Vwm (MMBase 1.9-SNAPSHOT

java.lang.Object
- org.mmbase.module.builders.vwms.Vwm

All Implemented Interfaces:

Runnable, VwmInterface, VwmProbeInterface, MMBaseObserver

Direct Known Subclasses:

ImageMaster, PageMaster
```
public class Vwm
extends Object
implements VwmInterface, VwmProbeInterface, Runnable
```
Virtual Web Master base object. Most VWM's inherit fromt his base class. The Vwm contains routines for performing tasks at certain intervals. The interval is determined from the maintime value in the Vwms builder (Maintenance time in seconds), Each interval, the vwm invokes the ProbeCall() method. VWMs perform periodic maintenance by overrideing the probeCall method (the default doesn't do anything). A VWM is also called a 'Bot'.

Version:

$Id$

Author:

Daniel Ockeloen, Pierre van Rooden (javadocs)

Application:

VWMs

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) Vector<VwmCallBackInterface>`	`clients` What clients are using this VWM.
`(package private) Thread`	`kicker` Thread in which the VWM runs.
`protected String`	`name` Name of the VWM.
`protected VwmProbe`	`probe` Scheduler of tasks depending on VWMtask nodes associated with this Vwm.
`protected int`	`sleeptime` Sleep time in seconds.
`protected Vwms`	`Vwms` The VWMs builder that holds the VWM's node.
`protected MMObjectNode`	`wvmnode` The creation node of this VWM.

Constructor Summary

Constructors
Constructor and Description

Vwm()

Constructors
Constructor and Description
`Vwm()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`addClient(VwmCallBackInterface client)` Add a client to the listen queue of the wvm.
`protected boolean`	`claim(MMObjectNode node)` Signals that the task node is claimed.
`protected void`	`debug(String msg)`
`protected boolean`	`failed(MMObjectNode node)` Signals that the task to be performed failed.
`String`	`getName()` Returns the name of the VWM.
`MMObjectNode`	`getVwmNode()` Retrieves the creation node of this VWM.
`void`	`init(MMObjectNode vwmnode, Vwms Vwms)` Initialize the Vwm.
`boolean`	`nodeLocalChanged(String machine, String number, String builder, String ctype)` Called when a remote node is changed.
`boolean`	`nodeRemoteChanged(String machine, String number, String builder, String ctype)` Called when a local node is changed.
`protected Hashtable`	`parseProperties(String props)` Converts a string of properties to a Hashtable.
`protected boolean`	`performed(MMObjectNode node)` Signals that the task to be performed was successful and has finished.
`boolean`	`performTask(MMObjectNode node)` Performs maintenance based on a Vwmtasknode.
`boolean`	`probeCall()` Performs periodic maintenance.
`boolean`	`putTask(MMObjectNode node)` Adds a new task to the list of taks to perform.
`boolean`	`releaseClient(VwmCallBackInterface client)` Release a client from the listen queue of the wvm.
`protected boolean`	`rollback(MMObjectNode node)` Signals that the task should be performed again (possibly after an initial failure).
`void`	`run()` VWM maintenance scheduler.
`void`	`start()` Starts the thread for the Vwm.
`void`	`stop()` Stops the Vwm's thread.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - probe
```
protected VwmProbe probe
```
    Scheduler of tasks depending on VWMtask nodes associated with this Vwm.
  - sleeptime
```
protected int sleeptime
```
    Sleep time in seconds. This is the interval in which the VWM performs it's maintenance probes.
  - wvmnode
```
protected MMObjectNode wvmnode
```
    The creation node of this VWM. Used to retrieve the maintenance time and to maintain VWM state information.
  - name
```
protected String name
```
    Name of the VWM. Retrieved from the node from the VWMs builder, but can also be set manually by the VWM's overriding class.
  - Vwms
```
protected Vwms Vwms
```
    The VWMs builder that holds the VWM's node. The same as the parent attribute of the vwm node (but a bit easier in use).
    
    See Also:
    
    getVwmNode()
  - kicker
```
Thread kicker
```
    Thread in which the VWM runs. This field can be used to stop the VWM. Setting kicker to null (either from outside the thread or within) will cause the VWM to terminate it's run() method.
  - clients
```
Vector<VwmCallBackInterface> clients
```
    What clients are using this VWM. Each client implements the VwmCallBackInterface, and can be invoked when important changes occur.
- Constructor Detail
  - Vwm
```
public Vwm()
```
- Method Detail
  - debug
```
protected void debug(String msg)
```
  - init
```
public void init(MMObjectNode vwmnode,
                 Vwms Vwms)
```
    Initialize the Vwm. Called by the Vwms builder that starts the VWM. Sets a few fields, creates a new probe instance, and starts a new thread.
    
    Specified by:
    
    init in interface VwmInterface
    
    Parameters:
    
    vwmnode -
    
    Vwms - The VWMs builder. It is not really necessary as this is the same as the parent attribute of vwmnode.
  - start
```
public void start()
```
    Starts the thread for the Vwm.
  - stop
```
public void stop()
```
    Stops the Vwm's thread. Sets the kicker field to null, which causes the run method to terminate.
  - run
```
public void run()
```
    VWM maintenance scheduler. Calls the probeCall() method, after which the thread sleeps for a number of seconds as set in sleeptime.
    
    Specified by:
    
    run in interface Runnable
  - addClient
```
public boolean addClient(VwmCallBackInterface client)
```
    Add a client to the listen queue of the wvm.
    
    Specified by:
    
    addClient in interface VwmInterface
    
    Parameters:
    
    client - The client-object to add
    
    Returns:
    
    true if the client was added, false if it already existed in the queue.
  - releaseClient
```
public boolean releaseClient(VwmCallBackInterface client)
```
    Release a client from the listen queue of the wvm.
    
    Specified by:
    
    releaseClient in interface VwmInterface
    
    Parameters:
    
    client - The client-object to release
    
    Returns:
    
    true if the client was released, false if it did not exist in the queue.
  - probeCall
```
public boolean probeCall()
```
    Performs periodic maintenance. This method is called by the VWM's own run() method. Since this does not actually do anything, perhaps this method should be abstract.
    
    Specified by:
    
    probeCall in interface VwmProbeInterface
    
    Returns:
    
    true if maintenance was performed, false otherwise
  - putTask
```
public boolean putTask(MMObjectNode node)
```
    Adds a new task to the list of taks to perform. Passes the task to the VWM's probe, which handles the of tasks.
    
    Parameters:
    
    node - the node describing the task (from the Vwmtasks builder)
    
    Returns:
    
    true is the task was succesfully added.
  - getName
```
public String getName()
```
    Returns the name of the VWM.
    
    Specified by:
    
    getName in interface VwmProbeInterface
  - performTask
```
public boolean performTask(MMObjectNode node)
```
    Performs maintenance based on a Vwmtasknode. This method is called by the probe object assoviated with the VWM. the default method sets a status field to indicate an error, and sends an error email. Perhaps this method should be abstract.
    
    Specified by:
    
    performTask in interface VwmProbeInterface
    
    Parameters:
    
    node - The Vwmtask node that describes the task to be performed.
    
    Returns:
    
    true if maintenance was performed, false if it failed
  - claim
```
protected boolean claim(MMObjectNode node)
```
    Signals that the task node is claimed. Sets the status of the task to 'claimed', as well as the machinename that is claiming the task. Setting a task to 'claimed' prevents it from being scheduled for performance by the Vwmtask builder.
    
    Parameters:
    
    node - The VwmTask node that describes the task
    
    Returns:
    
    true if teh task's state was cahnged, false if it fails.
  - rollback
```
protected boolean rollback(MMObjectNode node)
```
    Signals that the task should be performed again (possibly after an initial failure). Sets the status of the task to 'request'. Setting a task to 'request' allows it to be scheduled for performance by the Vwmtask builder.
    
    Parameters:
    
    node - The VwmTask node that describes the task
    
    Returns:
    
    true if teh task's state was cahnged, false if it fails.
  - failed
```
protected boolean failed(MMObjectNode node)
```
    Signals that the task to be performed failed. Sets the status of the task to 'error'. Setting a task to 'error' prevents it from being scheduled for performance by the Vwmtask builder.
    
    Parameters:
    
    node - The VwmTask node that describes the task
    
    Returns:
    
    true if the task's state was cahnged, false if it fails.
  - performed
```
protected boolean performed(MMObjectNode node)
```
    Signals that the task to be performed was successful and has finished. Sets the status of the task to 'done'. Setting a task to 'done' prevents it from being scheduled for performance by the Vwmtask builder.
    
    Parameters:
    
    node - The VwmTask node that describes the task
    
    Returns:
    
    true if teh task's state was cahnged, false if it fails.
  - parseProperties
```
protected Hashtable parseProperties(String props)
```
    Converts a string of properties to a Hashtable. Used to parse the 'data' field of a VwmTask node. The property format is a string with a property on each line in the format: name = value Very generic, should probably be moved to the MMObjectNode class (as in getPropertiesValue(fieldname) ).
    
    Parameters:
    
    props - the properties string
    
    Returns:
    
    a hashtable with the property name=value pairs.
  - getVwmNode
```
public MMObjectNode getVwmNode()
```
    Retrieves the creation node of this VWM.
  - nodeRemoteChanged
```
public boolean nodeRemoteChanged(String machine,
                                 String number,
                                 String builder,
                                 String ctype)
```
    Called when a local node is changed.
    
    Specified by:
    
    nodeRemoteChanged in interface MMBaseObserver
    
    Parameters:
    
    machine - Name of the machine that changed the node.
    
    number - Number of the changed node as a String
    
    builder - type of the changed node
    
    ctype - command type, 'c'=changed, 'd'=deleted', 'r'=relations changed, 'n'=new
    
    Returns:
    
    true if maintenance was performed, false (the default) otherwise
  - nodeLocalChanged
```
public boolean nodeLocalChanged(String machine,
                                String number,
                                String builder,
                                String ctype)
```
    Called when a remote node is changed.
    
    Specified by:
    
    nodeLocalChanged in interface MMBaseObserver
    
    Parameters:
    
    machine - Name of the machine that changed the node.
    
    number - Number of the changed node as a String
    
    builder - type of the changed node
    
    ctype - command type, 'c'=changed, 'd'=deleted', 'r'=relations changed, 'n'=new
    
    Returns:
    
    true if maintenance was performed, false (the default) otherwise

Class Vwm

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

probe

sleeptime

wvmnode

name

Vwms

kicker

clients

Constructor Detail

Vwm

Method Detail

debug

init

start

stop

run

addClient

releaseClient

probeCall

putTask

getName

performTask

claim

rollback

failed

performed

parseProperties

getVwmNode

nodeRemoteChanged

nodeLocalChanged