PerfDataBuffer

Class Overview

The concrete implementation of version 2.0 of the HotSpot PerfData Instrumentation buffer. This class is responsible for parsing the instrumentation memory and constructing the necessary objects to represent and access the instrumentation objects contained in the memory buffer.

The structure of the 2.0 entry is defined in struct PerfDataEnry as decsribed in perfMemory.hpp. This structure looks like:

 typedef struct {
   jint entry_length;         // entry length in bytes
   jint name_offset;          // offset to entry name, relative to start
                              // of entry
   jint vector_length;        // length of the vector. If 0, then scalar.
   jbyte data_type;           // JNI field descriptor type
   jbyte flags;               // miscellaneous attribute flags
                              // 0x01 - supported
   jbyte data_units;          // unit of measure attribute
   jbyte data_variability;    // variability attribute
   jbyte data_offset;         // offset to data item, relative to start
                              // of entry.
 } PerfDataEntry;
 

Summary

[Expand] Inherited Fields

From class sun.jvmstat.perfdata.monitor.PerfDataBufferImpl protected Map aliasCache A cache of resolved monitor aliases. protected Map<String, ArrayList<String>> aliasMap A Map of monitor object names to aliases as read in from the alias map file. protected ByteBuffer buffer The buffer containing the instrumentation data. protected int lvmid The Local Java Virtual Machine Identifier for this buffer. protected Map<String, Monitor> monitors A Map of monitor objects found in the instrumentation buffer.

[Expand] Inherited Methods
From class sun.jvmstat.perfdata.monitor.PerfDataBufferImpl abstract void buildMonitorMap(Map<String, Monitor> m) build the map of Monitor objects. Monitor findByAlias(String name) Find the Monitor object for the named counter by using one of its aliases. Monitor findByName(String name) Find a named Instrumentation object. List<Monitor> findByPattern(String patternString) Find all Instrumentation objects with names matching the given pattern. 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. abstract MonitorStatus getMonitorStatus(Map<String, Monitor> m) get the list of inserted and removed monitors since last called. MonitorStatus getMonitorStatus() Get a list of the inserted and removed monitors since last called. abstract void getNewMonitors(Map<String, Monitor> m) get the new Monitor objects from the Map of Monitor objects.
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object. final void wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. final void wait(long timeout) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed.