I have some Java app using Spring Batch. I've got a table used as a queue which contains information on jobs that were requested by clients (as a client requests for a task to be executed, a row is added to this queue).
In one of my classes a while loop is run until someone deactivates some flag :
protected void runJobLaunchingLoop() {
while (!isTerminated()) {
try {
if (isActivated()) {
QueueEntryDTO queueEntry = dequeueJobEntry();
launchJob(queueEntry);
}
}
catch (EmptyQueueException ignored) {}
catch (Exception exception) {
logger.error("There was a problem while de-queuing a job ('" + exception.getMessage() + "').");
}
finally {
pauseProcessor();
}
}
}
The pauseProcessor() method calls Thread.sleep(). When I run this app in a Docker container it looks like the number of threads run by the application keep on increasing. The threads have the name "Timer-X" with X some integer that auto-increments.
I looked at the stack trace of one of these :
"Timer-14" - Thread t#128
java.lang.Thread.State: WAITING
at java.base#11.0.6/java.lang.Object.wait(Native Method)
- waiting on <25e60c31> (a java.util.TaskQueue)
at java.base#11.0.6/java.lang.Object.wait(Unknown Source)
at java.base#11.0.6/java.util.TimerThread.mainLoop(Unknown Source)
- locked <25e60c31> (a java.util.TaskQueue)
at java.base#11.0.6/java.util.TimerThread.run(Unknown Source)
Locked ownable synchronizers:
- None
Any idea what could be the cause of this? I'm not sure but if I don't run the app in a container but locally from IntelliJ, it seems like the problem does not occur. I'm not sure because sometimes it takes a while before thread count starts increasing.
EDIT : Some relevant code ...
protected QueueEntryDTO dequeueJobEntry() {
Collection<QueueEntryDTO> collection = getQueueService().dequeueEntry();
if (collection.isEmpty())
throw new EmptyQueueException();
return collection.iterator().next();
}
#Transactional
public Collection<QueueEntryDTO> dequeueEntry() {
Optional<QueueEntry> optionalEntry = this.queueEntryDAO.findTopByStatusCode(QueueStatusEnum.WAITING.getStatusCode());
if (optionalEntry.isPresent()) {
QueueEntry entry = (QueueEntry)optionalEntry.get();
QueueEntry updatedEntry = this.saveEntryStatus(entry, QueueStatusEnum.PROCESSING, (String)null);
return Collections.singleton(this.queueEntryDTOMapper.toDTO(updatedEntry));
} else {
return new ArrayList();
}
}
private void pauseProcessor() {
try {
Long sleepDuration = generalProperties.getQueueProcessingSleepDuration();
sleepDuration = Objects.requireNonNullElseGet(
sleepDuration,
() -> Double.valueOf(Math.pow(2.0, getRetries()) * 1000.0).longValue());
Thread.sleep(sleepDuration);
if (getRetries() < 4)
setRetries(getRetries() + 1);
}
catch (Exception ignored) {
logger.warn("Failed to pause job queue processor.");
}
}
It seems like this was caused by a bug that was resolved in a more recent version of DB2 than I was using.
Applications are getting large number of timer threads when API
timerLevelforQueryTimeout value is not set explicitly in an
application using JCC driver version 11.5 GA (JCC 4.26.14) or
later.
This issue is fixed in 11.5 M4 FP0(JCC 4.27.25).
I updated the version to a newer one (11.5.6) in my POM file, but this didn't fix the issue. Turns out my K8s pod was still using 11.5.0 and Maven acted weird. I then applied this technique (using dependencyManagement in the POM file) and the newer version was loaded.
I'm having problems handling callbacks in JNA.
I'm trying to use a C API that uses callbacks to handle several session events (logged in, logged out, connection problem...).
The session object (called sp_session) is an opaque struct. All the callbacks are registered in a sp_session_callbacks structure. According to the API, I am supposed to declare the callbacks object, and put it into a Config object that I will provide when creating the sp_session object. If I don't want to use certain callbacks, I am supposed to initialize them with null. The API is using the __stdcall calling convention.
Here is a snippet of the C header that's relevant to my problem:
#define SP_CALLCONV __stdcall
typedef struct sp_session sp_session; ///< Representation of a session
typedef enum sp_error {
SP_ERROR_OK = 0,
SP_ERROR_BAD_API_VERSION = 1,
/* More errors */
} sp_error;
typedef struct sp_session_callbacks {
/**
* Called when login has been processed and was successful
*/
void (SP_CALLCONV *logged_in)(sp_session *session, sp_error error);
/**
* Called when logout has been processed. Either called explicitly
* if you initialize a logout operation, or implicitly if there
* is a permanent connection error
*
* #param[in] session Session
*/
void (SP_CALLCONV *logged_out)(sp_session *session);
/**
* Called when there is a connection error, and the library has problems
* reconnecting to the Spotify service. Could be called multiple times (as
* long as the problem is present)
*/
void (SP_CALLCONV *connection_error)(sp_session *session, sp_error error);
/* More callbacks */
} sp_session_callbacks;
/**
* Initialize a session. The session returned will be initialized, but you will need
* to log in before you can perform any other operation
*/
SP_LIBEXPORT(sp_error) sp_session_create(const sp_session_config *config, sp_session **sess);
Here is my equivalent JNA code:
The sp_session object
public class sp_session extends PointerType{
public sp_session(Pointer address) {
super(address);
}
public sp_session() {
super();
}
}
The sp_session_callbacks object, containing all the callbacks
public class sp_session_callbacks extends Structure{
public LoggedIn logged_in;
public LoggedOut logged_out;
public ConnectionError connection_error;
}
The callbacks object (here is LoggedIn, but of course I have one for each callback)
public interface LoggedIn extends StdCallCallback {
public void logged_in(sp_session session, int error);
}
The native library, with the declaration of all the methods
public interface JLibspotify extends StdCallLibrary{
int sessionCreate(sp_session_config config, PointerByReference sess);
int sessionLogin(sp_session session, String username, String password);
// All the other methods defined by the API
}
And my main class, binding it all together
public class Test{
static{
System.loadLibrary("libspotify");
}
public static void main(String[] args){
JLibspotify lib = (JLibspotify)Native.loadLibrary("libspotify", JLibspotify.class);
sp_session_config cfg = new sp_session_config();
}
sp_session_callbacks sessCallbacks = new sp_session_callbacks();
LoggedIn loggedInCallback = new LoggedIn(){
public void logged_in(sp_session session, int error) {
System.out.println("logged_in() called");
}
};
sessCallbacks.logged_in = loggedInCallback;
cfg.session_callbacks = sessCallbacks;
PointerByReference sessionPbr = new PointerByReference();
int error_id = sessionCreate(cfg, sessionPbr); // CRASHES HERE
sp_session mySession = new sp_session(sessionPbr.getValue());
}
}
So, the sessionCreate function call makes the JRE crash with the trace at the end of the post EXCEPTION_ACCESS_VIOLATION (0xc0000005) problematic frame: C [jna3666290841889849729.dll+0xa3f4].
It looks like the logged_in callback is causing this, because when I set it to null it runs ok. Plus, if I initialize the connection_error callback, that has the exact same signature, it doesn't crash either.
I'm running version 3.2.7 of JNA. I tried with an anterior version (3.0.9) and it also failed.
I'm running the JDK 1.7 beta version, but I tried with the 1.6 and it also failed.
Thank you!
#
# A fatal error has been detected by the Java Runtime Environment:
#
# EXCEPTION_ACCESS_VIOLATION (0xc0000005) at pc=0x0499a3f4, pid=1368, tid=1344
#
# JRE version: 7.0-b129
# Java VM: Java HotSpot(TM) Client VM (21.0-b01 mixed mode, sharing windows-x86 )
# Problematic frame:
# C [jna3666290841889849729.dll+0xa3f4]
#
# If you would like to submit a bug report, please visit:
# http://java.sun.com/webapps/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.
#
--------------- T H R E A D ---------------
Current thread (0x01b79400): JavaThread "main" [_thread_in_native, id=1344, stack(0x00340000,0x00390000)]
siginfo: ExceptionCode=0xc0000005, reading address 0x1993053a
Registers:
EAX=0x19930522, EBX=0x100dc77c, ECX=0x00010004, EDX=0x1008d3e0
ESP=0x0038f58c, EBP=0x0038f5b4, ESI=0x0038f5a4, EDI=0x100b79b0
EIP=0x0499a3f4, EFLAGS=0x00210212
Top of Stack: (sp=0x0038f58c)
0x0038f58c: 100dc77c 0038f5a4 00010004 0038f688
0x0038f59c: 05983de0 05981330 0598289c 05983de0
0x0038f5ac: 05983de0 00000014 0038f688 1008d3ea
0x0038f5bc: 05983de0 10030d77 0038fc44 100b79b0
0x0038f5cc: ffffffff 1008d334 00000000 05983de0
0x0038f5dc: 1008d3e0 05983fc4 1008d9fd 0038f770
0x0038f5ec: 00000000 00000000 7275016a 055310b0
0x0038f5fc: 00000000 00010001 00000000 00000000
Instructions: (pc=0x0499a3f4)
0x0499a3d4: 01 00 89 e5 57 56 8d 75 f0 53 83 ec 1c 8b 7d 14
0x0499a3e4: 8b 5f 4c 8b 03 89 4c 24 08 89 74 24 04 89 1c 24
0x0499a3f4: ff 50 18 83 ec 0c 85 c0 0f 94 c0 0f b6 c0 85 c0
0x0499a404: 89 45 ec 75 19 8b 03 31 d2 89 54 24 08 89 74 24
Register to memory mapping:
EAX=0x19930522 is an unknown value
EBX=0x100dc77c is an unknown value
ECX=0x00010004 is an unknown value
EDX=0x1008d3e0 is an unknown value
ESP=0x0038f58c is pointing into the stack for thread: 0x01b79400
EBP=0x0038f5b4 is pointing into the stack for thread: 0x01b79400
ESI=0x0038f5a4 is pointing into the stack for thread: 0x01b79400
EDI=0x100b79b0 is an unknown value
Stack: [0x00340000,0x00390000], sp=0x0038f58c, free space=317k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [jna3666290841889849729.dll+0xa3f4] Java_com_sun_jna_Native_initialize_1ffi_1type+0x1054
C [libspotify.dll+0x8d3ea] sp_error_message+0x35a
C [jna3666290841889849729.dll+0xcb77] Java_com_sun_jna_Native_initialize_1ffi_1type+0x37d7
C [jna3666290841889849729.dll+0xc7c2] Java_com_sun_jna_Native_initialize_1ffi_1type+0x3422
C [jna3666290841889849729.dll+0x4561] Java_com_sun_jna_Pointer__1getString+0xa31
C [jna3666290841889849729.dll+0x4d2e] Java_com_sun_jna_Function_invokeInt+0x2e
j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0
j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315
j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214
j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341
j $Proxy0.sp_session_create(Lcom/nbarraille/jspotify/model/sp_session_config;Lcom/sun/jna/ptr/PointerByReference;)I+20
j com.nbarraille.jspotify.main.Test.main([Ljava/lang/String;)V+273
v ~StubRoutines::call_stub
V [jvm.dll+0x115f6d]
V [jvm.dll+0x1b788e]
V [jvm.dll+0x115fed]
V [jvm.dll+0xa2507]
V [jvm.dll+0xac867]
C [javaw.exe+0x209e]
C [javaw.exe+0xa23b]
C [javaw.exe+0xa2c5]
C [kernel32.dll+0x51194] BaseThreadInitThunk+0x12
C [ntdll.dll+0x5b429] RtlInitializeExceptionChain+0x63
C [ntdll.dll+0x5b3fc] RtlInitializeExceptionChain+0x36
Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
j com.sun.jna.Function.invokeInt(I[Ljava/lang/Object;)I+0
j com.sun.jna.Function.invoke([Ljava/lang/Object;Ljava/lang/Class;Z)Ljava/lang/Object;+315
j com.sun.jna.Function.invoke(Ljava/lang/Class;[Ljava/lang/Object;Ljava/util/Map;)Ljava/lang/Object;+214
j com.sun.jna.Library$Handler.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object;+341
j $Proxy0.sp_session_create(Lcom/nbarraille/jspotify/model/sp_session_config;Lcom/sun/jna/ptr/PointerByReference;)I+20
j com.nbarraille.jspotify.main.Test.main([Ljava/lang/String;)V+273
v ~StubRoutines::call_stub
--------------- P R O C E S S ---------------
Java Threads: ( => current thread )
0x0182fc00 JavaThread "Low Memory Detector" daemon [_thread_blocked, id=4664, stack(0x04170000,0x041c0000)]
0x0182ac00 JavaThread "C1 CompilerThread0" daemon [_thread_blocked, id=1728, stack(0x01b20000,0x01b70000)]
0x01829800 JavaThread "Attach Listener" daemon [_thread_blocked, id=112, stack(0x04020000,0x04070000)]
0x01826400 JavaThread "Signal Dispatcher" daemon [_thread_blocked, id=5836, stack(0x03ea0000,0x03ef0000)]
0x01819800 JavaThread "Finalizer" daemon [_thread_blocked, id=4724, stack(0x03f80000,0x03fd0000)]
0x01817800 JavaThread "Reference Handler" daemon [_thread_blocked, id=3940, stack(0x01ad0000,0x01b20000)]
=>0x01b79400 JavaThread "main" [_thread_in_native, id=1344, stack(0x00340000,0x00390000)]
Other Threads:
0x01816400 VMThread [stack: 0x01a30000,0x01a80000] [id=3876]
0x01843000 WatcherThread [stack: 0x040d0000,0x04120000] [id=4636]
VM state:not at safepoint (normal execution)
VM Mutex/Monitor currently owned by a thread: None
Heap
def new generation total 4928K, used 3630K [0x23450000, 0x239a0000, 0x289a0000)
eden space 4416K, 82% used [0x23450000, 0x237db858, 0x238a0000)
from space 512K, 0% used [0x238a0000, 0x238a0000, 0x23920000)
to space 512K, 0% used [0x23920000, 0x23920000, 0x239a0000)
tenured generation total 10944K, used 0K [0x289a0000, 0x29450000, 0x33450000)
the space 10944K, 0% used [0x289a0000, 0x289a0000, 0x289a0200, 0x29450000)
compacting perm gen total 12288K, used 860K [0x33450000, 0x34050000, 0x37450000)
the space 12288K, 7% used [0x33450000, 0x33527190, 0x33527200, 0x34050000)
ro space 10240K, 43% used [0x37450000, 0x3789ce40, 0x3789d000, 0x37e50000)
rw space 12288K, 53% used [0x37e50000, 0x384c2710, 0x384c2800, 0x38a50000)
Code Cache [0x01e90000, 0x01f20000, 0x03e90000)
total_blobs=234 nmethods=82 adapters=88 free_code_cache=32972224 largest_free_block=0
Dynamic libraries:
0x00880000 - 0x008b0000 C:\Program Files\Java\jdk1.7.0\bin\javaw.exe
0x778f0000 - 0x77a2d000 C:\Windows\SYSTEM32\ntdll.dll
0x77070000 - 0x77144000 C:\Windows\system32\kernel32.dll
0x75cf0000 - 0x75d3a000 C:\Windows\system32\KERNELBASE.dll
0x60000000 - 0x60041000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\midas32.dll
0x61000000 - 0x61028000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_base.m32
0x67000000 - 0x67048000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_nt.m32
0x64000000 - 0x64021000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_registry.m32
0x62000000 - 0x6202d000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_extra.m32
0x65000000 - 0x6501a000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_net.m32
0x63000000 - 0x630a6000 C:\Program Files\BitDefender\BitDefender 2011\Active Virus Control\Midas_00078_002\plugin_fragments.m32
0x75e10000 - 0x75eb0000 C:\Windows\system32\ADVAPI32.dll
0x775c0000 - 0x7766c000 C:\Windows\system32\msvcrt.dll
0x75d50000 - 0x75d69000 C:\Windows\SYSTEM32\sechost.dll
0x77670000 - 0x77711000 C:\Windows\system32\RPCRT4.dll
0x76f00000 - 0x76fc9000 C:\Windows\system32\USER32.dll
0x77a50000 - 0x77a9e000 C:\Windows\system32\GDI32.dll
0x77a30000 - 0x77a3a000 C:\Windows\system32\LPK.dll
0x75d70000 - 0x75e0d000 C:\Windows\system32\USP10.dll
0x74830000 - 0x749ce000 C:\Windows\WinSxS\x86_microsoft.windows.common-controls_6595b64144ccf1df_6.0.7600.16661_none_420fe3fa2b8113bd\COMCTL32.dll
0x772f0000 - 0x77347000 C:\Windows\system32\SHLWAPI.dll
0x775a0000 - 0x775bf000 C:\Windows\system32\IMM32.DLL
0x75eb0000 - 0x75f7c000 C:\Windows\system32\MSCTF.dll
0x72740000 - 0x727fe000 C:\Program Files\Java\jdk1.7.0\jre\bin\msvcr100.dll
0x01b80000 - 0x01e89000 C:\Program Files\Java\jdk1.7.0\jre\bin\client\jvm.dll
0x746c0000 - 0x746f2000 C:\Windows\system32\WINMM.dll
0x73920000 - 0x7392c000 C:\Program Files\Java\jdk1.7.0\jre\bin\verify.dll
0x73330000 - 0x73350000 C:\Program Files\Java\jdk1.7.0\jre\bin\java.dll
0x75d40000 - 0x75d45000 C:\Windows\system32\PSAPI.DLL
0x733a0000 - 0x733b3000 C:\Program Files\Java\jdk1.7.0\jre\bin\zip.dll
0x10000000 - 0x10259000 C:\Windows\System32\libspotify.dll
0x77150000 - 0x77185000 C:\Windows\system32\WS2_32.dll
0x77a40000 - 0x77a46000 C:\Windows\system32\NSI.dll
0x75ba0000 - 0x75cbc000 C:\Windows\system32\CRYPT32.dll
0x75ab0000 - 0x75abc000 C:\Windows\system32\MSASN1.dll
0x74ee0000 - 0x74f38000 C:\Windows\system32\WINHTTP.dll
0x74e90000 - 0x74edf000 C:\Windows\system32\webio.dll
0x754c0000 - 0x754d6000 C:\Windows\system32\CRYPTSP.dll
0x75260000 - 0x7529b000 C:\Windows\system32\rsaenh.dll
0x750a0000 - 0x750b7000 C:\Windows\system32\USERENV.dll
0x75a40000 - 0x75a4b000 C:\Windows\system32\profapi.dll
0x75a30000 - 0x75a3c000 C:\Windows\system32\CRYPTBASE.dll
0x728a0000 - 0x728b6000 C:\Program Files\Java\jdk1.7.0\jre\bin\net.dll
0x75480000 - 0x754bc000 C:\Windows\system32\mswsock.dll
0x75470000 - 0x75476000 C:\Windows\System32\wship6.dll
0x73950000 - 0x73960000 C:\Windows\system32\NLAapi.dll
0x75340000 - 0x75384000 C:\Windows\system32\DNSAPI.dll
0x71030000 - 0x71038000 C:\Windows\System32\winrnr.dll
0x71020000 - 0x71030000 C:\Windows\system32\napinsp.dll
0x71000000 - 0x71012000 C:\Windows\system32\pnrpnsp.dll
0x74fd0000 - 0x74fd5000 C:\Windows\System32\wshtcpip.dll
0x74d30000 - 0x74d4c000 C:\Windows\system32\IPHLPAPI.DLL
0x74d20000 - 0x74d27000 C:\Windows\system32\WINNSI.DLL
0x70c60000 - 0x70c66000 C:\Windows\system32\rasadhlp.dll
0x71ba0000 - 0x71bd8000 C:\Windows\System32\fwpuclnt.dll
0x73930000 - 0x7393f000 C:\Program Files\Java\jdk1.7.0\jre\bin\nio.dll
0x04990000 - 0x049e5000 C:\Users\nbarraille\AppData\Local\Temp\jna3666290841889849729.dll
VM Arguments:
jvm_args: -Djava.library.path=C:\Windows\System32 -Dfile.encoding=Cp1252
java_command: com.nbarraille.jspotify.main.Test
Launcher Type: SUN_STANDARD
Environment Variables:
PATH=C:/Program Files/Java/jdk1.7.0/bin/../jre/bin/client;C:/Program Files/Java/jdk1.7.0/bin/../jre/bin;C:/Program Files/Java/jdk1.7.0/bin/../jre/lib/i386;C:\Windows\System32
USERNAME=nbarraille
OS=Windows_NT
PROCESSOR_IDENTIFIER=x86 Family 6 Model 23 Stepping 10, GenuineIntel
--------------- S Y S T E M ---------------
OS: Windows 7 Build 7600
CPU:total 2 (2 cores per cpu, 1 threads per core) family 6 model 23 stepping 10, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1
Memory: 4k page, physical 3624108k(885020k free), swap 7246452k(3637664k free)
vm_info: Java HotSpot(TM) Client VM (21.0-b01) for windows-x86 JRE (1.7.0-ea-b129), built on Feb 10 2011 07:43:39 by "java_re" with unknown MS VC++:1600
time: Mon Mar 07 14:25:08 2011
elapsed time: 0 seconds
EDIT:
*Code to test the API in C*
#include "api.h"
/* --- Data --- */
const uint8_t g_appkey[] = {/*My appkey*/};
/* --------------------------- SESSION CALLBACKS ------------------------- */
static void logged_in(sp_session *sess, sp_error error){
printf("logged_in() called: \n");
}
static void log_message(sp_session *sess, const char *data){
printf("log_message() called %s : \n", data);
}
static void notify_main_thread(sp_session *sess){
printf("notify_main_thread() called \n");
}
static sp_session_callbacks session_callbacks = {
//.logged_in = (void*)&logged_in,
//.notify_main_thread = (void*)¬ify_main_thread,
//.log_message = (void*)&log_message,
};
static sp_session_config spconfig = {
.api_version = 7,
.cache_location = "tmp",
.settings_location = "tmp",
.application_key = g_appkey,
.application_key_size = sizeof(g_appkey),
.user_agent = "jspotify",
.callbacks = &session_callbacks,
.userdata = NULL
};
int main(int argc, char **argv)
{
sp_session *sp;
const char *username = "foo";
const char *password = "bar";
spconfig.application_key_size = sizeof(g_appkey);
printf("Creating session \n");
sp_error err = sp_session_create(&spconfig, &sp);
if(err != 0){
printf("Error occured: %d \n", err);
return 0;
}
printf("Login\n");
sp_session_login(sp, username, password);
Sleep(10000);
return 0;
}
When I run it like this (without callbacks), the output is:
Creating session
Login
And when I register the callbacks (uncomment the lines), it doesn't even print anything!
It looks like it doesn't print anything when a callback is called, because if I comment the sp_session_login line, only the declaration of notify_main_thread (which is the only one printed) will prevent the program from printing...
When you have a C structure like:
struct Foo {
Bar* bar
}
i.e. one which contains a pointer to another structure, your JNA implementation of Bar (class Bar extends Structure) must also implement the Structure.ByReference interface -- otherwise JNA will think that struct Foo contains an instance of struct Bar instead of a pointer to a struct Bar, and an illegal memory access will result as the C code interprets a value in the Bar instance as a pointer.
You need to add implements Structure.ByReference to the sp_session_callbacks class.
Thanks for inspiring me to look at JNA -- it's pretty cool!
Output of this code is:
sp_session_create returned 0
sp_session_login returned 0
log_message() called:14:16:53.825 I [ap:1388] Connecting to AP ap.spotify.com:4070
log_message() called:14:16:54.061 I [ap:938] Connected to AP: 193.182.8.11:4070
log_message() called:14:16:54.765 E [ap:3396] Connection error: 401
Process finished with exit code 0
import com.sun.jna.*;
import com.sun.jna.ptr.PointerByReference;
import java.sql.Connection;
public class JNATest {
// static {
// System.loadLibrary("libspotify");
// }
public interface JLibspotify extends Library {
int sp_session_create(sp_session_config config, PointerByReference sess);
int sp_session_login(sp_session session, String username, String password);
// All the other methods defined by the API
}
public static class sp_session extends PointerType {
public sp_session(Pointer address) {
super(address);
}
public sp_session() {
super();
}
}
public static class sp_session_config extends Structure {
public int api_version = 7; // The version of the Spotify API your application is compiled with.
public String cache_location = ".";
public String settings_location = ".";
public Pointer application_key; // Your application key.
public int application_key_size; // The size of the application key in bytes
public String user_agent = "jspotify";
public sp_session_callbacks callbacks; // Delivery callbacks for session events. NULL if not interested in any callbacks
public Pointer userdata; // User supplied data for your application
public boolean compress_playlists;
public boolean dont_save_metadata_for_playlists;
public boolean initially_unload_playlists;
}
public interface LoggedIn extends Callback {
public void logged_in(sp_session session, int error);
}
public interface LoggedOut extends Callback {
public void logged_out(sp_session session, int error);
}
public interface ConnectionError extends Callback {
public void connection_error(sp_session session, int error);
}
public static class sp_session_callbacks extends Structure implements Structure.ByReference{
public LoggedIn logged_in; // Called when login has been processed and was successful
public LoggedOut logged_out; // Called when logout has been processded. Either called explicitly if you initialize a logout operation, or implicitly if there is a permanent connection error.
public Callback metadata_updated; // Called whenever metadata has been updated. If you have metadata cached outside of libspotify, you should purge your caches and fetch new versions.
public ConnectionError connection_error; // Called when there is a connection error, and the library has problems reconnecting to the Spotify service. Could be called multiple times (as long as the problem is present)
public Callback message_to_user; // Called when the acces point wants to display a message to the user. In the desktop client, these are shown in a blueish toolbar just below the search box.
public Callback notify_main_thread; // Called when processing needs to take place on the main thread. You need to call sp_session_process_events() in the main thread to get libspotify to do more work. Failure to do so may cause request timeouts, or a lost connections.
public Callback music_delivery; // Called when there is decompressed audio data available.
public Callback play_token_lost; // Music has been paused because only one account may play music at the same time.
public Callback log_message; // Logging callback
public Callback end_of_track; // End of track. Called when the currently played track has reached its end.
public Callback streaming_error; // Streaming error. Called when streaming cannot start or continue.
public Callback userinfo_updated; // Called after user info (anything related to sp_user objects) have been updated.
public Callback start_playback; // Called when audio playback should start. For this to work correctly the application must also implement get_audio_buffer_stats(). This function is called from an internal session thread - you need to have proper synchronization. This function must never block.
public Callback stop_playback; // Called when audio playback should stop. For this to work correctly the application must also implement get_audio_buffer_stats(). This function is called from an internal session thread - you need to have proper synchronization. This function must never block.
public Callback get_audio_buffer_stats; // Called to query application about its audio buffer. This function is called from an internal session thread - you need to have proper synchronization! This function must never block.
}
private static final char[] APP_KEY ={/* Appkey here**/;
public static void main(String[] args) throws InterruptedException {
JLibspotify lib = (JLibspotify) Native.loadLibrary("spotify", JLibspotify.class);
sp_session_config cfg = new sp_session_config();
Pointer ptr = new Memory(APP_KEY.length);
ptr.write(0, toBytes(APP_KEY), 0, APP_KEY.length);
cfg.application_key = ptr;
cfg.application_key_size = APP_KEY.length;
sp_session_callbacks sessCallbacks = new sp_session_callbacks();
LoggedIn loggedInCallback = new LoggedIn() {
public void logged_in(sp_session session, int error) {
System.out.println("logged_in() called");
}
};
ConnectionError connectionErrorCallback = new ConnectionError() {
public void connection_error(sp_session session, int error) {
System.out.println("connection_error() called");
}
};
LoggedOut loggedOutCallback = new LoggedOut() {
public void logged_out(sp_session session, int error) {
System.out.println("logged_out() called");
}
};
sessCallbacks.logged_in = loggedInCallback;
sessCallbacks.connection_error = connectionErrorCallback;
sessCallbacks.logged_out = loggedOutCallback;
sessCallbacks.log_message = new Callback() {
public void callback(sp_session session, String message) {
System.out.println("log_message() called:" + message);
}
};
cfg.callbacks = sessCallbacks;
PointerByReference sessionPbr = new PointerByReference();
int error_id = lib.sp_session_create(cfg, sessionPbr); // CRASHES HERE
System.out.println("sp_session_create returned " + error_id);
//
sp_session mySession = new sp_session(sessionPbr.getValue());
error_id = lib.sp_session_login(mySession, "foo", "bar");
System.out.println("sp_session_login returned " + error_id);
Thread.sleep(1000);
}
public static byte[] toBytes(char[] key){
byte[] b = new byte[key.length];
for(int i =0; i < key.length; i++){
if(key[i] > 127){
b[i] = (byte)(key[i] - 256);
}else{
b[i] = (byte)key[i];
}
}
return b;
}
}
Here's a C program which does the same thing (with fewer callbacks -- you'll need to add more). It's for OS X so you may need to change the #include. As I can't get spotify in Australia I can't test it to see whether a successful login hits a callback, but the logging callback works.
#include <stdio.h>
#include <libspotify/api.h>
void SP_CALLCONV log_message(sp_session *session, const char *data) {
fprintf(stderr,"log_message: %s\n", data);
fflush(stderr);
}
void SP_CALLCONV connection_error(sp_session *session, sp_error error) {
fprintf(stderr,"connection_error: %d\n", error);
fflush(stderr);
}
int main(int argc, char** argv) {
static byte APP_KEY[] = {
/*the API key */};
static sp_session_callbacks callbacks;
callbacks.log_message = log_message;
callbacks.connection_error = connection_error;
static sp_session_config cfg;
cfg.callbacks = &callbacks;
cfg.api_version = 7;
cfg.cache_location = ".";
cfg.settings_location = ".";
cfg.user_agent = "jspotify";
cfg.application_key = APP_KEY;
cfg.application_key_size = sizeof(APP_KEY);
sp_session* mySession;
int code = sp_session_create(&cfg, &mySession);
printf("sp_session_create returned %d\n", code);
sp_session_login(mySession, "foo", "bar");
printf("sp_session_login returned %d\n", code);
sleep(10);
}
If the C program calls callbacks which the Java version doesn't, then perhaps there's something wrong with the use of jna -- if not, perhaps there's something more to understand about spotify and when it calls callbacks. I agree that the docs seem to say that a successful login will call a callback, but perhaps they're out of date?