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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package sun.jvmstat.perfdata.monitor.v2_0;
import sun.jvmstat.monitor.*;
import sun.jvmstat.perfdata.monitor.*;
import java.nio.*;
/**
* Class representing the 2.0 version of the HotSpot PerfData instrumentation
* buffer header.
* <p>
* The PerfDataBufferPrologue class supports parsing of the version
* specific portions of the PerfDataPrologue C structure:
* <pre>
* typedef struct {
* ... // handled by superclass
* jint used; // number of PerfData memory bytes used
* jint overflow; // number of bytes of overflow
* jlong mod_time_stamp; // time stamp of the last structural modification
* jint entry_offset; // offset of the first PerfDataEntry
* jint num_entries; // number of allocated PerfData entries
* } PerfDataPrologue
* </pre>
*
* @author Brian Doherty
* @since 1.5
*/
public class PerfDataBufferPrologue extends AbstractPerfDataBufferPrologue {
private final static int SUPPORTED_MAJOR_VERSION = 2;
private final static int SUPPORTED_MINOR_VERSION = 0;
/*
* the following constants must match the field offsets and sizes
* in the PerfDataPrologue structure in perfMemory.hpp. offsets are
* relative to the start of the PerfDataPrologue structure.
*
* note that PERFDATA_PROLOG_ACCESSIBLE_OFFSET redefines
* PERFDATA_PROLOG_RESERVEDB1_OFFSET from AbstractPerfDataBufferPrologue.
*/
final static int PERFDATA_PROLOG_ACCESSIBLE_OFFSET=7;
final static int PERFDATA_PROLOG_ACCESSIBLE_SIZE=1; // sizeof(byte)
final static int PERFDATA_PROLOG_USED_OFFSET=8;
final static int PERFDATA_PROLOG_USED_SIZE=4; // sizeof(int)
final static int PERFDATA_PROLOG_OVERFLOW_OFFSET=12;
final static int PERFDATA_PROLOG_OVERFLOW_SIZE=4; // sizeof(int)
final static int PERFDATA_PROLOG_MODTIMESTAMP_OFFSET=16;
final static int PERFDATA_PROLOG_MODTIMESTAMP_SIZE=8; // sizeof(long)
final static int PERFDATA_PROLOG_ENTRYOFFSET_OFFSET=24;
final static int PERFDATA_PROLOG_ENTRYOFFSET_SIZE=4; // sizeof(int)
final static int PERFDATA_PROLOG_NUMENTRIES_OFFSET=28;
final static int PERFDATA_PROLOG_NUMENTRIES_SIZE=4; // sizeof(int)
final static int PERFDATA_PROLOG_SIZE=32; // sizeof(struct PerfDataProlog)
// names for counters that expose prologue fields
final static String PERFDATA_BUFFER_SIZE_NAME = "sun.perfdata.size";
final static String PERFDATA_BUFFER_USED_NAME = "sun.perfdata.used";
final static String PERFDATA_OVERFLOW_NAME = "sun.perfdata.overflow";
final static String PERFDATA_MODTIMESTAMP_NAME = "sun.perfdata.timestamp";
final static String PERFDATA_NUMENTRIES_NAME = "sun.perfdata.entries";
/**
* Create an instance of PerfDataBufferPrologue from the given
* ByteBuffer object.
*
* @param byteBuffer the buffer containing the binary header data
*/
public PerfDataBufferPrologue(ByteBuffer byteBuffer)
throws MonitorException {
super(byteBuffer);
assert ((getMajorVersion() == 2) && (getMinorVersion() == 0));
}
/**
* {@inheritDoc}
*/
public boolean supportsAccessible() {
return true;
}
/**
* {@inheritDoc}
*/
public boolean isAccessible() {
assert supportsAccessible();
byteBuffer.position(PERFDATA_PROLOG_ACCESSIBLE_OFFSET);
byte value = byteBuffer.get();
return value != 0;
}
/**
* Get the utilization of the instrumentation memory buffer.
*
* @return int - the utilization of the buffer
*/
public int getUsed() {
byteBuffer.position(PERFDATA_PROLOG_USED_OFFSET);
return byteBuffer.getInt();
}
/**
* Get the size of the instrumentation memory buffer.
*
* @return int - the size of the buffer
*/
public int getBufferSize() {
return byteBuffer.capacity();
}
/**
* Get the buffer overflow amount. This value is non-zero if the
* HotSpot JVM has overflowed the instrumentation memory buffer.
* The target JVM can be restarted with -XX:PerfDataMemSize=X to
* create a larger memory buffer.
*
* @return int - the size of the buffer
*/
public int getOverflow() {
byteBuffer.position(PERFDATA_PROLOG_OVERFLOW_OFFSET);
return byteBuffer.getInt();
}
/**
* Get the time of last modification for the instrumentation
* memory buffer. This method returns the time, as ticks since the
* start of the target JVM, of the last structural modification to
* the instrumentation buffer. Structural modifications correspond to
* the addition or deletion of instrumentation objects. Updates to
* counter values are not structural modifications.
*/
public long getModificationTimeStamp() {
byteBuffer.position(PERFDATA_PROLOG_MODTIMESTAMP_OFFSET);
return byteBuffer.getLong();
}
/**
* Get the offset of the first PerfDataEntry.
*/
public int getEntryOffset() {
byteBuffer.position(PERFDATA_PROLOG_ENTRYOFFSET_OFFSET);
return byteBuffer.getInt();
}
/**
* Get the offset of the first PerfDataEntry.
*/
public int getNumEntries() {
byteBuffer.position(PERFDATA_PROLOG_NUMENTRIES_OFFSET);
return byteBuffer.getInt();
}
/**
* {@inheritDoc}
*/
public int getSize() {
return PERFDATA_PROLOG_SIZE; // sizeof(struct PerfDataProlog)
}
/**
* Return an IntBuffer that accesses the used value. This is used
* to create a Monitor object for this value.
*
* @return IntBuffer - a ByteBuffer that accesses the used value
* in the instrumentation buffer header.
* @see #getUsed()
*/
IntBuffer usedBuffer() {
byteBuffer.position(PERFDATA_PROLOG_USED_OFFSET);
IntBuffer ib = byteBuffer.asIntBuffer();
ib.limit(1);
return ib;
}
/**
* Return an IntBuffer that accesses the size value. This is used
* to create a Monitor object for this value.
*
* @return IntBuffer - a ByteBuffer that accesses the size value
* in the instrumentation buffer header.
* @see #getBufferSize()
*/
IntBuffer sizeBuffer() {
IntBuffer ib = IntBuffer.allocate(1);
ib.put(byteBuffer.capacity());
return ib;
}
/**
* Return an IntBuffer that accesses the overflow value. This is used
* to create a Monitor object for this value.
*
* @return IntBuffer - a ByteBuffer that accesses the overflow value
* in the instrumentation buffer header.
* @see #getOverflow()
*/
IntBuffer overflowBuffer() {
byteBuffer.position(PERFDATA_PROLOG_OVERFLOW_OFFSET);
IntBuffer ib = byteBuffer.asIntBuffer();
ib.limit(1);
return ib;
}
/**
* Return a LongBuffer that accesses the modification timestamp value.
* This is used to create a Monitor object for this value.
*
* @return LongBuffer - a ByteBuffer that accesses the modification time
* stamp value in the instrumentation buffer header.
* @see #getModificationTimeStamp()
*/
LongBuffer modificationTimeStampBuffer() {
byteBuffer.position(PERFDATA_PROLOG_MODTIMESTAMP_OFFSET);
LongBuffer lb = byteBuffer.asLongBuffer();
lb.limit(1);
return lb;
}
/**
* Return an IntBuffer that accesses the number of entries value.
* This is used to create a Monitor object for this value.
*
* @return LongBuffer - a ByteBuffer that accesses the num_entries
* value in the instrumentation buffer header.
* @see #getNumEntries()
*/
IntBuffer numEntriesBuffer() {
byteBuffer.position(PERFDATA_PROLOG_NUMENTRIES_OFFSET);
IntBuffer ib = byteBuffer.asIntBuffer();
ib.limit(1);
return ib;
}
}