On Fri, 5 Feb 2021 10:03:09 GMT, Serguei Spitsyn <sspit...@openjdk.org> wrote:
>> One implementation is in the JVM itself, to be used when the JVM is still
>> running well, and not just from command line tools. Heap dumping can also be
>> triggered by the JVM itslef by setting flags like -XX:+HeapDumpBeforeFullGC.
>> The other implementation is in SA, to be used on a core file or a hung JVM
>> process, although it can also be used on a JVM that is still running well.
>> BTW, there used to be a 3rd implementation. The old hprof profiler (a JVMTI
>> agent) also was used to generate hprof files.
>
> Hi Lin,
>
> A week ago you replied that you are accepting the following suggested
> refactoring:
>
> /*
> * Possible commands:
> * dumpheap gz=1 file
> * dumpheap gz=1
> * dumpheap file
> * dumpheap
> *
> * Use default filename if cntTokens == 0.
> * Handle cases with cntTokens == 1 or 2.
> */
>
> if (cntTokens > 2) {
> err.println("Too big number of options: " +
> cntTokens);
> usage();
> return;
> }
> if (cntTokens >= 1) { // parse first argument which is
> "gz=" option
> String option = t.nextToken();
> gzlevel = parseHeapDumpCompressionLevel(option);
> if (gzlevel == 0) {
> usage();
> return;
> }
> filename = "heap.bin.gz";
> }
> if (cntTokens == 2) { // parse second argument which is
> filename
> filename = t.nextToken();
> if (filename.startsWith("gz=")) {
> err.println("Filename should not start with
> "gz=": " + filename);
> usage();
> return;
> }
> }
>
> But I still do not see it in the latest updates from you. It feels like there
> is some misunderstanding and confusion.
> Could you, please, clear this up?
>
> Thanks,
> Serguei
Also, this method can be refactored to something like this (the check for
exactly one option argument is needed):
private int parseHeapDumpCompressionLevel(String option) {
int gzl = 0;
String[] keyValue = option.split("=");
assert keyValue[0].equals("gz") : "expected option to start from gz=";
if (keyValue.length != 2) {
err.println("Exactly one argument is expected for option "gz"");
return 0;
}
String level = keyValue[1];
try {
gzl = Integer.parseInt(level);
} catch (NumberFormatException e) {
err.println("gz option value not an integer ("+level+")");
return 0;
}
if (gzl < 1 || gzl > 9) {
err.println("Compression level out of range (1-9): " + level);
return 0;
}
return gzl;
}
-------------
PR: https://git.openjdk.java.net/jdk/pull/1712
