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* accompanied this code).
*
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package com.sun.jmx.snmp.agent;
import com.sun.jmx.snmp.SnmpPduPacket;
import com.sun.jmx.snmp.SnmpPdu;
import com.sun.jmx.snmp.SnmpStatusException;
/**
* This interface is provided to enable fine customization of the SNMP
* agent behaviour.
*
* <p>You will not need to implement this interface except if your agent
* needs extra customization requiring some contextual information.</p>
*
* <p>If an SnmpUserDataFactory is set on the SnmpAdaptorServer, then a new
* object containing user-data will be allocated through this factory
* for each incoming request. This object will be passed along to
* the SnmpMibAgent within SnmpMibRequest objects. By default, no
* SnmpUserDataFactory is set on the SnmpAdaptorServer, and the contextual
* object passed to SnmpMibAgent is null.</p>
*
* <p>You can use this feature to obtain on contextual information
* (such as community string etc...) or to implement a caching
* mechanism, or for whatever purpose might be required by your specific
* agent implementation.</p>
*
* <p>The sequence <code>allocateUserData() / releaseUserData()</code> can
* also be used to implement a caching mechanism:
* <ul>
* <li><code>allocateUserData()</code> could be used to allocate
* some cache space,</li>
* <li>and <code>releaseUserData()</code> could be used to flush it.</li>
* </ul></p>
*
* <p><b>This API is a Sun Microsystems internal API and is subject
* to change without notice.</b></p>
* @see com.sun.jmx.snmp.agent.SnmpMibRequest
* @see com.sun.jmx.snmp.agent.SnmpMibAgent
* @see com.sun.jmx.snmp.daemon.SnmpAdaptorServer
*
**/
public interface SnmpUserDataFactory {
/**
* Called by the <CODE>SnmpAdaptorServer</CODE> adaptor.
* Allocate a contextual object containing some user data. This method
* is called once for each incoming SNMP request. The scope
* of this object will be the whole request. Since the request can be
* handled in several threads, the user should make sure that this
* object can be accessed in a thread-safe manner. The SNMP framework
* will never access this object directly - it will simply pass
* it to the <code>SnmpMibAgent</code> within
* <code>SnmpMibRequest</code> objects - from where it can be retrieved
* through the {@link com.sun.jmx.snmp.agent.SnmpMibRequest#getUserData() getUserData()} accessor.
* <code>null</code> is considered to be a valid return value.
*
* This method is called just after the SnmpPduPacket has been
* decoded.
*
* @param requestPdu The SnmpPduPacket received from the SNMP manager.
* <b>This parameter is owned by the SNMP framework and must be
* considered as transient.</b> If you wish to keep some of its
* content after this method returns (by storing it in the
* returned object for instance) you should clone that
* information.
*
* @return A newly allocated user-data contextual object, or
* <code>null</code>
* @exception SnmpStatusException If an SnmpStatusException is thrown,
* the request will be aborted.
*
* @since 1.5
**/
public Object allocateUserData(SnmpPdu requestPdu)
throws SnmpStatusException;
/**
* Called by the <CODE>SnmpAdaptorServer</CODE> adaptor.
* Release a previously allocated contextual object containing user-data.
* This method is called just before the responsePdu is sent back to the
* manager. It gives the user a chance to alter the responsePdu packet
* before it is encoded, and to free any resources that might have
* been allocated when creating the contextual object.
*
* @param userData The contextual object being released.
* @param responsePdu The SnmpPduPacket that will be sent back to the
* SNMP manager.
* <b>This parameter is owned by the SNMP framework and must be
* considered as transient.</b> If you wish to keep some of its
* content after this method returns you should clone that
* information.
*
* @exception SnmpStatusException If an SnmpStatusException is thrown,
* the responsePdu is dropped and nothing is returned to
* to the manager.
*
* @since 1.5
**/
public void releaseUserData(Object userData, SnmpPdu responsePdu)
throws SnmpStatusException;
}