[SNMP4J] Table Listeners and multi-threading

[pasteman8-agentpp at yahoo.com]

Great. Thanks!
I think this should do the job.

+gil

--- Frank Fock <fock at agentpp.com> wrote:

> pasteman8-agentpp at yahoo.com wrote:
> 
> >There is a basic question regarding the design of
> >TableUtils:
> >Can the getTable method be used in a runnable run()
> >method? In otherwords, does getTable return only
> when
> >the table is done?
> >
> >  
> >
> No, the TableUtils.getTable() method available in
> v1.0.3 asynchronously
> retrieves a table. It returns immediately. For a
> synchronously getTable
> method, please add the following code to TableUtils
> class (this code
> will be part of v1.0.4):
> 
>   /**
>    * Gets synchronously SNMP tabular data from one
> or more tables.
>    * The data is returned row-by-row as a list of
> {@link TableEvent} 
> instances.
>    * Each instance represents a row (or an error
> condition). Besides the
>    * target agent, the OIDs of the columnar objects
> have to be specified
>    * for which instances should be retrieved. With a
> lower bound index and
>    * an upper bound index, the result set can be
> narrowed to improve
>    * performance. This method can be executed
> concurrently by multiple 
> threads.
>    *
>    * @param target
>    *    a <code>Target</code> instance.
>    * @param columnOIDs
>    *    an array of OIDs of the columnar objects
> whose instances should be
>    *    retrieved. The columnar objects may belong
> to different tables.
>    *    Typically they belong to tables that share a
> common index or 
> sub-index
>    *    prefix. Note: The result of this method is
> not defined if 
> instance OIDs
>    *    are supplied in this array!
>    * @param lowerBoundIndex
>    *    an optional parameter that specifies the
> lower bound index.
>    *    If not <code>null</code>, all returned rows
> have an index 
> greater than
>    *    <code>lowerBoundIndex</code>.
>    * @param upperBoundIndex
>    *    an optional parameter that specifies the
> upper bound index.
>    *    If not <code>null</code>, all returned rows
> have an index less 
> or equal
>    *    than <code>lowerBoundIndex</code>.
>    * @return
>    *    a <code>List</code> of {@link TableEvent}
> instances. Each instance
>    *    represents successfully retrieved row or an
> error condition. Error
>    *    conditions (any status other than {@link
> TableEvent#STATUS_OK})
>    *    may only appear at the last element of the
> list.
>    */
>   public List getTable(Target target,
>                        OID[] columnOIDs,
>                        OID lowerBoundIndex,
>                        OID upperBoundIndex) {
> 
>     if ((columnOIDs == null) || (columnOIDs.length
> == 0)) {
>       throw new IllegalArgumentException("No column
> OIDs specified");
>     }
>     InternalTableListener listener = new
> InternalTableListener();
>     TableRequest req = new TableRequest(target,
> columnOIDs, listener,
>                                         null,
>                                        
> lowerBoundIndex,
>                                        
> upperBoundIndex);
>     synchronized (listener) {
>       req.sendNextChunk();
>       try {
>         listener.wait();
>       }
>       catch (InterruptedException ex) {
>         logger.warn(ex);
>       }
>     }   
>     return listener.getRows();
>   }
> 
>   class InternalTableListener implements
> TableListener {
>    
>     private LinkedList rows = new LinkedList();
>    
>     public boolean next(TableEvent event) {
>       rows.add(event);
>       return true;
>     }
> 
>     public synchronized void finished(TableEvent
> event) {
>       if ((event.getStatus() !=
> TableEvent.STATUS_OK) ||
>           (event.getIndex() != null)) {
>         rows.add(event);
>       }
>       notify();
>     }
> 
>     public List getRows() {
>       return rows;
>     }
>   }
> 
> 
> Best regards,
> Frank
> 
>