(this, u2);
 938     }
 939 
 940     /**
 941      * Creates an integer suitable for hash table indexing.<p>
 942      *
 943      * The hash code is based upon all the URL components relevant for URL
 944      * comparison. As such, this operation is a blocking operation.
 945      *
 946      * @return  a hash code for this {@code URL}.
 947      */
 948     public synchronized int hashCode() {
 949         if (hashCode != -1)
 950             return hashCode;
 951 
 952         hashCode = handler.hashCode(this);
 953         return hashCode;
 954     }
 955 
 956     /**
 957      * Compares two URLs, excluding the fragment component.<p>
 958      *
 959      * Returns {@code true} if this {@code URL} and the
 960      * {@code other} argument are equal without taking the
 961      * fragment component into consideration.
 962      *
 963      * @param   other   the {@code URL} to compare against.
 964      * @return  {@code true} if they reference the same remote object;
 965      *          {@code false} otherwise.
 966      */
 967     public boolean sameFile(URL other) {
 968         return handler.sameFile(this, other);
 969     }
 970 
 971     /**
 972      * Constructs a string representation of this {@code URL}. The
 973      * string is created by calling the {@code toExternalForm}
 974      * method of the stream protocol handler for this object.
 975      *
 976      * @return  a string representation of this object.
 977      * @see     java.net.URL#URL(java.lang.String, java.lang.String, int,
 978      *                  java.lang.String)
 979      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 980      */
 981     public String toString() {
 982         return toExternalForm();
 983     }
 984 
 985     /**
 986      * Constructs a string representation of this {@code URL}. The
 987      * string is created by calling the {@code toExternalForm}
 988      * method of the stream protocol handler for this object.
 989      *
 990      * @return  a string representation of this object.
 991      * @see     java.net.URL#URL(java.lang.String, java.lang.String,
 992      *                  int, java.lang.String)
 993      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 994      */
 995     public String toExternalForm() {
 996         return handler.toExternalForm(this);
 997     }
 998 
 999     /**
1000      * Returns a {@link java.net.URI} equivalent to this URL.
1001      * This method functions in the same way as {@code new URI (this.toString())}.
1002      * <p>Note, any URL instance that complies with RFC 2396 can be converted
1003      * to a URI. However, some URLs that are not strictly in compliance
1004      * can not be converted to a URI.
1005      *
1006      * @exception URISyntaxException if this URL is not formatted strictly according to
1007      *            to RFC2396 and cannot be converted to a URI.
1008      *
1009      * @return    a URI instance equivalent to this URL.
1010      * @since 1.5
1011      */
1012     public URI toURI() throws URISyntaxException {
1013         return new URI (toString());
1014     }
1015 
1016     /**
1017      * Returns a {@link java.net.URLConnection URLConnection} instance that
1018      * represents a connection to the remote object referred to by the
1019      * {@code URL}.
1020      *
1021      * <P>A new instance of {@linkplain java.net.URLConnection URLConnection} is
1022      * created every time when invoking the
1023      * {@linkplain java.net.URLStreamHandler#openConnection(URL)
1024      * URLStreamHandler.openConnection(URL)} method of the protocol handler for
1025      * this URL.</P>
1026      *
1027      * <P>It should be noted that a URLConnection instance does not establish
1028      * the actual network connection on creation. This will happen only when
1029      * calling {@linkplain java.net.URLConnection#connect() URLConnection.connect()}.</P>
1030      *
1031      * <P>If for the URL's protocol (such as HTTP or JAR), there
1032      * exists a public, specialized URLConnection subclass belonging
1033      * to one of the following packages or one of their subpackages:
1034      * java.lang, java.io, java.util, java.net, the connection
1035      * returned will be of that subclass. For example, for HTTP an
1036      * HttpURLConnection will be returned, and for JAR a
1037      * JarURLConnection will be returned.</P>
1038      *
1039      * @return     a {@link java.net.URLConnection URLConnection} linking
1040      *             to the URL.
1041      * @exception  IOException  if an I/O exception occurs.
1042      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1043      *             int, java.lang.String)
1044      */
1045     public URLConnection openConnection() throws java.io.IOException {
1046         return handler.openConnection(this);
1047     }
1048 
1049     /**
1050      * Same as {@link #openConnection()}, except that the connection will be
1051      * made through the specified proxy; Protocol handlers that do not
1052      * support proxing will ignore the proxy parameter and make a
1053      * normal connection.
1054      *
1055      * Invoking this method preempts the system's default
1056      * {@link java.net.ProxySelector ProxySelector} settings.
1057      *
1058      * @param      proxy the Proxy through which this connection
1059      *             will be made. If direct connection is desired,
1060      *             Proxy.NO_PROXY should be specified.
1061      * @return     a {@code URLConnection} to the URL.
1062      * @exception  IOException  if an I/O exception occurs.
1063      * @exception  SecurityException if a security manager is present
1064      *             and the caller doesn't have permission to connect
1065      *             to the proxy.
1066      * @exception  IllegalArgumentException will be thrown if proxy is null,
1067      *             or proxy has the wrong type
1068      * @exception  UnsupportedOperationException if the subclass that
1069      *             implements the protocol handler doesn't support
1070      *             this method.
1071      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1072      *             int, java.lang.String)
1073      * @see        java.net.URLConnection
1074      * @see        java.net.URLStreamHandler#openConnection(java.net.URL,
1075      *             java.net.Proxy)
1076      * @since      1.5
1077      */
1078     public URLConnection openConnection(Proxy proxy)
1079         throws java.io.IOException {
1080         if (proxy == null) {
1081             throw new IllegalArgumentException("proxy can not be null");
1082         }
1083 
1084         // Create a copy of Proxy as a security measure
1085         Proxy p = proxy == Proxy.NO_PROXY ? Proxy.NO_PROXY : sun.net.ApplicationProxy.create(proxy);
1086         SecurityManager sm = System.getSecurityManager();
1087         if (p.type() != Proxy.Type.DIRECT && sm != null) {
1088             InetSocketAddress epoint = (InetSocketAddress) p.address();
1089             if (epoint.isUnresolved())
1090                 sm.checkConnect(epoint.getHostName(), epoint.getPort());
1091             else
1092                 sm.checkConnect(epoint.getAddress().getHostAddress(),
1093                                 epoint.getPort());
1094         }
1095         return handler.openConnection(this, p);
1096     }
1097 
1098     /**
1099      * Opens a connection to this {@code URL} and returns an
1100      * {@code InputStream} for reading from that connection. This
1101      * method is a shorthand for:
1102      * <blockquote><pre>
1103      *     openConnection().getInputStream()
1104      * </pre></blockquote>
1105      *
1106      * @return     an input stream for reading from the URL connection.
1107      * @exception  IOException  if an I/O exception occurs.
1108      * @see        java.net.URL#openConnection()
1109      * @see        java.net.URLConnection#getInputStream()
1110      */
1111     public final InputStream openStream() throws java.io.IOException {
1112         return openConnection().getInputStream();
1113     }
1114 
1115     /**
1116      * Gets the contents of this URL. This method is a shorthand for:
1117      * <blockquote><pre>
1118      *     openConnection().getContent()
1119      * </pre></blockquote>
1120      *
1121      * @return     the contents of this URL.
1122      * @exception  IOException  if an I/O exception occurs.
1123      * @see        java.net.URLConnection#getContent()
1124      */
1125     public final Object getContent() throws java.io.IOException {
1126         return openConnection().getContent();
1127     }
1128 
1129     /**
1130      * Gets the contents of this URL. This method is a shorthand for:
1131      * <blockquote><pre>
1132      *     openConnection().getContent(classes)
1133      * </pre></blockquote>
1134      *
1135      * @param classes an array of Java types
1136      * @return     the content object of this URL that is the first match of
1137      *               the types specified in the classes array.
1138      *               null if none of the requested types are supported.
1139      * @exception  IOException  if an I/O exception occurs.
1140      * @see        java.net.URLConnection#getContent(Class[])
1141      * @since 1.3
1142      */
1143     public final Object getContent(Class<?>[] classes)
1144     throws java.io.IOException {
1145         return openConnection().getContent(classes);
1146     }
1147 
1148     /**
1149      * The URLStreamHandler factory.
1150      */
1151     private static volatile URLStreamHandlerFactory factory;
1152 
1153     /**
1154      * Sets an application's {@code URLStreamHandlerFactory}.
1155      * This method can be called at most once in a given Java Virtual
1156      * Machine.
1157      *
1158      *<p> The {@code URLStreamHandlerFactory} instance is used to
1159      *construct a stream protocol handler from a protocol name.
1160      *
1161      * <p> If there is a security manager, this method first calls
1162      * the security manager's {@code checkSetFactory} method
1163      * to ensure the operation is allowed.
1164      * This could result in a SecurityException.
1165      *
1166      * @param      fac   the desired factory.
1167      * @exception  Error  if the application has already set a factory.
1168      * @exception  SecurityException  if a security manager exists and its
1169      *             {@code checkSetFactory} method doesn't allow
1170      *             the operation.
1171      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1172      *             int, java.lang.String)
1173      * @see        java.net.URLStreamHandlerFactory
1174      * @see        SecurityManager#checkSetFactory
1175      */
1176     public static void setURLStreamHandlerFactory(URLStreamHandlerFactory fac) {
1177         synchronized (streamHandlerLock) {
1178             if (factory != null) {
1179                 throw new Error("factory already defined");
1180             }
1181             SecurityManager security = System.getSecurityManager();
1182             if (security != null) {
1183                 security.checkSetFactory();
1184             }
1185             handlers.clear();
1186 
1187             // safe publication of URLStreamHandlerFactory with volatile write
1188             factory = fac;
1189         }
1190     }
1191 
1192     private static final URLStreamHandlerFactory defaultFactory = new DefaultFactory();
1193 
1194     private static class DefaultFactory implements URLStreamHandlerFactory {
1195         private static String PREFIX = "sun.net.www.protocol";
1196 
1197         public URLStreamHandler createURLStreamHandler(String protocol) {
1198             String name = PREFIX + "." + protocol + ".Handler";
1199             try {
1200                 Class<?> c = Class.forName(name);
1201                 return (URLStreamHandler)c.newInstance();
1202             } catch (ClassNotFoundException x) {
1203                 // ignore
1204             } catch (Exception e) {
1205                 // For compatibility, all Exceptions are ignored.
1206                 // any number of exceptions can get thrown here
1207             }
1208             return null;
1209         }
1210     }
1211 
1212     private static URLStreamHandler lookupViaProperty(String protocol) {
1213         String packagePrefixList = java.security.AccessController.doPrivileged(
1214                 new PrivilegedAction<>() {
1215                     public String run() {
1216                         return System.getProperty(protocolPathProp, null);
1217                     }
1218                 });
1219         if (packagePrefixList == null) {
1220             // not set
1221             return null;
1222         }
1223 
1224         String[] packagePrefixes = packagePrefixList.split("\\|");
1225         URLStreamHandler handler = null;
1226         for (int i=0; handler == null && i<packagePrefixes.length; i++) {
1227             String packagePrefix = packagePrefixes[i].trim();
1228             try {
1229                 String clsName = packagePrefix + "." + protocol + ".Handler";
1230                 Class<?> cls = null;
1231                 try {
1232                     cls = Class.forName(clsName);
1233                 } catch (ClassNotFoundException e) {
1234                     ClassLoader cl = ClassLoader.getSystemClassLoader();
1235                     if (cl != null) {
1236                         cls = cl.loadClass(clsName);
1237                     }
1238                 }
1239                 if (cls != null) {
1240                     handler = (URLStreamHandler)cls.newInstance();
1241                 }
1242             } catch (Exception e) {
1243                 // any number of exceptions can get thrown here
1244             }
1245         }
1246         return handler;
1247     }
1248 
1249     private static Iterator<URLStreamHandlerProvider> providers() {
1250         return new Iterator<>() {
1251 
1252             ClassLoader cl = ClassLoader.getSystemClassLoader();
1253             ServiceLoader<URLStreamHandlerProvider> sl =
1254                     ServiceLoader.load(URLStreamHandlerProvider.class, cl);
1255             Iterator<URLStreamHandlerProvider> i = sl.iterator();
1256 
1257             URLStreamHandlerProvider next = null;
1258 
1259             private boolean getNext() {
1260                 while (next == null) {
1261                     try {
1262                         if (!i.hasNext())
1263                             return false;
1264                         next = i.next();
1265                     } catch (ServiceConfigurationError sce) {
1266                         if (sce.getCause() instanceof SecurityException) {
1267                             // Ignore security exceptions
1268                             continue;
1269                         }
1270                         throw sce;
1271                     }
1272                 }
1273                 return true;
1274             }
1275 
1276             public boolean hasNext() {
1277                 return getNext();
1278             }
1279 
1280             public URLStreamHandlerProvider next() {
1281                 if (!getNext())
1282                     throw new NoSuchElementException();
1283                 URLStreamHandlerProvider n = next;
1284                 next = null;
1285                 return n;
1286             }
1287         };
1288     }
1289 
1290     // Thread-local gate to prevent recursive provider lookups
1291     private static ThreadLocal<Object> gate = new ThreadLocal<>();
1292 
1293     private static URLStreamHandler lookupViaProviders(final String protocol) {
1294         if (gate.get() != null)
1295             throw new Error("Circular loading of URL stream handler providers detected");
1296 
1297         gate.set(gate);
1298         try {
1299             return AccessController.doPrivileged(
1300                 new PrivilegedAction<>() {
1301                     public URLStreamHandler run() {
1302                         Iterator<URLStreamHandlerProvider> itr = providers();
1303                         while (itr.hasNext()) {
1304                             URLStreamHandlerProvider f = itr.next();
1305                             URLStreamHandler h = f.createURLStreamHandler(protocol);
1306                             if (h != null)
1307                                 return h;
1308                         }
1309                         return null;
1310                     }
1311                 });
1312         } finally {
1313             gate.set(null);
1314         }
1315     }
1316 
1317 
1318     /**
1319      * Non-overrideable protocols: "jrt" and "file"
1320      *
1321      * Character-based comparison for performance reasons; also ensures
1322      * case-insensitive comparison in a locale-independent fashion.
1323      */
1324     static boolean isOverrideable(String protocol) {
1325         if (protocol.length() == 3) {
1326             if ((Character.toLowerCase(protocol.charAt(0)) == 'j') &&
1327                     (Character.toLowerCase(protocol.charAt(1)) == 'r') &&
1328                     (Character.toLowerCase(protocol.charAt(2)) == 't')) {
1329                 return false;
1330             }
1331         } else if (protocol.length() == 4) {
1332             if ((Character.toLowerCase(protocol.charAt(0)) == 'f') &&
1333                     (Character.toLowerCase(protocol.charAt(1)) == 'i') &&
1334                     (Character.toLowerCase(protocol.charAt(2)) == 'l') &&
1335                     (Character.toLowerCase(protocol.charAt(3)) == 'e')) {
1336                 return false;
1337             }
1338         }
1339         return true;
1340     }
1341 
1342     /**
1343      * A table of protocol handlers.
1344      */
1345     static Hashtable<String,URLStreamHandler> handlers = new Hashtable<>();
1346     private static final Object streamHandlerLock = new Object();
1347 
1348     /**
1349      * Returns the Stream Handler.
1350      * @param protocol the protocol to use
1351      */
1352     static URLStreamHandler getURLStreamHandler(String protocol) {
1353 
1354         URLStreamHandler handler = handlers.get(protocol);
1355 
1356         if (handler != null) {
1357             return handler;
1358         }
1359 
1360         URLStreamHandlerFactory fac;
1361         boolean checkedWithFactory = false;
1362 
1363         if (isOverrideable(protocol) && jdk.internal.misc.VM.isBooted()) {
1364             // Use the factory (if any). Volatile read makes
1365             // URLStreamHandlerFactory appear fully initialized to current thread.
1366             fac = factory;
1367             if (fac != null) {
1368                 handler = fac.createURLStreamHandler(protocol);
1369                 checkedWithFactory = true;
1370             }
1371 
1372             if (handler == null && !protocol.equalsIgnoreCase("jar")) {
1373                 handler = lookupViaProviders(protocol);
1374             }
1375 
1376             if (handler == null) {
1377                 handler = lookupViaProperty(protocol);
1378             }
1379         }
1380 
1381         synchronized (streamHandlerLock) {
1382             if (handler == null) {
1383                 // Try the built-in protocol handler
1384                 handler = defaultFactory.createURLStreamHandler(protocol);
1385             } else {
1386                 URLStreamHandler handler2 = null;
1387 
1388                 // Check again with hashtable just in case another
1389                 // thread created a handler since we last checked
1390                 handler2 = handlers.get(protocol);
1391 
1392                 if (handler2 != null) {
1393                     return handler2;
1394                 }
1395 
1396                 // Check with factory if another thread set a
1397                 // factory since our last check
1398                 if (!checkedWithFactory && (fac = factory) != null) {
1399                     handler2 =  fac.createURLStreamHandler(protocol);
1400                 }
1401 
1402                 if (handler2 != null) {
1403                     // The handler from the factory must be given more
1404                     // importance. Discard the default handler that
1405                     // this thread created.
1406                     handler = handler2;
1407                 }
1408             }
1409 
1410             // Insert this handler into the hashtable
1411             if (handler != null) {
1412                 handlers.put(protocol, handler);
1413             }
1414         }
1415 
1416         return handler;
1417     }
1418 
1419     /**
1420      * @serialField    protocol String
1421      *
1422      * @serialField    host String
1423      *
1424      * @serialField    port int
1425      *
1426      * @serialField    authority String
1427      *
1428      * @serialField    file String
1429      *
1430      * @serialField    ref String
1431      *
1432      * @serialField    hashCode int
1433      *
1434      */
1435     private static final ObjectStreamField[] serialPersistentFields = {
1436         new ObjectStreamField("protocol", String.class),
1437         new ObjectStreamField("host", String.class),
1438         new ObjectStreamField("port", int.class),
1439         new ObjectStreamField("authority", String.class),
1440         new ObjectStreamField("file", String.class),
1441         new ObjectStreamField("ref", String.class),
1442         new ObjectStreamField("hashCode", int.class), };
1443 
1444     /**
1445      * WriteObject is called to save the state of the URL to an
1446      * ObjectOutputStream. The handler is not saved since it is
1447      * specific to this system.
1448      *
1449      * @serialData the default write object value. When read back in,
1450      * the reader must ensure that calling getURLStreamHandler with
1451      * the protocol variable returns a valid URLStreamHandler and
1452      * throw an IOException if it does not.
1453      */
1454     private synchronized void writeObject(java.io.ObjectOutputStream s)
1455         throws IOException
1456     {
1457         s.defaultWriteObject(); // write the fields
1458     }
1459 
1460     /**
1461      * readObject is called to restore the state of the URL from the
1462      * stream.  It reads the components of the URL and finds the local
1463      * stream handler.
1464      */
1465     private synchronized void readObject(java.io.ObjectInputStream s)
1466             throws IOException, ClassNotFoundException {
1467         GetField gf = s.readFields();
1468         String protocol = (String)gf.get("protocol", null);
1469         if (getURLStreamHandler(protocol) == null) {
1470             throw new IOException("unknown protocol: " + protocol);
1471         }
1472         String host = (String)gf.get("host", null);
1473         int port = gf.get("port", -1);
1474         String authority = (String)gf.get("authority", null);
1475         String file = (String)gf.get("file", null);
1476         String ref = (String)gf.get("ref", null);
1477         int hashCode = gf.get("hashCode", -1);
1478         if (authority == null
1479                 && ((host != null && host.length() > 0) || port != -1)) {
1480             if (host == null)
1481                 host = "";
1482             authority = (port == -1) ? host : host + ":" + port;
1483         }
1484         tempState = new UrlDeserializedState(protocol, host, port, authority,
1485                file, ref, hashCode);
1486     }
1487 
1488     /**
1489      * Replaces the de-serialized object with an URL object.
1490      *
1491      * @return a newly created object from deserialized data
1492      *
1493      * @throws ObjectStreamException if a new object replacing this
1494      * object could not be created
1495      */
1496 
1497    private Object readResolve() throws ObjectStreamException {
1498 
1499         URLStreamHandler handler = null;
1500         // already been checked in readObject
1501         handler = getURLStreamHandler(tempState.getProtocol());
1502 
1503         URL replacementURL = null;
1504         if (isBuiltinStreamHandler(handler.getClass().getName())) {
1505             replacementURL = fabricateNewURL();
1506         } else {
1507             replacementURL = setDeserializedFields(handler);
1508         }
1509         return replacementURL;
1510     }
1511 
1512     private URL setDeserializedFields(URLStreamHandler handler) {
1513         URL replacementURL;
1514         String userInfo = null;
1515         String protocol = tempState.getProtocol();
1516         String host = tempState.getHost();
1517         int port = tempState.getPort();
1518         String authority = tempState.getAuthority();
1519         String file = tempState.getFile();
1520         String ref = tempState.getRef();
1521         int hashCode = tempState.getHashCode();
1522 
1523 
1524         // Construct authority part
1525         if (authority == null
1526             && ((host != null && host.length() > 0) || port != -1)) {
1527             if (host == null)
1528                 host = "";
1529             authority = (port == -1) ? host : host + ":" + port;
1530 
1531             // Handle hosts with userInfo in them
1532             int at = host.lastIndexOf('@');
1533             if (at != -1) {
1534                 userInfo = host.substring(0, at);
1535                 host = host.substring(at+1);
1536             }
1537         } else if (authority != null) {
1538             // Construct user info part
1539             int ind = authority.indexOf('@');
1540             if (ind != -1)
1541                 userInfo = authority.substring(0, ind);
1542         }
1543 
1544         // Construct path and query part
1545         String path = null;
1546         String query = null;
1547         if (file != null) {
1548             // Fix: only do this if hierarchical?
1549             int q = file.lastIndexOf('?');
1550             if (q != -1) {
1551                 query = file.substring(q+1);
1552                 path = file.substring(0, q);
1553             } else
1554                 path = file;
1555         }
1556 
1557         if (port == -1) {
1558             port = 0;
1559         }
1560         // Set the object fields.
1561         this.protocol = protocol;
1562         this.host = host;
1563         this.port = port;
1564         this.file = file;
1565         this.authority = authority;
1566         this.ref = ref;
1567         this.hashCode = hashCode;
1568         this.handler = handler;
1569         this.query = query;
1570         this.path = path;
1571         this.userInfo = userInfo;
1572         replacementURL = this;
1573         return replacementURL;
1574     }
1575 
1576     private URL fabricateNewURL()
1577                 throws InvalidObjectException {
1578         // create URL string from deserialized object
1579         URL replacementURL = null;
1580         String urlString = tempState.reconstituteUrlString();
1581 
1582         try {
1583             replacementURL = new URL(urlString);
1584         } catch (MalformedURLException mEx) {
1585             resetState();
1586             InvalidObjectException invoEx = new InvalidObjectException(
1587                     "Malformed URL:  " + urlString);
1588             invoEx.initCause(mEx);
1589             throw invoEx;
1590         }
1591         replacementURL.setSerializedHashCode(tempState.getHashCode());
1592         resetState();
1593         return replacementURL;
1594     }
1595 
1596     private boolean isBuiltinStreamHandler(String handlerClassName) {
1597         return (handlerClassName.startsWith(BUILTIN_HANDLERS_PREFIX));
1598     }
1599 
1600     private void resetState() {
1601         this.protocol = null;
1602         this.host = null;
1603         this.port = -1;
1604         this.file = null;
1605         this.authority = null;
1606         this.ref = null;
1607         this.hashCode = -1;
1608         this.handler = null;
1609         this.query = null;
1610         this.path = null;
1611         this.userInfo = null;
1612         this.tempState = null;
1613     }
1614 
1615     private void setSerializedHashCode(int hc) {
1616         this.hashCode = hc;
1617     }
1618 }
1619 
1620 class Parts {
1621     String path, query, ref;
1622 
1623     Parts(String file) {
1624         int ind = file.indexOf('#');
1625         ref = ind < 0 ? null: file.substring(ind + 1);
1626         file = ind < 0 ? file: file.substring(0, ind);
1627         int q = file.lastIndexOf('?');
1628         if (q != -1) {
1629             query = file.substring(q+1);
1630             path = file.substring(0, q);
1631         } else {
1632             path = file;
1633         }
1634     }
1635 
1636     String getPath() {
1637         return path;
1638     }
1639 
1640     String getQuery() {
1641         return query;
1642     }
1643 
1644     String getRef() {
1645         return ref;
1646     }
1647 }
1648 
1649 final class UrlDeserializedState {
1650     private final String protocol;
1651     private final String host;
1652     private final int port;
1653     private final String authority;
1654     private final String file;
1655     private final String ref;
1656     private final int hashCode;
1657 
1658     public UrlDeserializedState(String protocol,
1659                                 String host, int port,
1660                                 String authority, String file,
1661                                 String ref, int hashCode) {
1662         this.protocol = protocol;
1663         this.host = host;
1664         this.port = port;
1665         this.authority = authority;
1666         this.file = file;
1667         this.ref = ref;
1668         this.hashCode = hashCode;
1669     }
1670 
1671     String getProtocol() {
1672         return protocol;
1673     }
1674 
1675     String getHost() {
1676         return host;
1677     }
1678 
1679     String getAuthority () {
1680         return authority;
1681     }
1682 
1683     int getPort() {
1684         return port;
1685     }
1686 
1687     String getFile () {
1688         return file;
1689     }
1690 
1691     String getRef () {
1692         return ref;
1693     }
1694 
1695     int getHashCode () {
1696         return hashCode;
1697     }
1698 
1699     String reconstituteUrlString() {
1700 
1701         // pre-compute length of StringBuffer
1702         int len = protocol.length() + 1;
1703         if (authority != null && authority.length() > 0)
1704             len += 2 + authority.length();
1705         if (file != null) {
1706             len += file.length();
1707         }
1708         if (ref != null)
1709             len += 1 + ref.length();
1710         StringBuilder result = new StringBuilder(len);
1711         result.append(protocol);
1712         result.append(":");
1713         if (authority != null && authority.length() > 0) {
1714             result.append("//");
1715             result.append(authority);
1716         }
1717         if (file != null) {
1718             result.append(file);
1719         }
1720         if (ref != null) {
1721             result.append("#");
1722             result.append(ref);
1723         }
1724         return result.toString();
1725     }
1726 }
--- EOF ---