Re: 回复：Adding appendHex method to StringBuilder

[Roger Riggs]

Hi,

The j.u.HexFormat class has methods that append hex formatted byte 
arrays to an Appendable such as StringBuilder.

The `toHexDigits` methods return strings with the hex values of byte, 
short, char, int, and long.

Similar `formatHex` methods could be added with an Appendable argument 
would keep the focus in HexFormat for the formatting but allows the 
result to be placed directly in a StringBuilder.

For example in this draft PR. https://github.com/openjdk/jdk/pull/16105

Regards, Roger


On 10/2/23 10:01 AM, 温绍锦(高铁) wrote:
> StringTemplate is great and I wish I can submit PR to improve it. But 
> I still think StringBuilder.appendHex is a basic API, not a formatted 
> API. Just like Integer.toHexString and Long.toHexString, they are very 
> commonly used and should be built-in.
>
>     ------------------------------------------------------------------
>     发件人：温绍锦(高铁) <shaojin.wensj at alibaba-inc.com>
>     发送时间：2023年10月2日(星期一) 20:46
>     收件人：Mark Reinhold <mark.reinhold at oracle.com>; Claes Redestad
>     <claes.redestad at oracle.com>
>     抄　送：core-libs-dev at openjdk.org <core-libs-dev at openjdk.org>
>     主　题：回复：Adding appendHex method to StringBuilder
>
>     Using String Template FMT has better performance and better code
>     readability. But String Template does not yet support
>     for/while/if/switch. Is there any plan to enhance String Template
>     to support for/while/if/switch? The following scenarios cannot be
>     implemented using String.format or String Template. I think
>     whether to build in support for foo(bar(x)) depends on whether it
>     is a common enough method.
>
>     ```java
>     package java.net;
>     class Inet6Address extends InetAddress {
>         static String numericToTextFormat(byte[] src) {
>             StringBuilder sb = new StringBuilder(39);
>             for (int i = 0; i < (INADDRSZ / INT16SZ); i++) {
>     sb.append(Integer.toHexString(((src[i<<1]<<8) & 0xff00)
>               | (src[(i<<1)+1] & 0xff)));
>                 if (i < (INADDRSZ / INT16SZ) -1 ) {
>                   sb.append(":");
>                 }
>             }
>             return sb.toString();
>         }
>     }
>     class SocketPermission {
>       private boolean authorizedIPv6(String cname, byte[] addr) {
>             String authHost = "";
>             InetAddress auth;
>             try {
>                 StringBuilder sb = new StringBuilder(39);
>                 for (int i = 15; i >= 0; i--) {
>     sb.append(Integer.toHexString(((addr[i]) & 0x0f)));
>                     sb.append('.');
>     sb.append(Integer.toHexString(((addr[i] >> 4) & 0x0f)));
>                     sb.append('.');
>                 }
>             ...
>       }
>     }
>     ```
>     ```java
>     package sun.security.krb5.internal.crypto.dk;
>     class DkCrypto {
>         static String bytesToString(byte[] digest) {
>             // Get character representation of digest
>             StringBuilder digestString = new StringBuilder();
>             for (int i = 0; i < digest.length; i++) {
>                 if ((digest[i] & 0x000000ff) < 0x10) {
>     digestString.append('0').append(Integer.toHexString(digest[i] &
>     0x000000ff));
>                 } else {
>     digestString.append(
>     Integer.toHexString(digest[i] & 0x000000ff));
>                 }
>             }
>             return digestString.toString();
>         }
>     }
>     ```
>
>     - wenshao
>
>     ------------------------------------------------------------------
>     发件人：Mark Reinhold <mark.reinhold at oracle.com>
>     发送时间：2023年10月2日(星期一) 20:19
>     收件人：Claes Redestad <claes.redestad at oracle.com>
>     抄　送：温绍锦(高铁) <shaojin.wensj at alibaba-inc.com>;
>     core-libs-dev at openjdk.org <core-libs-dev at openjdk.org>
>     主　题：Re: Adding appendHex method to StringBuilder
>
>     2023/10/2 7:22:55 -0400, claes.redestad at oracle.com:
>     > I think this goes against the grain: StringBuilder is a simple
>     builder
>     > for non-localized unformatted output. For formatted output there’s
>     > Formatter, String.format and, with JEP 430[1], FMT."..." to help
>     output
>     > string data in more advanced, formatted and localized ways.
>
>     Agreed.
>
>     If we were to introduce a `fooBar(x)` method for every common
>     `foo(bar(x))` expression in the JDK code base then our APIs
>     would fast become inscrutable.
>
>     - Mark
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/core-libs-dev/attachments/20231009/e55cf8f4/attachment-0001.htm>