it.jnrpe.plugins
Class PluginBase

java.lang.Object
  it.jnrpe.plugins.PluginBase

All Implemented Interfaces:

IPluginInterface, IPluginInterfaceEx

Direct Known Subclasses:

PluginProxy

public abstract class PluginBase
extends Object
implements IPluginInterfaceEx

This class facilitates the implementation of plugins. If you don't need to extend other classes, than extending PluginBase is the best way. This class gives you out of the box:

• Logging through the log variable.
• Events: you can easily send events by using the sendEvent methods.
• Threshold evaluation: by overriding the gatherMetrics(ICommandLine) you can demand to this class all the work required to evaluate thresholds. If you use the new threshold syntax, all the configuration is done automatically. Otherwise you just have to override the configureThresholdEvaluatorBuilder(ThresholdsEvaluatorBuilder, ICommandLine) to set the all the thresholds.

Author:

Massimiliano Ziccardi

Nested Class Summary

protected class

PluginBase.Logger This class represent a generic logger that will be used by plugins extending the PluginBase to write logs.

Field Summary

protected PluginBase.Logger

log The logger object.

Constructor Summary

PluginBase()

Method Summary

void	addListener(IJNRPEEventListener listener) Adds a new listener to the list of objects that will receive the messages sent by this class.
void	addListeners(Collection<IJNRPEEventListener> listeners) Adds a new collection of listeners.
void	configureThresholdEvaluatorBuilder(ThresholdsEvaluatorBuilder thrb, ICommandLine cl) Override this method if you don't use the new threshold syntax.
ReturnValue	execute(ICommandLine cl) Executes the plugin.
Collection<Metric>	gatherMetrics(ICommandLine cl) This method must be overridden if you don't override the execute(ICommandLine) method.
protected Set<IJNRPEEventListener>	getListeners() Returns all the registered listeners.
protected abstract String	getPluginName()
void	sendEvent(LogEvent evt, String message) Sends an event.
void	sendEvent(LogEvent evt, String message, Exception exc) Sends an event.
void	sendEvent(String customEventName, EventParam... paramsAry) Sends a custom event.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

protected final PluginBase.Logger log

The logger object.

Constructor Detail

PluginBase

public PluginBase()

Method Detail

addListener

public final void addListener(IJNRPEEventListener listener)

Adds a new listener to the list of objects that will receive the messages sent by this class.

Specified by:

addListener in interface IPluginInterfaceEx

Parameters:

listener - The new listener

addListeners

public final void addListeners(Collection<IJNRPEEventListener> listeners)

Adds a new collection of listeners.

Specified by:

addListeners in interface IPluginInterfaceEx

Parameters:

listeners - The collection of listeners to be added

sendEvent

public final void sendEvent(LogEvent evt,
                            String message)

Sends an event.

Parameters:

evt - The event type

message - The message

sendEvent

public final void sendEvent(LogEvent evt,
                            String message,
                            Exception exc)

Sends an event.

Parameters:

evt - The event type

message - The message

exc - The exception to be attached to the event

sendEvent

public final void sendEvent(String customEventName,
                            EventParam... paramsAry)

Sends a custom event.

Parameters:

customEventName - The custom event identifier

paramsAry - The parameter of the event. Can be null.

getPluginName

protected abstract String getPluginName()

Returns:

the friendly name of this plugins.

getListeners

protected final Set<IJNRPEEventListener> getListeners()

Returns all the registered listeners.

Returns:

All the listeners

configureThresholdEvaluatorBuilder

public void configureThresholdEvaluatorBuilder(ThresholdsEvaluatorBuilder thrb,
                                               ICommandLine cl)
                                        throws BadThresholdException

Override this method if you don't use the new threshold syntax. Here you must tell the threshold evaluator all the threshold it must be able to evaluate. Give a look at the source of the CheckOracle plugin for an example of a plugin that supports both old and new syntax.

Parameters:

thrb - The ThresholdsEvaluatorBuilder object to be configured

cl - The command line

Throws:

BadThresholdException - -

gatherMetrics

public Collection<Metric> gatherMetrics(ICommandLine cl)
                                 throws MetricGatheringException

This method must be overridden if you don't override the execute(ICommandLine) method. This way you can demand all the work about evaluating the thresholds to this class.

Parameters:

cl - The command line.

Returns:

All the collected metrics

Throws:

MetricGatheringException - -

execute

public ReturnValue execute(ICommandLine cl)
                    throws BadThresholdException

Executes the plugin. You must override this method if you want total control about what the plugins does. Most of the times, however, you'll want to override the gatherMetrics(ICommandLine) instead.

Specified by:

execute in interface IPluginInterface

Parameters:

cl - The command line

Returns:

The return value to be sent to Nagios.

Throws:

BadThresholdException - -