org.tanukisoftware.wrapper

Class WrapperManager

Implemented Interfaces:
Runnable

public final class WrapperManager
extends java.lang.Object
implements Runnable

Handles all communication with the native portion of the Wrapper code. The native wrapper code will launch Java in a separate process and set up a server socket which the Java code is expected to open a socket to on startup. When the server socket is created, a port will be chosen depending on what is available to the system. This port will then be passed to the Java process as property named "wrapper.port". For security reasons, the native code will only allow connections from localhost and will expect to receive the key specified in a property named "wrapper.key". This class is implemented as a singleton class. Generate JNI Headers with the following command in the build/classes directory: javah -jni -classpath ./ org.tanukisoftware.wrapper.WrapperManager
Version:
$Revision: 1.39 $
Author:
Leif Mortenson

Field Summary

static int
WRAPPER_CTRL_CLOSE_EVENT
static int
WRAPPER_CTRL_C_EVENT
static int
WRAPPER_CTRL_LOGOFF_EVENT
static int
WRAPPER_CTRL_SHUTDOWN_EVENT
static int
WRAPPER_LOG_LEVEL_ADVICE
Log message at advice log level.
static int
WRAPPER_LOG_LEVEL_DEBUG
Log message at debug log level.
static int
WRAPPER_LOG_LEVEL_ERROR
Log message at error log level.
static int
WRAPPER_LOG_LEVEL_FATAL
Log message at fatal log level.
static int
WRAPPER_LOG_LEVEL_INFO
Log message at info log level.
static int
WRAPPER_LOG_LEVEL_STATUS
Log message at status log level.
static int
WRAPPER_LOG_LEVEL_WARN
Log message at warn log level.

Method Summary

static void
accessViolation()
(Testing Method) Cause an access violation within the Java code.
static void
accessViolationNative()
(Testing Method) Cause an access violation within native JNI code.
static void
appearHung()
(Testing Method) Causes the WrapperManager to go into a state which makes the JVM appear to be hung when viewed from the native Wrapper code.
static String
getBuildTime()
Obtain the build time of Wrapper.
static WrapperUser
getInteractiveUser(boolean groups)
Returns a WrapperUser object which describes the interactive user whose desktop is being interacted with.
static int
getJVMId()
Returns the Id of the current JVM.
protected static int
getNonDaemonThreadCount()
Returns a count of all non-daemon threads in the JVM, starting with the top thread group.
static WrapperUser
getUser(boolean groups)
Returns a WrapperUser object which describes the user under which the Wrapper is currently running.
static String
getVersion()
Obtain the current version of Wrapper.
static boolean
hasShutdownHookBeenTriggered()
Returns true if the ShutdownHook for the JVM has already been triggered.
static boolean
isControlledByNativeWrapper()
Returns true if the JVM was launched by the Wrapper application.
static boolean
isDebugEnabled()
Returns true if the wrapper.debug property, or any of the logging channels are set to DEBUG in the wrapper configuration file.
static boolean
isLaunchedAsService()
Returns true if the Wrapper was launched as an NT service on Windows or as a daemon process on UNIX platforms.
static void
log(int logLevel, String message)
Requests that the Wrapper log a message at the specified log level.
static void
requestThreadDump()
Requests that the current JVM process request a thread dump.
static void
restart()
Tells the native wrapper that the JVM wants to restart, then informs all listeners that the JVM is about to shutdown before killing the JVM.
void
run()
static void
setConsoleTitle(String title)
Sets the title of the console in which the Wrapper is running.
static void
signalStarting(int waitHint)
Signal the native wrapper that the startup is progressing but that more time is needed.
static void
signalStopped(int exitCode)
This method should not normally be called by user code as it is called from within the stop and restart methods.
static void
signalStopping(int waitHint)
Signal the native wrapper that the shutdown is progressing but that more time is needed.
static void
start(WrapperListener listener, String[] args)
Start the Java side of the Wrapper code running.
static void
stop(int exitCode)
Tells the native wrapper that the JVM wants to shut down, then informs all listeners that the JVM is about to shutdown before killing the JVM.
static void
stopImmediate(int exitCode)
Tells the native wrapper that the JVM wants to shut down and then promptly halts.

Field Details

WRAPPER_CTRL_CLOSE_EVENT

public static final int WRAPPER_CTRL_CLOSE_EVENT
Field Value:
201

WRAPPER_CTRL_C_EVENT

public static final int WRAPPER_CTRL_C_EVENT
Field Value:
200

WRAPPER_CTRL_LOGOFF_EVENT

public static final int WRAPPER_CTRL_LOGOFF_EVENT
Field Value:
202

WRAPPER_CTRL_SHUTDOWN_EVENT

public static final int WRAPPER_CTRL_SHUTDOWN_EVENT
Field Value:
203

WRAPPER_LOG_LEVEL_ADVICE

public static final int WRAPPER_LOG_LEVEL_ADVICE
Log message at advice log level.
Field Value:
7

WRAPPER_LOG_LEVEL_DEBUG

public static final int WRAPPER_LOG_LEVEL_DEBUG
Log message at debug log level.
Field Value:
1

WRAPPER_LOG_LEVEL_ERROR

public static final int WRAPPER_LOG_LEVEL_ERROR
Log message at error log level.
Field Value:
5

WRAPPER_LOG_LEVEL_FATAL

public static final int WRAPPER_LOG_LEVEL_FATAL
Log message at fatal log level.
Field Value:
6

WRAPPER_LOG_LEVEL_INFO

public static final int WRAPPER_LOG_LEVEL_INFO
Log message at info log level.
Field Value:
2

WRAPPER_LOG_LEVEL_STATUS

public static final int WRAPPER_LOG_LEVEL_STATUS
Log message at status log level.
Field Value:
3

WRAPPER_LOG_LEVEL_WARN

public static final int WRAPPER_LOG_LEVEL_WARN
Log message at warn log level.
Field Value:
4

Method Details

accessViolation

public static void accessViolation()
(Testing Method) Cause an access violation within the Java code. Useful for testing the Wrapper functions. This currently only crashes Sun JVMs and takes advantage of Bug #4369043 which does not exist in newer JVMs. Use of the accessViolationNative() method is preferred.

accessViolationNative

public static void accessViolationNative()
(Testing Method) Cause an access violation within native JNI code. Useful for testing the Wrapper functions. This currently causes the access violation by attempting to write to a null pointer.

appearHung

public static void appearHung()
(Testing Method) Causes the WrapperManager to go into a state which makes the JVM appear to be hung when viewed from the native Wrapper code. Does not have any effect when the JVM is not being controlled from the native Wrapper. Useful for testing the Wrapper functions.

getBuildTime

public static String getBuildTime()
Obtain the build time of Wrapper.
Returns:
The time that the Wrapper was built.

getInteractiveUser

public static WrapperUser getInteractiveUser(boolean groups)
Returns a WrapperUser object which describes the interactive user whose desktop is being interacted with. When a service running on a Windows platform has its interactive flag set, this method will return the user who is currently logged in. Additional platform specific information can be obtained by casting the object to a platform specific subclass. WrapperWin32User, for example.

If a user is not currently logged on then this method will return null. User code can repeatedly call this method to detect when a user has logged in. To detect when a user has logged out, there are two options. 1) The user code can continue to call this method until it returns null. 2) Or if the WrapperListener method is being implemented, the WrapperListener.controlEvent method will receive a WRAPPER_CTRL_LOGOFF_EVENT event when the user logs out.

On XP systems, it is possible to switch to another account rather than actually logging out. In such a case, the interactive user will be the first user that logged in. This will also be the only user with which the service will interact. If other users are logged in when the interactive user logs out, the service will not automatically switch to another logged in user. Rather, the next user to log in will become the new user which the service will interact with.

This method will always return NULL on versions of NT prior to Windows 2000. This can not be helped as some required functions were not added to the windows API until NT version 5.0, also known as Windows 2000.

Parameters:
groups - True if the user's groups should be returned as well. Requesting the groups that a user belongs to increases the CPU load required to complete the call.
Returns:
The current interactive user, or null.

getJVMId

public static int getJVMId()
Returns the Id of the current JVM. JVM Ids increment from 1 each time the wrapper restarts a new one.
Returns:
The Id of the current JVM.

getNonDaemonThreadCount

protected static int getNonDaemonThreadCount()
Returns a count of all non-daemon threads in the JVM, starting with the top thread group.
Returns:
Number of non-daemon threads.

getUser

public static WrapperUser getUser(boolean groups)
Returns a WrapperUser object which describes the user under which the Wrapper is currently running. Additional platform specific information can be obtained by casting the object to a platform specific subclass. WrapperWin32User, for example.
Parameters:
groups - True if the user's groups should be returned as well. Requesting the groups that a user belongs to increases the CPU load required to complete the call.
Returns:
An object describing the current user.

getVersion

public static String getVersion()
Obtain the current version of Wrapper.
Returns:
The version of the Wrapper.

hasShutdownHookBeenTriggered

public static boolean hasShutdownHookBeenTriggered()
Returns true if the ShutdownHook for the JVM has already been triggered. Some code needs to know whether or not the system is shutting down.
Returns:
True if the ShutdownHook for the JVM has already been triggered.

isControlledByNativeWrapper

public static boolean isControlledByNativeWrapper()
Returns true if the JVM was launched by the Wrapper application. False if the JVM was launched manually without the Wrapper controlling it.
Returns:
True if the current JVM was launched by the Wrapper.

isDebugEnabled

public static boolean isDebugEnabled()
Returns true if the wrapper.debug property, or any of the logging channels are set to DEBUG in the wrapper configuration file. Useful for deciding whether or not to output certain information to the console.
Returns:
True if the Wrapper is logging any Debug level output.

isLaunchedAsService

public static boolean isLaunchedAsService()
Returns true if the Wrapper was launched as an NT service on Windows or as a daemon process on UNIX platforms. False if launched as a console. This can be useful if you wish to display a user interface when in Console mode. On UNIX platforms, this is not as useful because an X display may not be visible even if launched in a console.
Returns:
True if the Wrapper is running as an NT service or daemon process.

log

public static void log(int logLevel,
                       String message)
Requests that the Wrapper log a message at the specified log level. If the JVM is not being managed by the Wrapper then calls to this method will be ignored. This method has been optimized to ignore messages at a log level which will not be logged given the current log levels of the Wrapper.

Log messages will currently by trimmed by the Wrapper at 4k (4096 bytes).

Because of differences in the way console output is collected and messages logged via this method, it is expected that interspersed console and log messages will not be in the correct order in the resulting log file.

This method was added to allow simple logging to the wrapper.log file. This is not meant to be a full featured log file and should not be used as such. Please look into a logging package for most application logging.

Parameters:
logLevel - The level to log the message at can be one of WRAPPER_LOG_LEVEL_DEBUG, WRAPPER_LOG_LEVEL_INFO, WRAPPER_LOG_LEVEL_STATUS, WRAPPER_LOG_LEVEL_WARN, WRAPPER_LOG_LEVEL_ERROR, or WRAPPER_LOG_LEVEL_FATAL.
message - The message to be logged.

requestThreadDump

public static void requestThreadDump()
Requests that the current JVM process request a thread dump. This is the same as pressing CTRL-BREAK (under Windows) or CTRL-\ (under Unix) in the the console in which Java is running. This method does nothing if the native library is not loaded.

restart

public static void restart()
Tells the native wrapper that the JVM wants to restart, then informs all listeners that the JVM is about to shutdown before killing the JVM.

run

public void run()

setConsoleTitle

public static void setConsoleTitle(String title)
Sets the title of the console in which the Wrapper is running. This is currently only supported on Windows platforms.

As an alternative, it is also possible to set the console title from within the wrapper.conf file using the wrapper.console.title property.

Parameters:
title - The new title. The specified string will be encoded to a byte array using the default encoding for the current platform.

signalStarting

public static void signalStarting(int waitHint)
Signal the native wrapper that the startup is progressing but that more time is needed. The Wrapper will extend the startup timeout by the specified time.
Parameters:
waitHint - Additional time in milliseconds.

signalStopped

public static void signalStopped(int exitCode)
This method should not normally be called by user code as it is called from within the stop and restart methods. However certain applications which stop the JVM may need to call this method to let the wrapper code know that the shutdown was intentional.

signalStopping

public static void signalStopping(int waitHint)
Signal the native wrapper that the shutdown is progressing but that more time is needed. The Wrapper will extend the stop timeout by the specified time.
Parameters:
waitHint - Additional time in milliseconds.

start

public static void start(WrapperListener listener,
                         String[] args)
Start the Java side of the Wrapper code running. This will make it possible for the native side of the Wrapper to detect that the Java Wrapper is up and running.

stop

public static void stop(int exitCode)
Tells the native wrapper that the JVM wants to shut down, then informs all listeners that the JVM is about to shutdown before killing the JVM.
Parameters:
exitCode - The exit code that the Wrapper will return when it exits.

stopImmediate

public static void stopImmediate(int exitCode)
Tells the native wrapper that the JVM wants to shut down and then promptly halts. Be careful when using this method as an application will not be given a chance to shutdown cleanly.
Parameters:
exitCode - The exit code that the Wrapper will return when it exits.

Copyright 1999, 2003 TanukiSoftware.org. All Rights Reserved.