1 /*
   2  * Copyright (c) 1995, 2013, 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.security.AccessController;
  31 import java.security.PrivilegedAction;
  32 import java.util.ArrayList;
  33 import java.util.Collection;
  34 import java.util.Collections;
  35 import java.util.Hashtable;
  36 import java.util.List;
  37 import java.util.Objects;
  38 import java.util.ServiceLoader;
  39 import java.util.Set;
  40 import java.util.concurrent.CopyOnWriteArrayList;
  41 
  42 import sun.security.util.SecurityConstants;
  43 
  44 /**
  45  * Class {@code URL} represents a Uniform Resource
  46  * Locator, a pointer to a "resource" on the World
  47  * Wide Web. A resource can be something as simple as a file or a
  48  * directory, or it can be a reference to a more complicated object,
  49  * such as a query to a database or to a search engine. More
  50  * information on the types of URLs and their formats can be found at:
  51  * <a href=
  52  * "http://web.archive.org/web/20051219043731/http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/Demo/url-primer.html">
  53  * <i>Types of URL</i></a>
  54  * <p>
  55  * In general, a URL can be broken into several parts. Consider the
  56  * following example:
  57  * <blockquote><pre>
  58  *     http://www.example.com/docs/resource1.html
  59  * </pre></blockquote>
  60  * <p>
  61  * The URL above indicates that the protocol to use is
  62  * {@code http} (HyperText Transfer Protocol) and that the
  63  * information resides on a host machine named
  64  * {@code www.example.com}. The information on that host
  65  * machine is named {@code /docs/resource1.html}. The exact
  66  * meaning of this name on the host machine is both protocol
  67  * dependent and host dependent. The information normally resides in
  68  * a file, but it could be generated on the fly. This component of
  69  * the URL is called the <i>path</i> component.
  70  * <p>
  71  * A URL can optionally specify a "port", which is the
  72  * port number to which the TCP connection is made on the remote host
  73  * machine. If the port is not specified, the default port for
  74  * the protocol is used instead. For example, the default port for
  75  * {@code http} is {@code 80}. An alternative port could be
  76  * specified as:
  77  * <blockquote><pre>
  78  *     http://www.example.com:1080/docs/resource1.html
  79  * </pre></blockquote>
  80  * <p>
  81  * The syntax of {@code URL} is defined by  <a
  82  * href="http://www.ietf.org/rfc/rfc2396.txt"><i>RFC&nbsp;2396: Uniform
  83  * Resource Identifiers (URI): Generic Syntax</i></a>, amended by <a
  84  * href="http://www.ietf.org/rfc/rfc2732.txt"><i>RFC&nbsp;2732: Format for
  85  * Literal IPv6 Addresses in URLs</i></a>. The Literal IPv6 address format
  86  * also supports scope_ids. The syntax and usage of scope_ids is described
  87  * <a href="Inet6Address.html#scoped">here</a>.
  88  * <p>
  89  * A URL may have appended to it a "fragment", also known
  90  * as a "ref" or a "reference". The fragment is indicated by the sharp
  91  * sign character "#" followed by more characters. For example,
  92  * <blockquote><pre>
  93  *     http://java.sun.com/index.html#chapter1
  94  * </pre></blockquote>
  95  * <p>
  96  * This fragment is not technically part of the URL. Rather, it
  97  * indicates that after the specified resource is retrieved, the
  98  * application is specifically interested in that part of the
  99  * document that has the tag {@code chapter1} attached to it. The
 100  * meaning of a tag is resource specific.
 101  * <p>
 102  * An application can also specify a "relative URL",
 103  * which contains only enough information to reach the resource
 104  * relative to another URL. Relative URLs are frequently used within
 105  * HTML pages. For example, if the contents of the URL:
 106  * <blockquote><pre>
 107  *     http://java.sun.com/index.html
 108  * </pre></blockquote>
 109  * contained within it the relative URL:
 110  * <blockquote><pre>
 111  *     FAQ.html
 112  * </pre></blockquote>
 113  * it would be a shorthand for:
 114  * <blockquote><pre>
 115  *     http://java.sun.com/FAQ.html
 116  * </pre></blockquote>
 117  * <p>
 118  * The relative URL need not specify all the components of a URL. If
 119  * the protocol, host name, or port number is missing, the value is
 120  * inherited from the fully specified URL. The file component must be
 121  * specified. The optional fragment is not inherited.
 122  * <p>
 123  * The URL class does not itself encode or decode any URL components
 124  * according to the escaping mechanism defined in RFC2396. It is the
 125  * responsibility of the caller to encode any fields, which need to be
 126  * escaped prior to calling URL, and also to decode any escaped fields,
 127  * that are returned from URL. Furthermore, because URL has no knowledge
 128  * of URL escaping, it does not recognise equivalence between the encoded
 129  * or decoded form of the same URL. For example, the two URLs:<br>
 130  * <pre>    http://foo.com/hello world/ and http://foo.com/hello%20world</pre>
 131  * would be considered not equal to each other.
 132  * <p>
 133  * Note, the {@link java.net.URI} class does perform escaping of its
 134  * component fields in certain circumstances. The recommended way
 135  * to manage the encoding and decoding of URLs is to use {@link java.net.URI},
 136  * and to convert between these two classes using {@link #toURI()} and
 137  * {@link URI#toURL()}.
 138  * <p>
 139  * The {@link URLEncoder} and {@link URLDecoder} classes can also be
 140  * used, but only for HTML form encoding, which is not the same
 141  * as the encoding scheme defined in RFC2396.
 142  *
 143  * @author  James Gosling
 144  * @since 1.0
 145  */
 146 public final class URL implements java.io.Serializable {
 147 
 148     static final long serialVersionUID = -7627629688361524110L;
 149 
 150     /**
 151      * The property which specifies the package prefix list to be scanned
 152      * for protocol handlers.  The value of this property (if any) should
 153      * be a vertical bar delimited list of package names to search through
 154      * for a protocol handler to load.  The policy of this class is that
 155      * all protocol handlers will be in a class called <protocolname>.Handler,
 156      * and each package in the list is examined in turn for a matching
 157      * handler.  If none are found (or the property is not specified), the
 158      * default package prefix, sun.net.www.protocol, is used.  The search
 159      * proceeds from the first package in the list to the last and stops
 160      * when a match is found.
 161      */
 162     private static final String protocolPathProp = "java.protocol.handler.pkgs";
 163 
 164     /**
 165      * The protocol to use (ftp, http, nntp, ... etc.) .
 166      * @serial
 167      */
 168     private String protocol;
 169 
 170     /**
 171      * The host name to connect to.
 172      * @serial
 173      */
 174     private String host;
 175 
 176     /**
 177      * The protocol port to connect to.
 178      * @serial
 179      */
 180     private int port = -1;
 181 
 182     /**
 183      * The specified file name on that host. {@code file} is
 184      * defined as {@code path[?query]}
 185      * @serial
 186      */
 187     private String file;
 188 
 189     /**
 190      * The query part of this URL.
 191      */
 192     private transient String query;
 193 
 194     /**
 195      * The authority part of this URL.
 196      * @serial
 197      */
 198     private String authority;
 199 
 200     /**
 201      * The path part of this URL.
 202      */
 203     private transient String path;
 204 
 205     /**
 206      * The userinfo part of this URL.
 207      */
 208     private transient String userInfo;
 209 
 210     /**
 211      * # reference.
 212      * @serial
 213      */
 214     private String ref;
 215 
 216     /**
 217      * The host's IP address, used in equals and hashCode.
 218      * Computed on demand. An uninitialized or unknown hostAddress is null.
 219      */
 220     transient InetAddress hostAddress;
 221 
 222     /**
 223      * The URLStreamHandler for this URL.
 224      */
 225     transient URLStreamHandler handler;
 226 
 227     /* Our hash code.
 228      * @serial
 229      */
 230     private int hashCode = -1;
 231 
 232     /**
 233      * Creates a {@code URL} object from the specified
 234      * {@code protocol}, {@code host}, {@code port}
 235      * number, and {@code file}.<p>
 236      *
 237      * {@code host} can be expressed as a host name or a literal
 238      * IP address. If IPv6 literal address is used, it should be
 239      * enclosed in square brackets ({@code '['} and {@code ']'}), as
 240      * specified by <a
 241      * href="http://www.ietf.org/rfc/rfc2732.txt">RFC&nbsp;2732</a>;
 242      * However, the literal IPv6 address format defined in <a
 243      * href="http://www.ietf.org/rfc/rfc2373.txt"><i>RFC&nbsp;2373: IP
 244      * Version 6 Addressing Architecture</i></a> is also accepted.<p>
 245      *
 246      * Specifying a {@code port} number of {@code -1}
 247      * indicates that the URL should use the default port for the
 248      * protocol.<p>
 249      *
 250      * If this is the first URL object being created with the specified
 251      * protocol, a <i>stream protocol handler</i> object, an instance of
 252      * class {@code URLStreamHandler}, is created for that protocol:
 253      * <ol>
 254      * <li>If the application has previously set up an instance of
 255      *     {@code URLStreamHandlerFactory}, through {@linkplain
 256      *     #setURLStreamHandlerFactory(URLStreamHandlerFactory)
 257      *     setURLStreamHandlerFactory}, as the stream handler factory,
 258      *     then the {@code createURLStreamHandler} method of that instance
 259      *     is called with the protocol string as an argument to create the
 260      *     stream protocol handler.
 261      * <li>If no {@code URLStreamHandlerFactory} has yet been set up,
 262      *     or if the factory's {@code createURLStreamHandler} method
 263      *     returns {@code null}, then the list of factories, set through
 264      *     {@linkplain #addURLStreamHandlerFactory(URLStreamHandlerFactory)
 265      *     addURLStreamHandlerFactory} is consulted. The {@code
 266      *     createURLStreamHandler} method of each factory is invoked, in
 267      *     registration order, with the protocol string, until a factory returns
 268      *     non-null, or all the factories in the list have been exhausted.
 269      * <li>If the previous step fails to find a protocol handler, then the
 270      *     {@linkplain java.util.ServiceLoader ServiceLoader} mechanism is used
 271      *     to locate a {@code URLStreamHandlerFactory} provider using the system
 272      *     class loader. The ordering that providers are located is
 273      *     implementation specific, and an implementation is free to cache the
 274      *     located providers. A {@linkplain java.util.ServiceConfigurationError
 275      *     ServiceConfigurationError}, {@code Error} or {@code RuntimeException}
 276      *     thrown from the {@code createURLStreamHandler}, if encountered, will
 277      *     be propagated to the calling thread. The {@code
 278      *     createURLStreamHandler} method of each provider, if instantiated, is
 279      *     invoked, with the protocol string, until a provider returns non-null,
 280      *     or all providers have been exhausted.
 281      * <li>If the previous step fails to find a protocol handler, then the
 282      *     constructor tries to load a built-in protocol handler.
 283      *     If this class does not exist, or if the class exists but it is not a
 284      *     subclass of {@code URLStreamHandler}, then a
 285      *     {@code MalformedURLException} is thrown.
 286      * </ol>
 287      *
 288      * <p>Protocol handlers for the following protocols are guaranteed
 289      * to exist on the search path :-
 290      * <blockquote><pre>
 291      *     http, https, file, and jar
 292      * </pre></blockquote>
 293      * Protocol handlers for additional protocols may also be  available. Some
 294      * protocols, that are fundamental to the platform, may have restrictions
 295      * around when, or if, their built-in handlers can be overridden.
 296      *
 297      * <p>No validation of the inputs is performed by this constructor.
 298      *
 299      * @param      protocol   the name of the protocol to use.
 300      * @param      host       the name of the host.
 301      * @param      port       the port number on the host.
 302      * @param      file       the file on the host
 303      * @exception  MalformedURLException  if an unknown protocol is specified.
 304      * @see        java.lang.System#getProperty(java.lang.String)
 305      * @see        java.net.URL#setURLStreamHandlerFactory(
 306      *                  java.net.URLStreamHandlerFactory)
 307      * @see        java.net.URLStreamHandler
 308      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 309      *                  java.lang.String)
 310      */
 311     public URL(String protocol, String host, int port, String file)
 312         throws MalformedURLException
 313     {
 314         this(protocol, host, port, file, null);
 315     }
 316 
 317     /**
 318      * Creates a URL from the specified {@code protocol}
 319      * name, {@code host} name, and {@code file} name. The
 320      * default port for the specified protocol is used.
 321      * <p>
 322      * This method is equivalent to calling the four-argument
 323      * constructor with the arguments being {@code protocol},
 324      * {@code host}, {@code -1}, and {@code file}.
 325      *
 326      * No validation of the inputs is performed by this constructor.
 327      *
 328      * @param      protocol   the name of the protocol to use.
 329      * @param      host       the name of the host.
 330      * @param      file       the file on the host.
 331      * @exception  MalformedURLException  if an unknown protocol is specified.
 332      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 333      *                  int, java.lang.String)
 334      */
 335     public URL(String protocol, String host, String file)
 336             throws MalformedURLException {
 337         this(protocol, host, -1, file);
 338     }
 339 
 340     /**
 341      * Creates a {@code URL} object from the specified
 342      * {@code protocol}, {@code host}, {@code port}
 343      * number, {@code file}, and {@code handler}. Specifying
 344      * a {@code port} number of {@code -1} indicates that
 345      * the URL should use the default port for the protocol. Specifying
 346      * a {@code handler} of {@code null} indicates that the URL
 347      * should use a default stream handler for the protocol, as outlined
 348      * for:
 349      *     java.net.URL#URL(java.lang.String, java.lang.String, int,
 350      *                      java.lang.String)
 351      *
 352      * <p>If the handler is not null and there is a security manager,
 353      * the security manager's {@code checkPermission}
 354      * method is called with a
 355      * {@code NetPermission("specifyStreamHandler")} permission.
 356      * This may result in a SecurityException.
 357      *
 358      * No validation of the inputs is performed by this constructor.
 359      *
 360      * @param      protocol   the name of the protocol to use.
 361      * @param      host       the name of the host.
 362      * @param      port       the port number on the host.
 363      * @param      file       the file on the host
 364      * @param      handler    the stream handler for the URL.
 365      * @exception  MalformedURLException  if an unknown protocol is specified.
 366      * @exception  SecurityException
 367      *        if a security manager exists and its
 368      *        {@code checkPermission} method doesn't allow
 369      *        specifying a stream handler explicitly.
 370      * @see        java.lang.System#getProperty(java.lang.String)
 371      * @see        java.net.URL#setURLStreamHandlerFactory(
 372      *                  java.net.URLStreamHandlerFactory)
 373      * @see        java.net.URLStreamHandler
 374      * @see        java.net.URLStreamHandlerFactory#createURLStreamHandler(
 375      *                  java.lang.String)
 376      * @see        SecurityManager#checkPermission
 377      * @see        java.net.NetPermission
 378      */
 379     public URL(String protocol, String host, int port, String file,
 380                URLStreamHandler handler) throws MalformedURLException {
 381         if (handler != null) {
 382             SecurityManager sm = System.getSecurityManager();
 383             if (sm != null) {
 384                 // check for permission to specify a handler
 385                 checkSpecifyHandler(sm);
 386             }
 387         }
 388 
 389         protocol = protocol.toLowerCase();
 390         this.protocol = protocol;
 391         if (host != null) {
 392 
 393             /**
 394              * if host is a literal IPv6 address,
 395              * we will make it conform to RFC 2732
 396              */
 397             if (host.indexOf(':') >= 0 && !host.startsWith("[")) {
 398                 host = "["+host+"]";
 399             }
 400             this.host = host;
 401 
 402             if (port < -1) {
 403                 throw new MalformedURLException("Invalid port number :" +
 404                                                     port);
 405             }
 406             this.port = port;
 407             authority = (port == -1) ? host : host + ":" + port;
 408         }
 409 
 410         Parts parts = new Parts(file);
 411         path = parts.getPath();
 412         query = parts.getQuery();
 413 
 414         if (query != null) {
 415             this.file = path + "?" + query;
 416         } else {
 417             this.file = path;
 418         }
 419         ref = parts.getRef();
 420 
 421         // Note: we don't do validation of the URL here. Too risky to change
 422         // right now, but worth considering for future reference. -br
 423         if (handler == null &&
 424             (handler = getURLStreamHandler(protocol)) == null) {
 425             throw new MalformedURLException("unknown protocol: " + protocol);
 426         }
 427         this.handler = handler;
 428     }
 429 
 430     /**
 431      * Creates a {@code URL} object from the {@code String}
 432      * representation.
 433      * <p>
 434      * This constructor is equivalent to a call to the two-argument
 435      * constructor with a {@code null} first argument.
 436      *
 437      * @param      spec   the {@code String} to parse as a URL.
 438      * @exception  MalformedURLException  if no protocol is specified, or an
 439      *               unknown protocol is found, or {@code spec} is {@code null}.
 440      * @see        java.net.URL#URL(java.net.URL, java.lang.String)
 441      */
 442     public URL(String spec) throws MalformedURLException {
 443         this(null, spec);
 444     }
 445 
 446     /**
 447      * Creates a URL by parsing the given spec within a specified context.
 448      *
 449      * The new URL is created from the given context URL and the spec
 450      * argument as described in
 451      * RFC2396 &quot;Uniform Resource Identifiers : Generic * Syntax&quot; :
 452      * <blockquote><pre>
 453      *          &lt;scheme&gt;://&lt;authority&gt;&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;
 454      * </pre></blockquote>
 455      * The reference is parsed into the scheme, authority, path, query and
 456      * fragment parts. If the path component is empty and the scheme,
 457      * authority, and query components are undefined, then the new URL is a
 458      * reference to the current document. Otherwise, the fragment and query
 459      * parts present in the spec are used in the new URL.
 460      * <p>
 461      * If the scheme component is defined in the given spec and does not match
 462      * the scheme of the context, then the new URL is created as an absolute
 463      * URL based on the spec alone. Otherwise the scheme component is inherited
 464      * from the context URL.
 465      * <p>
 466      * If the authority component is present in the spec then the spec is
 467      * treated as absolute and the spec authority and path will replace the
 468      * context authority and path. If the authority component is absent in the
 469      * spec then the authority of the new URL will be inherited from the
 470      * context.
 471      * <p>
 472      * If the spec's path component begins with a slash character
 473      * &quot;/&quot; then the
 474      * path is treated as absolute and the spec path replaces the context path.
 475      * <p>
 476      * Otherwise, the path is treated as a relative path and is appended to the
 477      * context path, as described in RFC2396. Also, in this case,
 478      * the path is canonicalized through the removal of directory
 479      * changes made by occurrences of &quot;..&quot; and &quot;.&quot;.
 480      * <p>
 481      * For a more detailed description of URL parsing, refer to RFC2396.
 482      *
 483      * @param      context   the context in which to parse the specification.
 484      * @param      spec      the {@code String} to parse as a URL.
 485      * @exception  MalformedURLException  if no protocol is specified, or an
 486      *               unknown protocol is found, or {@code spec} is {@code null}.
 487      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 488      *                  int, java.lang.String)
 489      * @see        java.net.URLStreamHandler
 490      * @see        java.net.URLStreamHandler#parseURL(java.net.URL,
 491      *                  java.lang.String, int, int)
 492      */
 493     public URL(URL context, String spec) throws MalformedURLException {
 494         this(context, spec, null);
 495     }
 496 
 497     /**
 498      * Creates a URL by parsing the given spec with the specified handler
 499      * within a specified context. If the handler is null, the parsing
 500      * occurs as with the two argument constructor.
 501      *
 502      * @param      context   the context in which to parse the specification.
 503      * @param      spec      the {@code String} to parse as a URL.
 504      * @param      handler   the stream handler for the URL.
 505      * @exception  MalformedURLException  if no protocol is specified, or an
 506      *               unknown protocol is found, or {@code spec} is {@code null}.
 507      * @exception  SecurityException
 508      *        if a security manager exists and its
 509      *        {@code checkPermission} method doesn't allow
 510      *        specifying a stream handler.
 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, URLStreamHandler handler)
 518         throws MalformedURLException
 519     {
 520         String original = spec;
 521         int i, limit, c;
 522         int start = 0;
 523         String newProtocol = null;
 524         boolean aRef=false;
 525         boolean isRelative = false;
 526 
 527         // Check for permission to specify a handler
 528         if (handler != null) {
 529             SecurityManager sm = System.getSecurityManager();
 530             if (sm != null) {
 531                 checkSpecifyHandler(sm);
 532             }
 533         }
 534 
 535         try {
 536             limit = spec.length();
 537             while ((limit > 0) && (spec.charAt(limit - 1) <= ' ')) {
 538                 limit--;        //eliminate trailing whitespace
 539             }
 540             while ((start < limit) && (spec.charAt(start) <= ' ')) {
 541                 start++;        // eliminate leading whitespace
 542             }
 543 
 544             if (spec.regionMatches(true, start, "url:", 0, 4)) {
 545                 start += 4;
 546             }
 547             if (start < spec.length() && spec.charAt(start) == '#') {
 548                 /* we're assuming this is a ref relative to the context URL.
 549                  * This means protocols cannot start w/ '#', but we must parse
 550                  * ref URL's like: "hello:there" w/ a ':' in them.
 551                  */
 552                 aRef=true;
 553             }
 554             for (i = start ; !aRef && (i < limit) &&
 555                      ((c = spec.charAt(i)) != '/') ; i++) {
 556                 if (c == ':') {
 557 
 558                     String s = spec.substring(start, i).toLowerCase();
 559                     if (isValidProtocol(s)) {
 560                         newProtocol = s;
 561                         start = i + 1;
 562                     }
 563                     break;
 564                 }
 565             }
 566 
 567             // Only use our context if the protocols match.
 568             protocol = newProtocol;
 569             if ((context != null) && ((newProtocol == null) ||
 570                             newProtocol.equalsIgnoreCase(context.protocol))) {
 571                 // inherit the protocol handler from the context
 572                 // if not specified to the constructor
 573                 if (handler == null) {
 574                     handler = context.handler;
 575                 }
 576 
 577                 // If the context is a hierarchical URL scheme and the spec
 578                 // contains a matching scheme then maintain backwards
 579                 // compatibility and treat it as if the spec didn't contain
 580                 // the scheme; see 5.2.3 of RFC2396
 581                 if (context.path != null && context.path.startsWith("/"))
 582                     newProtocol = null;
 583 
 584                 if (newProtocol == null) {
 585                     protocol = context.protocol;
 586                     authority = context.authority;
 587                     userInfo = context.userInfo;
 588                     host = context.host;
 589                     port = context.port;
 590                     file = context.file;
 591                     path = context.path;
 592                     isRelative = true;
 593                 }
 594             }
 595 
 596             if (protocol == null) {
 597                 throw new MalformedURLException("no protocol: "+original);
 598             }
 599 
 600             // Get the protocol handler if not specified or the protocol
 601             // of the context could not be used
 602             if (handler == null &&
 603                 (handler = getURLStreamHandler(protocol)) == null) {
 604                 throw new MalformedURLException("unknown protocol: "+protocol);
 605             }
 606 
 607             this.handler = handler;
 608 
 609             i = spec.indexOf('#', start);
 610             if (i >= 0) {
 611                 ref = spec.substring(i + 1, limit);
 612                 limit = i;
 613             }
 614 
 615             /*
 616              * Handle special case inheritance of query and fragment
 617              * implied by RFC2396 section 5.2.2.
 618              */
 619             if (isRelative && start == limit) {
 620                 query = context.query;
 621                 if (ref == null) {
 622                     ref = context.ref;
 623                 }
 624             }
 625 
 626             handler.parseURL(this, spec, start, limit);
 627 
 628         } catch(MalformedURLException e) {
 629             throw e;
 630         } catch(Exception e) {
 631             MalformedURLException exception = new MalformedURLException(e.getMessage());
 632             exception.initCause(e);
 633             throw exception;
 634         }
 635     }
 636 
 637     /*
 638      * Returns true if specified string is a valid protocol name.
 639      */
 640     private boolean isValidProtocol(String protocol) {
 641         int len = protocol.length();
 642         if (len < 1)
 643             return false;
 644         char c = protocol.charAt(0);
 645         if (!Character.isLetter(c))
 646             return false;
 647         for (int i = 1; i < len; i++) {
 648             c = protocol.charAt(i);
 649             if (!Character.isLetterOrDigit(c) && c != '.' && c != '+' &&
 650                 c != '-') {
 651                 return false;
 652             }
 653         }
 654         return true;
 655     }
 656 
 657     /*
 658      * Checks for permission to specify a stream handler.
 659      */
 660     private void checkSpecifyHandler(SecurityManager sm) {
 661         sm.checkPermission(SecurityConstants.SPECIFY_HANDLER_PERMISSION);
 662     }
 663 
 664     /**
 665      * Sets the fields of the URL. This is not a public method so that
 666      * only URLStreamHandlers can modify URL fields. URLs are
 667      * otherwise constant.
 668      *
 669      * @param protocol the name of the protocol to use
 670      * @param host the name of the host
 671        @param port the port number on the host
 672      * @param file the file on the host
 673      * @param ref the internal reference in the URL
 674      */
 675     void set(String protocol, String host, int port,
 676              String file, String ref) {
 677         synchronized (this) {
 678             this.protocol = protocol;
 679             this.host = host;
 680             authority = port == -1 ? host : host + ":" + port;
 681             this.port = port;
 682             this.file = file;
 683             this.ref = ref;
 684             /* This is very important. We must recompute this after the
 685              * URL has been changed. */
 686             hashCode = -1;
 687             hostAddress = null;
 688             int q = file.lastIndexOf('?');
 689             if (q != -1) {
 690                 query = file.substring(q+1);
 691                 path = file.substring(0, q);
 692             } else
 693                 path = file;
 694         }
 695     }
 696 
 697     /**
 698      * Sets the specified 8 fields of the URL. This is not a public method so
 699      * that only URLStreamHandlers can modify URL fields. URLs are otherwise
 700      * constant.
 701      *
 702      * @param protocol the name of the protocol to use
 703      * @param host the name of the host
 704      * @param port the port number on the host
 705      * @param authority the authority part for the url
 706      * @param userInfo the username and password
 707      * @param path the file on the host
 708      * @param ref the internal reference in the URL
 709      * @param query the query part of this URL
 710      * @since 1.3
 711      */
 712     void set(String protocol, String host, int port,
 713              String authority, String userInfo, String path,
 714              String query, String ref) {
 715         synchronized (this) {
 716             this.protocol = protocol;
 717             this.host = host;
 718             this.port = port;
 719             this.file = query == null ? path : path + "?" + query;
 720             this.userInfo = userInfo;
 721             this.path = path;
 722             this.ref = ref;
 723             /* This is very important. We must recompute this after the
 724              * URL has been changed. */
 725             hashCode = -1;
 726             hostAddress = null;
 727             this.query = query;
 728             this.authority = authority;
 729         }
 730     }
 731 
 732     /**
 733      * Gets the query part of this {@code URL}.
 734      *
 735      * @return  the query part of this {@code URL},
 736      * or <CODE>null</CODE> if one does not exist
 737      * @since 1.3
 738      */
 739     public String getQuery() {
 740         return query;
 741     }
 742 
 743     /**
 744      * Gets the path part of this {@code URL}.
 745      *
 746      * @return  the path part of this {@code URL}, or an
 747      * empty string if one does not exist
 748      * @since 1.3
 749      */
 750     public String getPath() {
 751         return path;
 752     }
 753 
 754     /**
 755      * Gets the userInfo part of this {@code URL}.
 756      *
 757      * @return  the userInfo part of this {@code URL}, or
 758      * <CODE>null</CODE> if one does not exist
 759      * @since 1.3
 760      */
 761     public String getUserInfo() {
 762         return userInfo;
 763     }
 764 
 765     /**
 766      * Gets the authority part of this {@code URL}.
 767      *
 768      * @return  the authority part of this {@code URL}
 769      * @since 1.3
 770      */
 771     public String getAuthority() {
 772         return authority;
 773     }
 774 
 775     /**
 776      * Gets the port number of this {@code URL}.
 777      *
 778      * @return  the port number, or -1 if the port is not set
 779      */
 780     public int getPort() {
 781         return port;
 782     }
 783 
 784     /**
 785      * Gets the default port number of the protocol associated
 786      * with this {@code URL}. If the URL scheme or the URLStreamHandler
 787      * for the URL do not define a default port number,
 788      * then -1 is returned.
 789      *
 790      * @return  the port number
 791      * @since 1.4
 792      */
 793     public int getDefaultPort() {
 794         return handler.getDefaultPort();
 795     }
 796 
 797     /**
 798      * Gets the protocol name of this {@code URL}.
 799      *
 800      * @return  the protocol of this {@code URL}.
 801      */
 802     public String getProtocol() {
 803         return protocol;
 804     }
 805 
 806     /**
 807      * Gets the host name of this {@code URL}, if applicable.
 808      * The format of the host conforms to RFC 2732, i.e. for a
 809      * literal IPv6 address, this method will return the IPv6 address
 810      * enclosed in square brackets ({@code '['} and {@code ']'}).
 811      *
 812      * @return  the host name of this {@code URL}.
 813      */
 814     public String getHost() {
 815         return host;
 816     }
 817 
 818     /**
 819      * Gets the file name of this {@code URL}.
 820      * The returned file portion will be
 821      * the same as <CODE>getPath()</CODE>, plus the concatenation of
 822      * the value of <CODE>getQuery()</CODE>, if any. If there is
 823      * no query portion, this method and <CODE>getPath()</CODE> will
 824      * return identical results.
 825      *
 826      * @return  the file name of this {@code URL},
 827      * or an empty string if one does not exist
 828      */
 829     public String getFile() {
 830         return file;
 831     }
 832 
 833     /**
 834      * Gets the anchor (also known as the "reference") of this
 835      * {@code URL}.
 836      *
 837      * @return  the anchor (also known as the "reference") of this
 838      *          {@code URL}, or <CODE>null</CODE> if one does not exist
 839      */
 840     public String getRef() {
 841         return ref;
 842     }
 843 
 844     /**
 845      * Compares this URL for equality with another object.<p>
 846      *
 847      * If the given object is not a URL then this method immediately returns
 848      * {@code false}.<p>
 849      *
 850      * Two URL objects are equal if they have the same protocol, reference
 851      * equivalent hosts, have the same port number on the host, and the same
 852      * file and fragment of the file.<p>
 853      *
 854      * Two hosts are considered equivalent if both host names can be resolved
 855      * into the same IP addresses; else if either host name can't be
 856      * resolved, the host names must be equal without regard to case; or both
 857      * host names equal to null.<p>
 858      *
 859      * Since hosts comparison requires name resolution, this operation is a
 860      * blocking operation. <p>
 861      *
 862      * Note: The defined behavior for {@code equals} is known to
 863      * be inconsistent with virtual hosting in HTTP.
 864      *
 865      * @param   obj   the URL to compare against.
 866      * @return  {@code true} if the objects are the same;
 867      *          {@code false} otherwise.
 868      */
 869     public boolean equals(Object obj) {
 870         if (!(obj instanceof URL))
 871             return false;
 872         URL u2 = (URL)obj;
 873 
 874         return handler.equals(this, u2);
 875     }
 876 
 877     /**
 878      * Creates an integer suitable for hash table indexing.<p>
 879      *
 880      * The hash code is based upon all the URL components relevant for URL
 881      * comparison. As such, this operation is a blocking operation.
 882      *
 883      * @return  a hash code for this {@code URL}.
 884      */
 885     public synchronized int hashCode() {
 886         if (hashCode != -1)
 887             return hashCode;
 888 
 889         hashCode = handler.hashCode(this);
 890         return hashCode;
 891     }
 892 
 893     /**
 894      * Compares two URLs, excluding the fragment component.<p>
 895      *
 896      * Returns {@code true} if this {@code URL} and the
 897      * {@code other} argument are equal without taking the
 898      * fragment component into consideration.
 899      *
 900      * @param   other   the {@code URL} to compare against.
 901      * @return  {@code true} if they reference the same remote object;
 902      *          {@code false} otherwise.
 903      */
 904     public boolean sameFile(URL other) {
 905         return handler.sameFile(this, other);
 906     }
 907 
 908     /**
 909      * Constructs a string representation of this {@code URL}. The
 910      * string is created by calling the {@code toExternalForm}
 911      * method of the stream protocol handler for this object.
 912      *
 913      * @return  a string representation of this object.
 914      * @see     java.net.URL#URL(java.lang.String, java.lang.String, int,
 915      *                  java.lang.String)
 916      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 917      */
 918     public String toString() {
 919         return toExternalForm();
 920     }
 921 
 922     /**
 923      * Constructs a string representation of this {@code URL}. The
 924      * string is created by calling the {@code toExternalForm}
 925      * method of the stream protocol handler for this object.
 926      *
 927      * @return  a string representation of this object.
 928      * @see     java.net.URL#URL(java.lang.String, java.lang.String,
 929      *                  int, java.lang.String)
 930      * @see     java.net.URLStreamHandler#toExternalForm(java.net.URL)
 931      */
 932     public String toExternalForm() {
 933         return handler.toExternalForm(this);
 934     }
 935 
 936     /**
 937      * Returns a {@link java.net.URI} equivalent to this URL.
 938      * This method functions in the same way as {@code new URI (this.toString())}.
 939      * <p>Note, any URL instance that complies with RFC 2396 can be converted
 940      * to a URI. However, some URLs that are not strictly in compliance
 941      * can not be converted to a URI.
 942      *
 943      * @exception URISyntaxException if this URL is not formatted strictly according to
 944      *            to RFC2396 and cannot be converted to a URI.
 945      *
 946      * @return    a URI instance equivalent to this URL.
 947      * @since 1.5
 948      */
 949     public URI toURI() throws URISyntaxException {
 950         return new URI (toString());
 951     }
 952 
 953     /**
 954      * Returns a {@link java.net.URLConnection URLConnection} instance that
 955      * represents a connection to the remote object referred to by the
 956      * {@code URL}.
 957      *
 958      * <P>A new instance of {@linkplain java.net.URLConnection URLConnection} is
 959      * created every time when invoking the
 960      * {@linkplain java.net.URLStreamHandler#openConnection(URL)
 961      * URLStreamHandler.openConnection(URL)} method of the protocol handler for
 962      * this URL.</P>
 963      *
 964      * <P>It should be noted that a URLConnection instance does not establish
 965      * the actual network connection on creation. This will happen only when
 966      * calling {@linkplain java.net.URLConnection#connect() URLConnection.connect()}.</P>
 967      *
 968      * <P>If for the URL's protocol (such as HTTP or JAR), there
 969      * exists a public, specialized URLConnection subclass belonging
 970      * to one of the following packages or one of their subpackages:
 971      * java.lang, java.io, java.util, java.net, the connection
 972      * returned will be of that subclass. For example, for HTTP an
 973      * HttpURLConnection will be returned, and for JAR a
 974      * JarURLConnection will be returned.</P>
 975      *
 976      * @return     a {@link java.net.URLConnection URLConnection} linking
 977      *             to the URL.
 978      * @exception  IOException  if an I/O exception occurs.
 979      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
 980      *             int, java.lang.String)
 981      */
 982     public URLConnection openConnection() throws java.io.IOException {
 983         return handler.openConnection(this);
 984     }
 985 
 986     /**
 987      * Same as {@link #openConnection()}, except that the connection will be
 988      * made through the specified proxy; Protocol handlers that do not
 989      * support proxing will ignore the proxy parameter and make a
 990      * normal connection.
 991      *
 992      * Invoking this method preempts the system's default
 993      * {@link java.net.ProxySelector ProxySelector} settings.
 994      *
 995      * @param      proxy the Proxy through which this connection
 996      *             will be made. If direct connection is desired,
 997      *             Proxy.NO_PROXY should be specified.
 998      * @return     a {@code URLConnection} to the URL.
 999      * @exception  IOException  if an I/O exception occurs.
1000      * @exception  SecurityException if a security manager is present
1001      *             and the caller doesn't have permission to connect
1002      *             to the proxy.
1003      * @exception  IllegalArgumentException will be thrown if proxy is null,
1004      *             or proxy has the wrong type
1005      * @exception  UnsupportedOperationException if the subclass that
1006      *             implements the protocol handler doesn't support
1007      *             this method.
1008      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1009      *             int, java.lang.String)
1010      * @see        java.net.URLConnection
1011      * @see        java.net.URLStreamHandler#openConnection(java.net.URL,
1012      *             java.net.Proxy)
1013      * @since      1.5
1014      */
1015     public URLConnection openConnection(Proxy proxy)
1016         throws java.io.IOException {
1017         if (proxy == null) {
1018             throw new IllegalArgumentException("proxy can not be null");
1019         }
1020 
1021         // Create a copy of Proxy as a security measure
1022         Proxy p = proxy == Proxy.NO_PROXY ? Proxy.NO_PROXY : sun.net.ApplicationProxy.create(proxy);
1023         SecurityManager sm = System.getSecurityManager();
1024         if (p.type() != Proxy.Type.DIRECT && sm != null) {
1025             InetSocketAddress epoint = (InetSocketAddress) p.address();
1026             if (epoint.isUnresolved())
1027                 sm.checkConnect(epoint.getHostName(), epoint.getPort());
1028             else
1029                 sm.checkConnect(epoint.getAddress().getHostAddress(),
1030                                 epoint.getPort());
1031         }
1032         return handler.openConnection(this, p);
1033     }
1034 
1035     /**
1036      * Opens a connection to this {@code URL} and returns an
1037      * {@code InputStream} for reading from that connection. This
1038      * method is a shorthand for:
1039      * <blockquote><pre>
1040      *     openConnection().getInputStream()
1041      * </pre></blockquote>
1042      *
1043      * @return     an input stream for reading from the URL connection.
1044      * @exception  IOException  if an I/O exception occurs.
1045      * @see        java.net.URL#openConnection()
1046      * @see        java.net.URLConnection#getInputStream()
1047      */
1048     public final InputStream openStream() throws java.io.IOException {
1049         return openConnection().getInputStream();
1050     }
1051 
1052     /**
1053      * Gets the contents of this URL. This method is a shorthand for:
1054      * <blockquote><pre>
1055      *     openConnection().getContent()
1056      * </pre></blockquote>
1057      *
1058      * @return     the contents of this URL.
1059      * @exception  IOException  if an I/O exception occurs.
1060      * @see        java.net.URLConnection#getContent()
1061      */
1062     public final Object getContent() throws java.io.IOException {
1063         return openConnection().getContent();
1064     }
1065 
1066     /**
1067      * Gets the contents of this URL. This method is a shorthand for:
1068      * <blockquote><pre>
1069      *     openConnection().getContent(classes)
1070      * </pre></blockquote>
1071      *
1072      * @param classes an array of Java types
1073      * @return     the content object of this URL that is the first match of
1074      *               the types specified in the classes array.
1075      *               null if none of the requested types are supported.
1076      * @exception  IOException  if an I/O exception occurs.
1077      * @see        java.net.URLConnection#getContent(Class[])
1078      * @since 1.3
1079      */
1080     public final Object getContent(Class<?>[] classes)
1081     throws java.io.IOException {
1082         return openConnection().getContent(classes);
1083     }
1084 
1085     /**
1086      * The Application URLStreamHandler factory.
1087      */
1088     private static volatile URLStreamHandlerFactory factory;
1089 
1090     /** The list of factories. */
1091     private static final CopyOnWriteArrayList<URLStreamHandlerFactory> factoryList =
1092             new CopyOnWriteArrayList<>();
1093 
1094     /**
1095      * Sets an application's {@code URLStreamHandlerFactory}.
1096      * This method can be called at most once in a given Java Virtual
1097      * Machine.
1098      *
1099      *<p> The {@code URLStreamHandlerFactory} instance is used to
1100      *construct a stream protocol handler from a protocol name.
1101      *
1102      * <p> If there is a security manager, this method first calls
1103      * the security manager's {@code checkSetFactory} method
1104      * to ensure the operation is allowed.
1105      * This could result in a SecurityException.
1106      *
1107      * @param      fac   the desired factory.
1108      * @exception  Error  if the application has already set a factory.
1109      * @exception  SecurityException  if a security manager exists and its
1110      *             {@code checkSetFactory} method doesn't allow
1111      *             the operation.
1112      * @see        java.net.URL#URL(java.lang.String, java.lang.String,
1113      *             int, java.lang.String)
1114      * @see        java.net.URLStreamHandlerFactory
1115      * @see        SecurityManager#checkSetFactory
1116      */
1117     public static void setURLStreamHandlerFactory(URLStreamHandlerFactory fac) {
1118         synchronized (streamHandlerLock) {
1119             if (factory != null) {
1120                 throw new Error("factory already defined");
1121             }
1122             SecurityManager security = System.getSecurityManager();
1123             if (security != null) {
1124                 security.checkSetFactory();
1125             }
1126             handlers.clear();
1127 




1128             // safe publication of URLStreamHandlerFactory with volatile write
1129             factory = fac;
1130         }
1131     }
1132 
1133     /**
1134      * Adds a {@linkplain URLStreamHandlerFactory}. This method can be called
1135      * multiple times in order to create an effective list of factories.
1136      *
1137      * <p> Factories, added through a call to this method, will have their
1138      * {@code createURLStreamHandler} method called, in the order in which they
1139      * were added, to construct a stream protocol handler from a protocol name.
1140      * A factory that cannot construct a stream protocol handler for a
1141      * particular protocol name should return {@code null}. The next factory in
1142      * the list, if there is one, will then be consulted.
1143      *
1144      * <p> If there is a security manager, this method first calls
1145      * the security manager's {@code checkSetFactory} method
1146      * to ensure the operation is allowed.
1147      * This could result in a SecurityException.
1148      *
1149      * @apiNote
1150      * This method is intended to be used by long running applications, to
1151      * support adding additional system-wide protocol handlers, beyond that of
1152      * the built-in handlers. It can be used in some situations to override
1153      * built-in handlers, that may not be possible to locate using services,
1154      * like {@code jar} for example.
1155      *
1156      * @param  factory the factory
1157      * @throws SecurityException  if a security manager exists and its {@link
1158      *         SecurityManager#checkSetFactory} method doesn't allow the operation
1159      * @throws NullPointerException if {@code factory} is null
1160      * @since 1.9
1161      */
1162     public static void addURLStreamHandlerFactory(URLStreamHandlerFactory factory) {
1163         Objects.requireNonNull(factory);
1164         synchronized (streamHandlerLock) {
1165             SecurityManager security = System.getSecurityManager();
1166             if (security != null) {
1167                 security.checkSetFactory();
1168             }
1169             handlers.clear();
1170 
1171             factoryList.add(factory);
1172         }
1173     }


1174 
1175     private static final URLStreamHandlerFactory defaultFactory = new DefaultFactory();

1176 
1177     private static class DefaultFactory implements URLStreamHandlerFactory {
1178         private static String PREFIX = "sun.net.www.protocol";
1179 
1180         public URLStreamHandler createURLStreamHandler(String protocol) {
1181             String name = PREFIX + "." + protocol + ".Handler";
1182             try {
1183                 Class<?> c = Class.forName(name);
1184                 return (URLStreamHandler)c.newInstance();
1185             } catch (ClassNotFoundException x) {
1186                 // ignore
1187             } catch (Exception e) {
1188                 // For compatibility, all Exceptions are ignored.
1189                 // any number of exceptions can get thrown here
1190             }
1191             return null;
1192         }
1193     }
1194 
1195     private static final URLStreamHandler NULL_HANDLER = new URLStreamHandler() {
1196         public URLConnection openConnection(URL u) { return null; }
1197         public URLConnection openConnection(URL u, Proxy p)  { return null; }
1198     };
1199 
1200     /** Returns a handler instance for the given protocol, null if the factories
1201      *  could not create a handler, or NULL_HANDLER if there are no factories.
1202      */
1203     private static URLStreamHandler handlerFromSettableFactory(String protocol) {
1204         URLStreamHandler handler = NULL_HANDLER;
1205         // Use the factory (if any). Volatile read makes
1206         // URLStreamHandlerFactory appear fully initialized to current thread.
1207         URLStreamHandlerFactory fac = factory;
1208         if (fac != null)
1209             handler = fac.createURLStreamHandler(protocol);
1210 
1211         if (handler == NULL_HANDLER || handler == null) {
1212             for (URLStreamHandlerFactory f : factoryList) {
1213                 handler = f.createURLStreamHandler(protocol);
1214                 if (handler != null)
1215                     return handler;
1216             }
1217         }
1218         return handler;
1219     }
1220 
1221     // installed service providers
1222     private static volatile List<URLStreamHandlerFactory> installedProviders;
1223     private static final Object providersLock = new Object();
1224     private static boolean loadingProviders  = false;
1225 
1226     private static List<URLStreamHandlerFactory> loadInstalledProviders() {
1227         List<URLStreamHandlerFactory> list = new ArrayList<>();
1228         ServiceLoader<URLStreamHandlerFactory> sl = ServiceLoader
1229                 .load(URLStreamHandlerFactory.class, ClassLoader.getSystemClassLoader());
1230         // ServiceConfigurationError may be throw here
1231         for (URLStreamHandlerFactory provider: sl)
1232             list.add(provider);
1233 
1234         return list;
1235     }
1236 
1237     private static List<URLStreamHandlerFactory> installedProviders() {
1238         if (installedProviders == null) {
1239             synchronized (providersLock) {
1240                 if (installedProviders == null) {
1241                     if (loadingProviders) {
1242                         throw new Error(
1243                             "Circular loading of URL stream handler providers detected");
1244                     }
1245                     loadingProviders = true;
1246 
1247                     // do not use a lambda, or method ref here.
1248                     List<URLStreamHandlerFactory> list = AccessController
1249                         .doPrivileged(new PrivilegedAction<List<URLStreamHandlerFactory>>() {
1250                             public List<URLStreamHandlerFactory> run() {
1251                                 return URL.loadInstalledProviders();
1252                             }
1253                         });
1254 
1255                     installedProviders = Collections.unmodifiableList(list);
1256                 }
1257             }
1258         }
1259         return installedProviders;
1260     }
1261 
1262     private static final String SL_SKIP_PROTOCOL = "jar";

1263 
1264     private static URLStreamHandler handlerFromInstalledProviders(String protocol) {
1265         if (protocol.equalsIgnoreCase(SL_SKIP_PROTOCOL))
1266             return null;
1267 
1268         URLStreamHandler handler = null;
1269         for (URLStreamHandlerFactory f : installedProviders()) {
1270             handler = f.createURLStreamHandler(protocol);
1271             if (handler != null)
1272                 return handler;







1273         }
1274         return handler;
1275     }
1276 
1277     private static final String[] UNOVERRIDEABLE_PROTOCOLS = {"file", "jrt"};
1278     private static boolean overrideable(String protocol) {
1279         for (String p : UNOVERRIDEABLE_PROTOCOLS)
1280             if (protocol.equalsIgnoreCase(p))
1281                 return false;
1282         return true;
1283     }
1284 
1285     /**
1286      * A table of protocol handlers.
1287      */
1288     static Hashtable<String,URLStreamHandler> handlers = new Hashtable<>();
1289     private static final Object streamHandlerLock = new Object();
1290 
1291     /**
1292      * Returns the Stream Handler.
1293      * @param protocol the protocol to use
1294      */
1295     static URLStreamHandler getURLStreamHandler(String protocol) {
1296 
1297         URLStreamHandler handler = handlers.get(protocol);
1298 
1299         if (handler != null)
1300             return handler;
1301 
1302         boolean checkedWithFactory = false;
1303 
1304         if (overrideable(protocol)) {
1305             handler = handlerFromSettableFactory(protocol);
1306             if (handler != NULL_HANDLER)
1307                 checkedWithFactory = true;
1308 
1309             if (handler == null || handler == NULL_HANDLER) {
1310                 handler = handlerFromInstalledProviders(protocol);
1311             }
1312         }
1313         if (handler == null) {
1314             // Try the built-in protocol handler
1315             handler = defaultFactory.createURLStreamHandler(protocol);
1316         }
1317 
1318         synchronized (streamHandlerLock) {
1319 
1320             URLStreamHandler handler2 = null;
1321 
1322             // Check again with hashtable just in case another
1323             // thread created a handler since we last checked
1324             handler2 = handlers.get(protocol);
1325 
1326             if (handler2 != null) {
1327                 return handler2;
1328             }
1329 
1330             // Check with factory if another thread set a
1331             // factory since our last check
1332             if (!checkedWithFactory) {
1333                 handler2 = handlerFromSettableFactory(protocol);
1334             }
1335 
1336             if (!(handler2 == null || handler2 == NULL_HANDLER)) {
1337                 // The handler from the factory must be given more
1338                 // importance. Discard the default handler that
1339                 // this thread created.
1340                 handler = handler2;
1341             }
1342 
1343             // Insert this handler into the hashtable
1344             if (handler != null) {
1345                 handlers.put(protocol, handler);
1346             }
1347 
1348         }

1349 
1350         return handler;

1351     }










1352 
1353     /**
1354      * WriteObject is called to save the state of the URL to an
1355      * ObjectOutputStream. The handler is not saved since it is
1356      * specific to this system.
1357      *
1358      * @serialData the default write object value. When read back in,
1359      * the reader must ensure that calling getURLStreamHandler with
1360      * the protocol variable returns a valid URLStreamHandler and
1361      * throw an IOException if it does not.
1362      */
1363     private synchronized void writeObject(java.io.ObjectOutputStream s)
1364         throws IOException
1365     {
1366         s.defaultWriteObject(); // write the fields
1367     }
1368 
1369     /**
1370      * readObject is called to restore the state of the URL from the
1371      * stream.  It reads the components of the URL and finds the local
1372      * stream handler.
1373      */
1374     private synchronized void readObject(java.io.ObjectInputStream s)
1375          throws IOException, ClassNotFoundException
1376     {
1377         s.defaultReadObject();  // read the fields
1378         if ((handler = getURLStreamHandler(protocol)) == null) {
1379             throw new IOException("unknown protocol: " + protocol);
1380         }
1381 
1382         // Construct authority part
1383         if (authority == null &&
1384             ((host != null && host.length() > 0) || port != -1)) {
1385             if (host == null)
1386                 host = "";
1387             authority = (port == -1) ? host : host + ":" + port;
1388 
1389             // Handle hosts with userInfo in them
1390             int at = host.lastIndexOf('@');
1391             if (at != -1) {
1392                 userInfo = host.substring(0, at);
1393                 host = host.substring(at+1);
1394             }
1395         } else if (authority != null) {
1396             // Construct user info part
1397             int ind = authority.indexOf('@');
1398             if (ind != -1)
1399                 userInfo = authority.substring(0, ind);
1400         }
1401 
1402         // Construct path and query part
1403         path = null;
1404         query = null;
1405         if (file != null) {
1406             // Fix: only do this if hierarchical?
1407             int q = file.lastIndexOf('?');
1408             if (q != -1) {
1409                 query = file.substring(q+1);
1410                 path = file.substring(0, q);
1411             } else
1412                 path = file;
1413         }
1414     }
1415 }
1416 
1417 class Parts {
1418     String path, query, ref;
1419 
1420     Parts(String file) {
1421         int ind = file.indexOf('#');
1422         ref = ind < 0 ? null: file.substring(ind + 1);
1423         file = ind < 0 ? file: file.substring(0, ind);
1424         int q = file.lastIndexOf('?');
1425         if (q != -1) {
1426             query = file.substring(q+1);
1427             path = file.substring(0, q);
1428         } else {
1429             path = file;
1430         }
1431     }
1432 
1433     String getPath() {
1434         return path;
1435     }
1436 
1437     String getQuery() {
1438         return query;
1439     }
1440 
1441     String getRef() {
1442         return ref;
1443     }
1444 }
--- EOF ---