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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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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,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package sun.jvmstat.perfdata.monitor.v1_0;
import sun.jvmstat.monitor.*;
import sun.jvmstat.perfdata.monitor.*;
import java.nio.*;
/**
* Class representing the 1.0 version of the HotSpot PerfData instrumentation
* buffer header.
* <p>
* The PerfDataBufferPrologue2_0 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
* } PerfDataPrologue
* </pre>
*
* @author Brian Doherty
* @since 1.5
*/
public class PerfDataBufferPrologue extends AbstractPerfDataBufferPrologue {
private static final int SUPPORTED_MAJOR_VERSION = 1;
private static final int SUPPORTED_MINOR_VERSION = 0;
/*
* the following constants must match the field offsets and sizes
* in the PerfDataPrologue structure in perfMemory.hpp
*/
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_SIZE=24; // sizeof(struct PerfDataProlog)
// counter names for prologue psuedo counters
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";
/**
* 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() == 1) && (getMinorVersion() == 0));
}
/**
* {@inheritDoc}
*/
public boolean supportsAccessible() {
return false;
}
/**
* {@inheritDoc}
*/
public boolean isAccessible() {
return true;
}
/**
* 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();
}
/**
* {@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()
*/
public 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()
*/
public 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()
*/
public IntBuffer overflowBuffer() {
byteBuffer.position(PERFDATA_PROLOG_OVERFLOW_OFFSET);
IntBuffer ib = byteBuffer.asIntBuffer();
ib.limit(1);
return ib;
}
/**
* Return an 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()
*/
public LongBuffer modificationTimeStampBuffer() {
byteBuffer.position(PERFDATA_PROLOG_MODTIMESTAMP_OFFSET);
LongBuffer lb = byteBuffer.asLongBuffer();
lb.limit(1);
return lb;
}
}