/*
* @(#)file SnmpMibGroup.java
* @(#)author Sun Microsystems, Inc.
* @(#)version 1.24
* @(#)date 05/08/26
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package com.sun.jmx.snmp.agent;
// java imports
//
import java.io.Serializable;
import java.util.Hashtable;
import java.util.Enumeration;
import java.util.Vector;
// jmx imports
//
import com.sun.jmx.snmp.SnmpOid;
import com.sun.jmx.snmp.SnmpValue;
import com.sun.jmx.snmp.SnmpVarBind;
import com.sun.jmx.snmp.SnmpStatusException;
// SNMP Runtime imports
//
import com.sun.jmx.snmp.agent.SnmpMibOid;
import com.sun.jmx.snmp.agent.SnmpMibNode;
/**
* Represents a node in an SNMP MIB which corresponds to a group.
* This class allows subnodes to be registered below a group, providing
* support for nested groups. The subnodes are registered at run time
* when registering the nested groups in the global MIB OID tree.
* <P>
* This class is used by the class generated by <CODE>mibgen</CODE>.
* You should not need to use this class directly.
*
* <p><b>This API is a Sun Microsystems internal API and is subject
* to change without notice.</b></p>
* @version 4.3 10/29/99
* @author Sun Microsystems, Inc
*/
public abstract class SnmpMibGroup extends SnmpMibOid
implements Serializable {
// We will register the OID arcs leading to subgroups in this hashtable.
// So for each arc in varList, if the arc is also in subgroups, it leads
// to a subgroup, if it is not in subgroup, it leads either to a table
// or to a variable.
protected Hashtable subgroups = null;
/**
* Tells whether the given arc identifies a table in this group.
*
* @param arc An OID arc.
*
* @return <CODE>true</CODE> if `arc' leads to a table.
*/
public abstract boolean isTable(long arc);
/**
* Tells whether the given arc identifies a variable (scalar object) in
* this group.
*
* @param arc An OID arc.
*
* @return <CODE>true</CODE> if `arc' leads to a variable.
*/
public abstract boolean isVariable(long arc);
/**
* Tells whether the given arc identifies a readable scalar object in
* this group.
*
* @param arc An OID arc.
*
* @return <CODE>true</CODE> if `arc' leads to a readable variable.
*/
public abstract boolean isReadable(long arc);
/**
* Gets the table identified by the given `arc'.
*
* @param arc An OID arc.
*
* @return The <CODE>SnmpMibTable</CODE> identified by `arc', or
* <CODE>null</CODE> if `arc' does not identify any table.
*/
public abstract SnmpMibTable getTable(long arc);
/**
* Checks whether the given OID arc identifies a variable (scalar
* object).
*
* @exception If the given `arc' does not identify any variable in this
* group, throws an SnmpStatusException.
*/
public void validateVarId(long arc, Object userData)
throws SnmpStatusException {
if (isVariable(arc) == false)
throw noSuchObjectException;
}
// -------------------------------------------------------------------
// We use a hashtable (subgroup) in order to determine whether an
// OID arc leads to a subgroup. This implementation can be changed if
// needed...
// For instance, the subclass could provide a generated isNestedArc()
// method in which the subgroup OID arcs would be hardcoded.
// However, the generic approach was prefered because at this time
// groups and subgroups are dynamically registered in the MIB.
//
/**
* Tell whether the given OID arc identifies a sub-tree
* leading to a nested SNMP sub-group. This method is used internally.
* You shouldn't need to call it directly.
*
* @param arc An OID arc.
*
* @return <CODE>true</CODE> if the given OID arc identifies a subtree
* leading to a nested SNMP sub-group.
*
*/
public boolean isNestedArc(long arc) {
if (subgroups == null) return false;
Object obj = subgroups.get(new Long(arc));
// if the arc is registered in the hashtable,
// it leads to a subgroup.
return (obj != null);
}
/**
* Generic handling of the <CODE>get</CODE> operation.
* <p>The actual implementation of this method will be generated
* by mibgen. Usually, this implementation only delegates the
* job to some other provided runtime class, which knows how to
* access the MBean. The current toolkit thus provides two
* implementations:
* <ul><li>The standard implementation will directly access the
* MBean through a java reference,</li>
* <li>The generic implementation will access the MBean through
* the MBean server.</li>
* </ul>
* <p>Both implementations rely upon specific - and distinct, set of
* mibgen generated methods.
* <p> You can override this method if you need to implement some
* specific policies for minimizing the accesses made to some remote
* underlying resources.
* <p>
*
* @param req The sub-request that must be handled by this node.
*
* @param depth The depth reached in the OID tree.
*
* @exception SnmpStatusException An error occurred while accessing
* the MIB node.
*/
abstract public void get(SnmpMibSubRequest req, int depth)
throws SnmpStatusException;
/**
* Generic handling of the <CODE>set</CODE> operation.
* <p>The actual implementation of this method will be generated
* by mibgen. Usually, this implementation only delegates the
* job to some other provided runtime class, which knows how to
* access the MBean. The current toolkit thus provides two
* implementations:
* <ul><li>The standard implementation will directly access the
* MBean through a java reference,</li>
* <li>The generic implementation will access the MBean through
* the MBean server.</li>
* </ul>
* <p>Both implementations rely upon specific - and distinct, set of
* mibgen generated methods.
* <p> You can override this method if you need to implement some
* specific policies for minimizing the accesses made to some remote
* underlying resources.
* <p>
*
* @param req The sub-request that must be handled by this node.
*
* @param depth The depth reached in the OID tree.
*
* @exception SnmpStatusException An error occurred while accessing
* the MIB node.
*/
abstract public void set(SnmpMibSubRequest req, int depth)
throws SnmpStatusException;
/**
* Generic handling of the <CODE>check</CODE> operation.
*
* <p>The actual implementation of this method will be generated
* by mibgen. Usually, this implementation only delegates the
* job to some other provided runtime class, which knows how to
* access the MBean. The current toolkit thus provides two
* implementations:
* <ul><li>The standard implementation will directly access the
* MBean through a java reference,</li>
* <li>The generic implementation will access the MBean through
* the MBean server.</li>
* </ul>
* <p>Both implementations rely upon specific - and distinct, set of
* mibgen generated methods.
* <p> You can override this method if you need to implement some
* specific policies for minimizing the accesses made to some remote
* underlying resources, or if you need to implement some consistency
* checks between the different values provided in the varbind list.
* <p>
*
* @param req The sub-request that must be handled by this node.
*
* @param depth The depth reached in the OID tree.
*
* @exception SnmpStatusException An error occurred while accessing
* the MIB node.
*/
abstract public void check(SnmpMibSubRequest req, int depth)
throws SnmpStatusException;
// --------------------------------------------------------------------
// If we reach this node, we are below the root OID, so we just
// return.
// --------------------------------------------------------------------
public void getRootOid(Vector result) {
return;
}
// -------------------------------------------------------------------
// PACKAGE METHODS
// -------------------------------------------------------------------
// -------------------------------------------------------------------
// This method can also be overriden in a subclass to provide a
// different implementation of the isNestedArc() method.
// => if isNestedArc() is hardcoded, then registerSubArc() becomes
// useless and can become empty.
/**
* Register an OID arc that identifies a sub-tree
* leading to a nested SNMP sub-group. This method is used internally.
* You shouldn't ever call it directly.
*
* @param arc An OID arc.
*
*/
void registerNestedArc(long arc) {
Long obj = new Long(arc);
if (subgroups == null) subgroups = new Hashtable();
// registers the arc in the hashtable.
subgroups.put(obj,obj);
}
// -------------------------------------------------------------------
// The SnmpMibOid algorithm relies on the fact that for every arc
// registered in varList, there is a corresponding node at the same
// position in children.
// So the trick is to register a null node in children for each variable
// in varList, so that the real subgroup nodes can be inserted at the
// correct location.
// registerObject() should be called for each scalar object and each
// table arc by the generated subclass.
/**
* Register an OID arc that identifies a scalar object or a table.
* This method is used internally. You shouldn't ever call it directly.
*
* @param arc An OID arc.
*
*/
protected void registerObject(long arc)
throws IllegalAccessException {
// this will register the variable in both varList and children
// The node registered in children will be null, so that the parent
// algorithm will behave as if no node were registered. This is a
// trick that makes the parent algorithm behave as if only subgroups
// were registered in varList and children.
long[] oid = new long[1];
oid[0] = arc;
super.registerNode(oid,0,null);
}
// -------------------------------------------------------------------
// registerNode() will be called at runtime when nested groups are
// registered in the MIB. So we do know that this method will only
// be called to register nested-groups.
// We trap registerNode() in order to call registerSubArc()
/**
* Register a child node of this node in the OID tree.
* This method is used internally. You shouldn't ever call it directly.
*
* @param oid The oid of the node being registered.
* @param cursor The position reached in the oid.
* @param node The node being registered.
*
*/
void registerNode(long[] oid, int cursor ,SnmpMibNode node)
throws IllegalAccessException {
super.registerNode(oid,cursor,node);
if (cursor < 0) return;
if (cursor >= oid.length) return;
// if we get here, then it means we are registering a subgroup.
// We will thus register the sub arc in the subgroups hashtable.
registerNestedArc(oid[cursor]);
}
// -------------------------------------------------------------------
// see comments in SnmpMibNode
// -------------------------------------------------------------------
void findHandlingNode(SnmpVarBind varbind,
long[] oid, int depth,
SnmpRequestTree handlers)
throws SnmpStatusException {
int length = oid.length;
SnmpMibNode node = null;
if (handlers == null)
throw new SnmpStatusException(SnmpStatusException.snmpRspGenErr);
final Object data = handlers.getUserData();
if (depth >= length) {
// Nothing is left... the oid is not valid
throw new SnmpStatusException(SnmpStatusException.noAccess);
}
long arc = oid[depth];
if (isNestedArc(arc)) {
// This arc leads to a subgroup: delegates the search to the
// method defined in SnmpMibOid
super.findHandlingNode(varbind,oid,depth,handlers);
return;
} else if (isTable(arc)) {
// This arc leads to a table: forward the search to the table.
// Gets the table
SnmpMibTable table = getTable(arc);
// Forward the search to the table
table.findHandlingNode(varbind,oid,depth+1,handlers);
} else {
// If it's not a variable, throws an exception
validateVarId(arc, data);
// The trailing .0 is missing in the OID
if (depth+2 > length)
throw noSuchInstanceException;
// There are too many arcs left in the OID (there should remain
// a single trailing .0)
if (depth+2 < length)
throw noSuchInstanceException;
// The last trailing arc is not .0
if (oid[depth+1] != 0L)
throw noSuchInstanceException;
// It's one of our variable, register this node.
handlers.add(this,depth,varbind);
}
}
// -------------------------------------------------------------------
// See comments in SnmpMibNode.
// -------------------------------------------------------------------
long[] findNextHandlingNode(SnmpVarBind varbind,
long[] oid, int pos, int depth,
SnmpRequestTree handlers, AcmChecker checker)
throws SnmpStatusException {
int length = oid.length;
SnmpMibNode node = null;
if (handlers == null)
// This should be considered as a genErr, but we do not want to
// abort the whole request, so we're going to throw
// a noSuchObject...
//
throw noSuchObjectException;
final Object data = handlers.getUserData();
final int pduVersion = handlers.getRequestPduVersion();
// The generic case where the end of the OID has been reached is
// handled in the superclass
// XXX Revisit: this works but it is somewhat convoluted. Just setting
// arc to -1 would work too.
if (pos >= length)
return super.findNextHandlingNode(varbind,oid,pos,depth,
handlers, checker);
// Ok, we've got the arc.
long arc = oid[pos];
long[] result = null;
// We have a recursive logic. Should we have a loop instead?
try {
if (isTable(arc)) {
// If the arc identifies a table, then we need to forward
// the search to the table.
// Gets the table identified by `arc'
SnmpMibTable table = getTable(arc);
// Forward to the table
checker.add(depth, arc);
try {
result = table.findNextHandlingNode(varbind,oid,pos+1,
depth+1,handlers,
checker);
}catch(SnmpStatusException ex) {
throw noSuchObjectException;
} finally {
checker.remove(depth);
}
// Build up the leaf OID
result[depth] = arc;
return result;
} else if (isReadable(arc)) {
// If the arc identifies a readable variable, then two cases:
if (pos == (length - 1)) {
// The end of the OID is reached, so we return the leaf
// corresponding to the variable identified by `arc'
// Build up the OID
// result = new SnmpOid(0);
// result.insert((int)arc);
result = new long[depth+2];
result[depth+1] = 0L;
result[depth] = arc;
checker.add(depth, result, depth, 2);
try {
checker.checkCurrentOid();
} catch(SnmpStatusException e) {
throw noSuchObjectException;
} finally {
checker.remove(depth,2);
}
// Registers this node
handlers.add(this,depth,varbind);
return result;
}
// The end of the OID is not yet reached, so we must return
// the next leaf following the variable identified by `arc'.
// We cannot return the variable because whatever follows in
// the OID will be greater or equals to 0, and 0 identifies
// the variable itself - so we have indeed to return the
// next object.
// So we do nothing, because this case is handled at the
// end of the if ... else if ... else ... block.
} else if (isNestedArc(arc)) {
// Now if the arc leads to a subgroup, we delegate the
// search to the child, just as done in SnmpMibNode.
//
// get the child ( = nested arc node).
//
final SnmpMibNode child = getChild(arc);
if (child != null) {
checker.add(depth, arc);
try {
result = child.findNextHandlingNode(varbind,oid,pos+1,
depth+1,handlers,
checker);
result[depth] = arc;
return result;
} finally {
checker.remove(depth);
}
}
}
// The oid is not valid, we will throw an exception in order
// to try with the next valid identifier...
//
throw noSuchObjectException;
} catch (SnmpStatusException e) {
// We didn't find anything at the given arc, so we're going
// to try with the next valid arc
//
long[] newOid = new long[1];
newOid[0] = getNextVarId(arc,data,pduVersion);
return findNextHandlingNode(varbind,newOid,0,depth,
handlers,checker);
}
}
}
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