org.jppf.management.diagnostics

Interface DiagnosticsMBean

All Known Implementing Classes:

DriverDiagnosticsMBeanStaticProxy, NodeDiagnosticsMBeanStaticProxy

public interface DiagnosticsMBean

Interface for the diagnostics MBean.

Field Summary

Fields

Modifier and Type	Field and Description
static String	MBEAN_NAME_DRIVER The name of this MBean in a driver.
static String	MBEAN_NAME_NODE The name of this MBean in a node.

Method Summary

Methods

Modifier and Type	Method and Description
Double	cpuLoad() Get an approximation of the current CPU load.
void	gc() Perform a garbage collection.
Boolean	hasDeadlock() Determine whether a deadlock is detected in the JVM.
HealthSnapshot	healthSnapshot() Get a summarized snapshot of the JVM health.
String	healthSnapshotAsString() Get a a string representation of a JVM health snapshot.
String	heapDump() Trigger a heap dump of the JVM.
MemoryInformation	memoryInformation() Get the diagnostics info for the whole JVM.
ThreadDump	threadDump() Get a full thread dump, including detection of deadlocks.
String[]	threadNames() Get the names of all live threads in the current JVM.

Field Detail

MBEAN_NAME_DRIVER

static final String MBEAN_NAME_DRIVER

The name of this MBean in a driver.

See Also:

Constant Field Values

MBEAN_NAME_NODE

static final String MBEAN_NAME_NODE

The name of this MBean in a node.

See Also:

Constant Field Values

Method Detail

memoryInformation

MemoryInformation memoryInformation()
                                    throws Exception

Get the diagnostics info for the whole JVM.

Returns:

a MemoryInformation instance.

Throws:

Exception - if any error occurs.

threadNames

String[] threadNames()
                     throws Exception

Get the names of all live threads in the current JVM.

Returns:

an arrray of thread names as strings.

Throws:

Exception - if any error occurs.

gc

void gc()
        throws Exception

Perform a garbage collection. This method calls System.gc().

Throws:

Exception - if any error occurs.

threadDump

ThreadDump threadDump()
                      throws Exception

Get a full thread dump, including detection of deadlocks.

Returns:

a ThreadDump instance.

Throws:

Exception - if any error occurs.

hasDeadlock

Boolean hasDeadlock()
                    throws Exception

Determine whether a deadlock is detected in the JVM.

Returns:

true if a deadlock is detected, false otherwise.

Throws:

Exception - if any error occurs.

healthSnapshot

HealthSnapshot healthSnapshot()
                              throws Exception

Get a summarized snapshot of the JVM health.

Returns:

a HealthSnapshot instance.

Throws:

Exception - if any error occurs.

healthSnapshotAsString

String healthSnapshotAsString()
                              throws Exception

Get a a string representation of a JVM health snapshot. The returned string contains a set of key / value pairs separated by new lines. As such, it can be loaded directly into a Properties or TypedProperties object via their load(Reader) method, using a StringReader.

Returns:

a Properties-compatible string representation of a JVM health snapshot.

Throws:

Exception - if any error occurs.

heapDump

String heapDump()
                throws Exception

Trigger a heap dump of the JVM. This will not work with all JVM implementations. It should work with Oracle standard and JRockit JVMs, along with IBM JVM.

Returns:

a message describing the outcome.

Throws:

Exception - if any error occurs.

cpuLoad

Double cpuLoad()

Get an approximation of the current CPU load. The computed value is equal to sumi(thread_used_cpui) / interval, for all the live threads of the JVM at the time of the computation. Thus, errors may occur, since many threads may have been created then died between two computations. However, in most cases this is a reasonable approximation, whose computation does not tax the CPU too heavily.

Returns:

the cpu load as a double value in the range [0, 1] (ratio of totalCpuTime / computationInterval), or -1d if CPU time measurement is not available for the JVM.