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*
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* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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package sun.management.snmp.jvminstr;
// java imports
//
import java.io.Serializable;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
// jmx imports
//
import com.sun.jmx.snmp.SnmpOid;
import com.sun.jmx.snmp.SnmpStatusException;
// jdmk imports
//
import com.sun.jmx.snmp.agent.SnmpMib;
import com.sun.jmx.snmp.agent.SnmpStandardObjectServer;
import java.lang.management.MemoryManagerMXBean;
import java.lang.management.GarbageCollectorMXBean;
import java.lang.management.ManagementFactory;
import sun.management.snmp.jvmmib.JvmMemGCTableMeta;
import sun.management.snmp.util.SnmpCachedData;
import sun.management.snmp.util.SnmpTableCache;
import sun.management.snmp.util.SnmpTableHandler;
import sun.management.snmp.util.MibLogger;
import sun.management.snmp.util.JvmContextFactory;
The class is used for implementing the "JvmMemGCTable" table.
/**
* The class is used for implementing the "JvmMemGCTable" table.
*/
public class JvmMemGCTableMetaImpl extends JvmMemGCTableMeta {
static final long serialVersionUID = 8250461197108867607L;
This class acts as a filter over the SnmpTableHandler
used for the JvmMemoryManagerTable. It filters out
(skip) all MemoryManagerMXBean that are not instances of
GarbageCollectorMXBean so that only Garbage Collectors are
seen. This is a better solution than relying on
ManagementFactory.getGarbageCollectorMXBeans() because it makes it
possible to guarantee the consistency betwen the MemoryManager table
and the GCTable since both will be sharing the same cache.
/**
* This class acts as a filter over the SnmpTableHandler
* used for the JvmMemoryManagerTable. It filters out
* (skip) all MemoryManagerMXBean that are not instances of
* GarbageCollectorMXBean so that only Garbage Collectors are
* seen. This is a better solution than relying on
* ManagementFactory.getGarbageCollectorMXBeans() because it makes it
* possible to guarantee the consistency betwen the MemoryManager table
* and the GCTable since both will be sharing the same cache.
**/
protected static class GCTableFilter {
Returns the index that immediately follows the given
index. The returned index is strictly greater
than the given index, and is contained in the table.
If the given index is null, returns the first
index in the table.
If there are no index after the given index,
returns null.
This method is an optimization for the case where the
SnmpTableHandler is in fact an instance of SnmpCachedData.
/**
* Returns the index that immediately follows the given
* <var>index</var>. The returned index is strictly greater
* than the given <var>index</var>, and is contained in the table.
* <br>If the given <var>index</var> is null, returns the first
* index in the table.
* <br>If there are no index after the given <var>index</var>,
* returns null.
* This method is an optimization for the case where the
* SnmpTableHandler is in fact an instance of SnmpCachedData.
**/
public SnmpOid getNext(SnmpCachedData datas, SnmpOid index) {
final boolean dbg = log.isDebugOn();
// We're going to loop until we find an instance of
// GarbageCollectorMXBean. First we attempt to find
// the next element whose OID follows the given index.
// If `index' is null, the insertion point is -1
// (the next is 0 = -insertion - 1)
//
final int insertion = (index==null)?-1:datas.find(index);
if (dbg) log.debug("GCTableFilter","oid="+index+
" at insertion="+insertion);
int next;
if (insertion > -1) next = insertion+1;
else next = -insertion -1;
// Now `next' points to the element that imediately
// follows the given `index'. We're going to loop
// through the table, starting at `next' (included),
// and return the first element which is an instance
// of GarbageCollectorMXBean.
//
for (;next<datas.indexes.length;next++) {
if (dbg) log.debug("GCTableFilter","next="+next);
final Object value = datas.datas[next];
if (dbg) log.debug("GCTableFilter","value["+next+"]=" +
((MemoryManagerMXBean)value).getName());
if (value instanceof GarbageCollectorMXBean) {
// That's the next: return it.
if (dbg) log.debug("GCTableFilter",
((MemoryManagerMXBean)value).getName() +
" is a GarbageCollectorMXBean.");
return datas.indexes[next];
}
if (dbg) log.debug("GCTableFilter",
((MemoryManagerMXBean)value).getName() +
" is not a GarbageCollectorMXBean: " +
value.getClass().getName());
// skip to next index...
}
return null;
}
Returns the index that immediately follows the given
index. The returned index is strictly greater
than the given index, and is contained in the table.
If the given index is null, returns the first
index in the table.
If there are no index after the given index,
returns null.
/**
* Returns the index that immediately follows the given
* <var>index</var>. The returned index is strictly greater
* than the given <var>index</var>, and is contained in the table.
* <br>If the given <var>index</var> is null, returns the first
* index in the table.
* <br>If there are no index after the given <var>index</var>,
* returns null.
**/
public SnmpOid getNext(SnmpTableHandler handler, SnmpOid index) {
// try to call the optimized method
if (handler instanceof SnmpCachedData)
return getNext((SnmpCachedData)handler, index);
// too bad - revert to non-optimized generic algorithm
SnmpOid next = index;
do {
next = handler.getNext(next);
final Object value = handler.getData(next);
if (value instanceof GarbageCollectorMXBean)
// That's the next! return it
return next;
// skip to next index...
} while (next != null);
return null;
}
Returns the data associated with the given index.
If the given index is not found, null is returned.
Note that returning null does not necessarily means that
the index was not found.
/**
* Returns the data associated with the given index.
* If the given index is not found, null is returned.
* Note that returning null does not necessarily means that
* the index was not found.
**/
public Object getData(SnmpTableHandler handler, SnmpOid index) {
final Object value = handler.getData(index);
if (value instanceof GarbageCollectorMXBean) return value;
// Behaves as if there was nothing at this index...
//
return null;
}
Returns true if the given index is present.
/**
* Returns true if the given <var>index</var> is present.
**/
public boolean contains(SnmpTableHandler handler, SnmpOid index) {
if (handler.getData(index) instanceof GarbageCollectorMXBean)
return true;
// Behaves as if there was nothing at this index...
//
return false;
}
}
private transient JvmMemManagerTableMetaImpl managers = null;
private static GCTableFilter filter = new GCTableFilter();
Constructor for the table. Initialize metadata for "JvmMemGCTableMeta".
/**
* Constructor for the table. Initialize metadata for "JvmMemGCTableMeta".
*/
public JvmMemGCTableMetaImpl(SnmpMib myMib,
SnmpStandardObjectServer objserv) {
super(myMib,objserv);
}
// Returns a pointer to the JvmMemManager meta node - we're going
// to reuse its SnmpTableHandler by filtering out all that is
// not a GarbageCollectorMXBean.
private final JvmMemManagerTableMetaImpl getManagers(SnmpMib mib) {
if (managers == null) {
managers = (JvmMemManagerTableMetaImpl)
mib.getRegisteredTableMeta("JvmMemManagerTable");
}
return managers;
}
Returns the JvmMemManagerTable SnmpTableHandler
/**
* Returns the JvmMemManagerTable SnmpTableHandler
**/
protected SnmpTableHandler getHandler(Object userData) {
JvmMemManagerTableMetaImpl managerTable= getManagers(theMib);
return managerTable.getHandler(userData);
}
// See com.sun.jmx.snmp.agent.SnmpMibTable
protected SnmpOid getNextOid(Object userData)
throws SnmpStatusException {
// null means get the first OID.
return getNextOid(null,userData);
}
// See com.sun.jmx.snmp.agent.SnmpMibTable
protected SnmpOid getNextOid(SnmpOid oid, Object userData)
throws SnmpStatusException {
final boolean dbg = log.isDebugOn();
try {
if (dbg) log.debug("getNextOid", "previous=" + oid);
// Get the data handler.
//
SnmpTableHandler handler = getHandler(userData);
if (handler == null) {
// This should never happen.
// If we get here it's a bug.
//
if (dbg) log.debug("getNextOid", "handler is null!");
throw new
SnmpStatusException(SnmpStatusException.noSuchInstance);
}
// Get the next oid, using the GC filter.
//
final SnmpOid next = filter.getNext(handler,oid);
if (dbg) log.debug("getNextOid", "next=" + next);
// if next is null: we reached the end of the table.
//
if (next == null)
throw new
SnmpStatusException(SnmpStatusException.noSuchInstance);
return next;
} catch (RuntimeException x) {
// debug. This should never happen.
//
if (dbg) log.debug("getNextOid",x);
throw x;
}
}
// See com.sun.jmx.snmp.agent.SnmpMibTable
protected boolean contains(SnmpOid oid, Object userData) {
// Get the handler.
//
SnmpTableHandler handler = getHandler(userData);
// handler should never be null.
//
if (handler == null)
return false;
return filter.contains(handler,oid);
}
// See com.sun.jmx.snmp.agent.SnmpMibTable
public Object getEntry(SnmpOid oid)
throws SnmpStatusException {
if (oid == null)
throw new SnmpStatusException(SnmpStatusException.noSuchInstance);
// Get the request contextual cache (userData).
//
final Map<Object, Object> m = JvmContextFactory.getUserData();
// First look in the request contextual cache: maybe we've already
// created this entry...
//
// We know in the case of this table that the index is an integer,
// it is thus the first OID arc of the index OID.
//
final long index = oid.getOidArc(0);
// We're going to use this name to store/retrieve the entry in
// the request contextual cache.
//
// Revisit: Probably better programming to put all these strings
// in some interface.
//
final String entryTag = ((m==null)?null:("JvmMemGCTable.entry." +
index));
// If the entry is in the cache, simply return it.
//
if (m != null) {
final Object entry = m.get(entryTag);
if (entry != null) return entry;
}
// Entry was not in request cache. Make a new one.
//
// Get the data hanler.
//
SnmpTableHandler handler = getHandler(m);
// handler should never be null.
//
if (handler == null)
throw new SnmpStatusException(SnmpStatusException.noSuchInstance);
// Use the filter to retrieve only GarabageCollectorMBean data.
//
final Object data = filter.getData(handler,oid);
// data may be null if the OID we were given is not valid.
// (e.g. it identifies a MemoryManager which is not a
// GarbageCollector)
//
if (data == null)
throw new SnmpStatusException(SnmpStatusException.noSuchInstance);
// Make a new entryy (transient object that will be kept only
// for the duration of the request.
//
final Object entry =
new JvmMemGCEntryImpl((GarbageCollectorMXBean)data,(int)index);
// Put the entry in the request cache in case we need it later
// in the processing of the request. Note that we could have
// optimized this by making JvmMemGCEntryImpl extend
// JvmMemManagerEntryImpl, and then make sure that
// JvmMemManagerTableMetaImpl creates an instance of JvmMemGCEntryImpl
// instead of JvmMemManagerEntryImpl when the associated data is
// an instance of GarbageCollectorMXBean. This would have made it
// possible to share the transient entry object.
// As it is, we may have two transient objects that points to
// the same underlying MemoryManagerMXBean (which is definitely
// not a problem - but is only a small dysatisfaction)
//
if (m != null && entry != null) {
m.put(entryTag,entry);
}
return entry;
}
static final MibLogger log = new MibLogger(JvmMemGCTableMetaImpl.class);
}