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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,
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*
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package sun.management.snmp.jvminstr;
// java imports
//
import com.sun.jmx.mbeanserver.Util;
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.ManagementFactory;
import sun.management.snmp.jvmmib.JvmMemManagerTableMeta;
import sun.management.snmp.util.SnmpTableCache;
import sun.management.snmp.util.SnmpNamedListTableCache;
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 "JvmMemManagerTable" table.
*
* This custom implementation show how to implement an SNMP table
* over a weak cache, recomputing the cahed data when needed.
*/
public class JvmMemManagerTableMetaImpl extends JvmMemManagerTableMeta {
/**
* A concrete implementation of {@link SnmpNamedListTableCache}, for the
* jvmMemManagerTable.
**/
private static class JvmMemManagerTableCache
extends SnmpNamedListTableCache {
/**
* Create a weak cache for the jvmMemManagerTable.
* @param validity validity of the cached data, in ms.
**/
JvmMemManagerTableCache(long validity) {
this.validity = validity;
}
/**
* Use the MemoryManagerMXBean name as key.
* @param context A {@link TreeMap} as allocated by the parent
* {@link SnmpNamedListTableCache} class.
* @param rawDatas List of {@link MemoryManagerMXBean}, as
* returned by
* <code>ManagementFactory.getMemoryMBean().getMemoryManagers()</code>
* @param rank The <var>rank</var> of <var>item</var> in the list.
* @param item The <var>rank</var><super>th</super>
* <code>MemoryManagerMXBean</code> in the list.
* @return <code>((MemoryManagerMXBean)item).getName()</code>
**/
protected String getKey(Object context, List rawDatas,
int rank, Object item) {
if (item == null) return null;
final String name = ((MemoryManagerMXBean)item).getName();
log.debug("getKey", "key=" + name);
return name;
}
/**
* Call <code>getTableHandler(JvmContextFactory.getUserData())</code>.
**/
public SnmpTableHandler getTableHandler() {
final Map userData = JvmContextFactory.getUserData();
return getTableDatas(userData);
}
/**
* Return the key used to cache the raw data of this table.
**/
protected String getRawDatasKey() {
return "JvmMemManagerTable.getMemoryManagers";
}
/**
* Call ManagementFactory.getMemoryManagerMXBeans() to
* load the raw data of this table.
**/
protected List loadRawDatas(Map userData) {
return ManagementFactory.getMemoryManagerMXBeans();
}
}
// The weak cache for this table.
protected SnmpTableCache cache;
/**
* Constructor for the table. Initialize metadata for
* "JvmMemManagerTableMeta".
* The reference on the MBean server is updated so the entries
* created through an SNMP SET will be AUTOMATICALLY REGISTERED
* in Java DMK.
*/
public JvmMemManagerTableMetaImpl(SnmpMib myMib,
SnmpStandardObjectServer objserv) {
super(myMib,objserv);
this.cache = new
JvmMemManagerTableCache(((JVM_MANAGEMENT_MIB_IMPL)myMib).
validity());
}
// 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();
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
//
final SnmpOid next = handler.getNext(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;
}
// 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 handler.contains(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();
// 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:("JvmMemManagerTable.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;
}
// The entry was not in the 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);
// Get the data associated with our entry.
//
final Object data = handler.getData(oid);
// data may be null if the OID we were given is not valid.
//
if (data == null)
throw new SnmpStatusException(SnmpStatusException.noSuchInstance);
// make the new entry (transient object that will be kept only
// for the duration of the request.
//
final Object entry =
new JvmMemManagerEntryImpl((MemoryManagerMXBean)data,(int)index);
// Put the entry in the cache in case we need it later while processing
// the request.
//
if (m != null && entry != null) {
m.put(entryTag,entry);
}
return entry;
}
/**
* Get the SnmpTableHandler that holds the jvmMemManagerTable data.
* First look it up in the request contextual cache, and if it is
* not found, obtain it from the weak cache.
* <br>The request contextual cache will be released at the end of the
* current requests, and is used only to process this request.
* <br>The weak cache is shared by all requests, and is only
* recomputed when it is found to be obsolete.
* <br>Note that the data put in the request contextual cache is
* never considered to be obsolete, in order to preserve data
* coherency.
**/
protected SnmpTableHandler getHandler(Object userData) {
final Map<Object, Object> m;
if (userData instanceof Map) m=Util.cast(userData);
else m=null;
// Look in the contextual cache.
if (m != null) {
final SnmpTableHandler handler =
(SnmpTableHandler)m.get("JvmMemManagerTable.handler");
if (handler != null) return handler;
}
// No handler in contextual cache, make a new one.
final SnmpTableHandler handler = cache.getTableHandler();
if (m != null && handler != null )
m.put("JvmMemManagerTable.handler",handler);
return handler;
}
static final MibLogger log =
new MibLogger(JvmMemManagerTableMetaImpl.class);
}