It’s possible to build up and combine unprocessed RAW template snippets, then
combine and process them together:
static int[] val = new int[] { 2048, 31337, 0xbeefcace, 9000, 4711, 1337, 2100,
2600 };
@Benchmark
public String toStringFMTCombineHex8() {
var templates = new ArrayList<StringTemplate>();
for (int i = 0; i < 8; i++) {
int h = val[i];
templates.add(RAW."%x\{h}");
}
return StringTemplate.combine(templates).process(FMT);
}
Performance is… not great, but I think we can and should work on that:
Benchmark Mode Cnt Score Error Units
StringBuilders.toStringFMTCombineHex8 avgt 15 2421,151 ± 646,501 ns/op
/Claes
2 okt. 2023 kl. 14:46 skrev 温绍锦(高铁) <shaojin.we...@alibaba-inc.com>:
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.reinh...@oracle.com>
发送时间：2023年10月2日(星期一) 20:19
收件人：Claes Redestad <claes.redes...@oracle.com>
抄 送：温绍锦(高铁) <shaojin.we...@alibaba-inc.com>; core-libs-dev@openjdk.org
<core-libs-dev@openjdk.org>
主 题：Re: Adding appendHex method to StringBuilder
2023/10/2 7:22:55 -0400, claes.redes...@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
