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src/java.base/share/classes/java/nio/charset/Charset.java

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 318 
 319     /* The standard set of charsets */
 320     private static CharsetProvider standardProvider = new StandardCharsets();
 321 
 322     // Cache of the most-recently-returned charsets,
 323     // along with the names that were used to find them
 324     //
 325     private static volatile Object[] cache1 = null; // "Level 1" cache
 326     private static volatile Object[] cache2 = null; // "Level 2" cache
 327 
 328     private static void cache(String charsetName, Charset cs) {
 329         cache2 = cache1;
 330         cache1 = new Object[] { charsetName, cs };
 331     }
 332 
 333     // Creates an iterator that walks over the available providers, ignoring
 334     // those whose lookup or instantiation causes a security exception to be
 335     // thrown.  Should be invoked with full privileges.
 336     //
 337     private static Iterator<CharsetProvider> providers() {
 338         return new Iterator<CharsetProvider>() {
 339 
 340                 ClassLoader cl = ClassLoader.getSystemClassLoader();
 341                 ServiceLoader<CharsetProvider> sl =
 342                     ServiceLoader.load(CharsetProvider.class, cl);
 343                 Iterator<CharsetProvider> i = sl.iterator();
 344 
 345                 CharsetProvider next = null;
 346 
 347                 private boolean getNext() {
 348                     while (next == null) {
 349                         try {
 350                             if (!i.hasNext())
 351                                 return false;
 352                             next = i.next();
 353                         } catch (ServiceConfigurationError sce) {
 354                             if (sce.getCause() instanceof SecurityException) {
 355                                 // Ignore security exceptions
 356                                 continue;
 357                             }
 358                             throw sce;


 387     private static Charset lookupViaProviders(final String charsetName) {
 388 
 389         // The runtime startup sequence looks up standard charsets as a
 390         // consequence of the VM's invocation of System.initializeSystemClass
 391         // in order to, e.g., set system properties and encode filenames.  At
 392         // that point the application class loader has not been initialized,
 393         // however, so we can't look for providers because doing so will cause
 394         // that loader to be prematurely initialized with incomplete
 395         // information.
 396         //
 397         if (!sun.misc.VM.isBooted())
 398             return null;
 399 
 400         if (gate.get() != null)
 401             // Avoid recursive provider lookups
 402             return null;
 403         try {
 404             gate.set(gate);
 405 
 406             return AccessController.doPrivileged(
 407                 new PrivilegedAction<Charset>() {
 408                     public Charset run() {
 409                         for (Iterator<CharsetProvider> i = providers();
 410                              i.hasNext();) {
 411                             CharsetProvider cp = i.next();
 412                             Charset cs = cp.charsetForName(charsetName);
 413                             if (cs != null)
 414                                 return cs;
 415                         }
 416                         return null;
 417                     }
 418                 });
 419 
 420         } finally {
 421             gate.set(null);
 422         }
 423     }
 424 
 425     /* The extended set of charsets */
 426     private static class ExtendedProviderHolder {
 427         static final CharsetProvider extendedProvider = extendedProvider();
 428         // returns ExtendedProvider, if installed
 429         private static CharsetProvider extendedProvider() {
 430             return AccessController.doPrivileged(
 431                        new PrivilegedAction<CharsetProvider>() {
 432                            public CharsetProvider run() {
 433                                 try {
 434                                     Class<?> epc
 435                                         = Class.forName("sun.nio.cs.ext.ExtendedCharsets");
 436                                     return (CharsetProvider)epc.newInstance();
 437                                 } catch (ClassNotFoundException x) {
 438                                     // Extended charsets not available
 439                                     // (charsets.jar not present)
 440                                 } catch (InstantiationException |
 441                                          IllegalAccessException x) {
 442                                   throw new Error(x);
 443                                 }
 444                                 return null;
 445                             }
 446                         });
 447         }
 448     }
 449 
 450     private static Charset lookupExtendedCharset(String charsetName) {
 451         CharsetProvider ecp = ExtendedProviderHolder.extendedProvider;


 553      *
 554      * <p> The invocation of this method, and the subsequent use of the
 555      * resulting map, may cause time-consuming disk or network I/O operations
 556      * to occur.  This method is provided for applications that need to
 557      * enumerate all of the available charsets, for example to allow user
 558      * charset selection.  This method is not used by the {@link #forName
 559      * forName} method, which instead employs an efficient incremental lookup
 560      * algorithm.
 561      *
 562      * <p> This method may return different results at different times if new
 563      * charset providers are dynamically made available to the current Java
 564      * virtual machine.  In the absence of such changes, the charsets returned
 565      * by this method are exactly those that can be retrieved via the {@link
 566      * #forName forName} method.  </p>
 567      *
 568      * @return An immutable, case-insensitive map from canonical charset names
 569      *         to charset objects
 570      */
 571     public static SortedMap<String,Charset> availableCharsets() {
 572         return AccessController.doPrivileged(
 573             new PrivilegedAction<SortedMap<String,Charset>>() {
 574                 public SortedMap<String,Charset> run() {
 575                     TreeMap<String,Charset> m =
 576                         new TreeMap<String,Charset>(
 577                             ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);
 578                     put(standardProvider.charsets(), m);
 579                     CharsetProvider ecp = ExtendedProviderHolder.extendedProvider;
 580                     if (ecp != null)
 581                         put(ecp.charsets(), m);
 582                     for (Iterator<CharsetProvider> i = providers(); i.hasNext();) {
 583                         CharsetProvider cp = i.next();
 584                         put(cp.charsets(), m);
 585                     }
 586                     return Collections.unmodifiableSortedMap(m);
 587                 }
 588             });
 589     }
 590 
 591     private static volatile Charset defaultCharset;
 592 
 593     /**
 594      * Returns the default charset of this Java virtual machine.
 595      *
 596      * <p> The default charset is determined during virtual-machine startup and


 646     }
 647 
 648     /**
 649      * Returns this charset's canonical name.
 650      *
 651      * @return  The canonical name of this charset
 652      */
 653     public final String name() {
 654         return name;
 655     }
 656 
 657     /**
 658      * Returns a set containing this charset's aliases.
 659      *
 660      * @return  An immutable set of this charset's aliases
 661      */
 662     public final Set<String> aliases() {
 663         if (aliasSet != null)
 664             return aliasSet;
 665         int n = aliases.length;
 666         HashSet<String> hs = new HashSet<String>(n);
 667         for (int i = 0; i < n; i++)
 668             hs.add(aliases[i]);
 669         aliasSet = Collections.unmodifiableSet(hs);
 670         return aliasSet;
 671     }
 672 
 673     /**
 674      * Returns this charset's human-readable name for the default locale.
 675      *
 676      * <p> The default implementation of this method simply returns this
 677      * charset's canonical name.  Concrete subclasses of this class may
 678      * override this method in order to provide a localized display name. </p>
 679      *
 680      * @return  The display name of this charset in the default locale
 681      */
 682     public String displayName() {
 683         return name;
 684     }
 685 
 686     /**




 318 
 319     /* The standard set of charsets */
 320     private static CharsetProvider standardProvider = new StandardCharsets();
 321 
 322     // Cache of the most-recently-returned charsets,
 323     // along with the names that were used to find them
 324     //
 325     private static volatile Object[] cache1 = null; // "Level 1" cache
 326     private static volatile Object[] cache2 = null; // "Level 2" cache
 327 
 328     private static void cache(String charsetName, Charset cs) {
 329         cache2 = cache1;
 330         cache1 = new Object[] { charsetName, cs };
 331     }
 332 
 333     // Creates an iterator that walks over the available providers, ignoring
 334     // those whose lookup or instantiation causes a security exception to be
 335     // thrown.  Should be invoked with full privileges.
 336     //
 337     private static Iterator<CharsetProvider> providers() {
 338         return new Iterator<>() {
 339 
 340                 ClassLoader cl = ClassLoader.getSystemClassLoader();
 341                 ServiceLoader<CharsetProvider> sl =
 342                     ServiceLoader.load(CharsetProvider.class, cl);
 343                 Iterator<CharsetProvider> i = sl.iterator();
 344 
 345                 CharsetProvider next = null;
 346 
 347                 private boolean getNext() {
 348                     while (next == null) {
 349                         try {
 350                             if (!i.hasNext())
 351                                 return false;
 352                             next = i.next();
 353                         } catch (ServiceConfigurationError sce) {
 354                             if (sce.getCause() instanceof SecurityException) {
 355                                 // Ignore security exceptions
 356                                 continue;
 357                             }
 358                             throw sce;


 387     private static Charset lookupViaProviders(final String charsetName) {
 388 
 389         // The runtime startup sequence looks up standard charsets as a
 390         // consequence of the VM's invocation of System.initializeSystemClass
 391         // in order to, e.g., set system properties and encode filenames.  At
 392         // that point the application class loader has not been initialized,
 393         // however, so we can't look for providers because doing so will cause
 394         // that loader to be prematurely initialized with incomplete
 395         // information.
 396         //
 397         if (!sun.misc.VM.isBooted())
 398             return null;
 399 
 400         if (gate.get() != null)
 401             // Avoid recursive provider lookups
 402             return null;
 403         try {
 404             gate.set(gate);
 405 
 406             return AccessController.doPrivileged(
 407                 new PrivilegedAction<>() {
 408                     public Charset run() {
 409                         for (Iterator<CharsetProvider> i = providers();
 410                              i.hasNext();) {
 411                             CharsetProvider cp = i.next();
 412                             Charset cs = cp.charsetForName(charsetName);
 413                             if (cs != null)
 414                                 return cs;
 415                         }
 416                         return null;
 417                     }
 418                 });
 419 
 420         } finally {
 421             gate.set(null);
 422         }
 423     }
 424 
 425     /* The extended set of charsets */
 426     private static class ExtendedProviderHolder {
 427         static final CharsetProvider extendedProvider = extendedProvider();
 428         // returns ExtendedProvider, if installed
 429         private static CharsetProvider extendedProvider() {
 430             return AccessController.doPrivileged(
 431                        new PrivilegedAction<>() {
 432                            public CharsetProvider run() {
 433                                 try {
 434                                     Class<?> epc
 435                                         = Class.forName("sun.nio.cs.ext.ExtendedCharsets");
 436                                     return (CharsetProvider)epc.newInstance();
 437                                 } catch (ClassNotFoundException x) {
 438                                     // Extended charsets not available
 439                                     // (charsets.jar not present)
 440                                 } catch (InstantiationException |
 441                                          IllegalAccessException x) {
 442                                   throw new Error(x);
 443                                 }
 444                                 return null;
 445                             }
 446                         });
 447         }
 448     }
 449 
 450     private static Charset lookupExtendedCharset(String charsetName) {
 451         CharsetProvider ecp = ExtendedProviderHolder.extendedProvider;


 553      *
 554      * <p> The invocation of this method, and the subsequent use of the
 555      * resulting map, may cause time-consuming disk or network I/O operations
 556      * to occur.  This method is provided for applications that need to
 557      * enumerate all of the available charsets, for example to allow user
 558      * charset selection.  This method is not used by the {@link #forName
 559      * forName} method, which instead employs an efficient incremental lookup
 560      * algorithm.
 561      *
 562      * <p> This method may return different results at different times if new
 563      * charset providers are dynamically made available to the current Java
 564      * virtual machine.  In the absence of such changes, the charsets returned
 565      * by this method are exactly those that can be retrieved via the {@link
 566      * #forName forName} method.  </p>
 567      *
 568      * @return An immutable, case-insensitive map from canonical charset names
 569      *         to charset objects
 570      */
 571     public static SortedMap<String,Charset> availableCharsets() {
 572         return AccessController.doPrivileged(
 573             new PrivilegedAction<>() {
 574                 public SortedMap<String,Charset> run() {
 575                     TreeMap<String,Charset> m =
 576                         new TreeMap<>(
 577                             ASCIICaseInsensitiveComparator.CASE_INSENSITIVE_ORDER);
 578                     put(standardProvider.charsets(), m);
 579                     CharsetProvider ecp = ExtendedProviderHolder.extendedProvider;
 580                     if (ecp != null)
 581                         put(ecp.charsets(), m);
 582                     for (Iterator<CharsetProvider> i = providers(); i.hasNext();) {
 583                         CharsetProvider cp = i.next();
 584                         put(cp.charsets(), m);
 585                     }
 586                     return Collections.unmodifiableSortedMap(m);
 587                 }
 588             });
 589     }
 590 
 591     private static volatile Charset defaultCharset;
 592 
 593     /**
 594      * Returns the default charset of this Java virtual machine.
 595      *
 596      * <p> The default charset is determined during virtual-machine startup and


 646     }
 647 
 648     /**
 649      * Returns this charset's canonical name.
 650      *
 651      * @return  The canonical name of this charset
 652      */
 653     public final String name() {
 654         return name;
 655     }
 656 
 657     /**
 658      * Returns a set containing this charset's aliases.
 659      *
 660      * @return  An immutable set of this charset's aliases
 661      */
 662     public final Set<String> aliases() {
 663         if (aliasSet != null)
 664             return aliasSet;
 665         int n = aliases.length;
 666         HashSet<String> hs = new HashSet<>(n);
 667         for (int i = 0; i < n; i++)
 668             hs.add(aliases[i]);
 669         aliasSet = Collections.unmodifiableSet(hs);
 670         return aliasSet;
 671     }
 672 
 673     /**
 674      * Returns this charset's human-readable name for the default locale.
 675      *
 676      * <p> The default implementation of this method simply returns this
 677      * charset's canonical name.  Concrete subclasses of this class may
 678      * override this method in order to provide a localized display name. </p>
 679      *
 680      * @return  The display name of this charset in the default locale
 681      */
 682     public String displayName() {
 683         return name;
 684     }
 685 
 686     /**


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