sun.jvmstat.perfdata.monitor

Class AbstractPerfDataBuffer

java.lang.Object

sun.jvmstat.perfdata.monitor.AbstractPerfDataBuffer

Direct Known Subclasses:

PerfDataBuffer, PerfDataBuffer, PerfDataBuffer

public abstract class AbstractPerfDataBuffer
extends Object

Abstraction for the HotSpot PerfData instrumentation buffer. This class is responsible for acquiring access to the instrumentation buffer for a target HotSpot Java Virtual Machine and providing method level access to its contents.

Since:

1.5

Author:

Brian Doherty

Field Summary

Fields

Modifier and Type	Field and Description
protected PerfDataBufferImpl	impl Reference to the concrete instance created by the createPerfDataBuffer(java.nio.ByteBuffer, int) method.

Constructor Summary

Constructors

Constructor and Description
AbstractPerfDataBuffer()

Method Summary

Modifier and Type	Method and Description
protected void	createPerfDataBuffer(ByteBuffer bb, int lvmid) Create the perfdata instrumentation buffer for the given lvmid using the given ByteBuffer object as the source of the instrumentation data.
Monitor	findByName(String name) Find a named Instrumentation object.
List<Monitor>	findByPattern(String patternString) Find all Instrumentation objects with names matching the given pattern.
ByteBuffer	getByteBuffer() Get the ByteBuffer containing the instrumentation data.
byte[]	getBytes() Get a copy of the raw instrumentation data.
int	getCapacity() Get the capacity of the instrumentation buffer.
int	getLocalVmId() Get the Local Java Virtual Machine Identifier, or lvmid for the target JVM associated with this instrumentation buffer.
MonitorStatus	getMonitorStatus() Get a list of the inserted and removed monitors since last called.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

impl

protected PerfDataBufferImpl impl

Reference to the concrete instance created by the createPerfDataBuffer(java.nio.ByteBuffer, int) method.

Constructor Detail

AbstractPerfDataBuffer

public AbstractPerfDataBuffer()

Method Detail

getLocalVmId

public int getLocalVmId()

Get the Local Java Virtual Machine Identifier, or lvmid for the target JVM associated with this instrumentation buffer.

Returns:

int - the lvmid

getBytes

public byte[] getBytes()

Get a copy of the raw instrumentation data. This method is used to get a copy of the current bytes in the instrumentation buffer. It is generally used for transporting those bytes over the network.

Returns:

byte[] - a copy of the bytes in the instrumentation buffer.

getCapacity

public int getCapacity()

Get the capacity of the instrumentation buffer.

Returns:

int - the capacity, or size, of the instrumentation buffer.

findByName

public Monitor findByName(String name)
                   throws MonitorException

Find a named Instrumentation object. This method will look for the named instrumentation object in the instrumentation exported by this Java Virtual Machine. If an instrumentation object with the given name exists, a Monitor interface to that object will be return. Otherwise, the method returns null.

Parameters:

name - the name of the Instrumentation object to find.

Returns:

Monitor - the Monitor object that can be used to monitor the the named instrumentation object, or null if the named object doesn't exist.

Throws:

MonitorException - Thrown if an error occurs while communicating with the target Java Virtual Machine.

findByPattern

public List<Monitor> findByPattern(String patternString)
                            throws MonitorException

Find all Instrumentation objects with names matching the given pattern. This method returns a List of Monitor objects such that the name of each object matches the given pattern.

Parameters:

patternString - a string containing a pattern as described in Pattern.

Returns:

List - a List of Monitor objects that can be used to monitor the instrumentation objects whose names match the given pattern. If no instrumentation objects have` names matching the given pattern, then an empty List is returned.

Throws:

MonitorException - Thrown if an error occurs while communicating with the target Java Virtual Machine.

See Also:

Pattern

getMonitorStatus

public MonitorStatus getMonitorStatus()
                               throws MonitorException

Get a list of the inserted and removed monitors since last called.

Returns:

MonitorStatus - the status of available Monitors for the target Java Virtual Machine.

Throws:

MonitorException - Thrown if communications errors occur while communicating with the target.

getByteBuffer

public ByteBuffer getByteBuffer()

Get the ByteBuffer containing the instrumentation data.

Returns:

ByteBuffer - a ByteBuffer object that refers to the instrumentation data.

createPerfDataBuffer

protected void createPerfDataBuffer(ByteBuffer bb,
                                    int lvmid)
                             throws MonitorException

Create the perfdata instrumentation buffer for the given lvmid using the given ByteBuffer object as the source of the instrumentation data. This method parses the instrumentation buffer header to determine key characteristics of the instrumentation buffer and then dynamically loads the appropriate class to handle the particular instrumentation version.

Parameters:

bb - the ByteBuffer that references the instrumentation data.

lvmid - the Local Java Virtual Machine identifier for this instrumentation buffer.

Throws:

MonitorException