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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* 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).
*
* You should have received a copy of the GNU General Public License version
* 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.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.
*/
public class JvmMemGCTableMetaImpl extends JvmMemGCTableMeta {
/**
* 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
* <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
* <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.
**/
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 <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".
*/
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
**/
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);
}