RFR: 8267670: Update java.io, java.math, and java.text to use switch expressions [v2]

[Patrick Concannon]

On Tue, 25 May 2021 12:31:38 GMT, Chris Hegarty <chegar at openjdk.org> wrote:

>> Patrick Concannon has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
>> 
>>  - 8267670: Updated code to use yield
>>  - Merge remote-tracking branch 'origin/master' into JDK-8267670
>>  - 8267670: Update java.io, java.math, and java.text to use switch expressions
>
> src/java.base/share/classes/java/io/ObjectInputStream.java line 1877:
> 
>> 1875:                 descriptor.checkInitialized();
>> 1876:             }
>> 1877:             default                 -> throw new StreamCorruptedException(
> 
> What would you think of assigning descriptor with the value returned from evaluating the switch?
> 
> Either:
> 
> 1) 
> 
> ObjectStreamClass descriptor = switch (tc) {
>         case TC_NULL            -> (ObjectStreamClass) readNull();
>         case TC_PROXYCLASSDESC  -> readProxyDesc(unshared);
>         case TC_CLASSDESC       -> readNonProxyDesc(unshared);
>         case TC_REFERENCE       -> readAndCheckHandle(unshared);
>         default -> throw new StreamCorruptedException(String.format("invalid type code: %02X", tc));
>     };
>     return descriptor;
> }
> 
> , where the body of TC_REFERENCE is enclosed in readAndCheckHandle,   OR
> 
> 2) Simply 
> 
>   case TC_REFERENCE       -> {
>         var d = (ObjectStreamClass)readHandle(unshared);
>         // Should only reference initialized class descriptors
>         d.checkInitialized();
>         yield d; }

Code updated as suggested. See adc8af4

> src/java.base/share/classes/java/io/StreamTokenizer.java line 795:
> 
>> 793:                  * case statements
>> 794:                  */
>> 795:                 if (ttype < 256 && ((ctype[ttype] & CT_QUOTE) != 0)) {
> 
> Maybe (since its easier to grok the yield rather than the assignment of ret in branches):
> 
>     String ret = switch (ttype) {
>             case TT_EOF     -> "EOF";
>             case TT_EOL     -> "EOL";
>             case TT_WORD    -> sval;
>             case TT_NUMBER  -> "n=" + nval;
>             case TT_NOTHING -> "NOTHING";
>             default         -> {
>                 /*
>                  * ttype is the first character of either a quoted string or
>                  * is an ordinary character. ttype can definitely not be less
>                  * than 0, since those are reserved values used in the previous
>                  * case statements
>                  */
>                 if (ttype < 256 && ((ctype[ttype] & CT_QUOTE) != 0)) {
>                     yield sval;
>                 }
>                 char s[] = new char[3];
>                 s[0] = s[2] = ''';
>                 s[1] = (char) ttype;
>                 yield new String(s);
>             }
>         };
>         return "Token[" + ret + "], line " + LINENO;

Code updated as suggested. See adc8af4

-------------

PR: https://git.openjdk.java.net/jdk/pull/4182