org.globus.mds.aggregator.impl
Class PollingAggregatorSource

java.lang.Object
  org.globus.mds.aggregator.impl.PollingAggregatorSource

All Implemented Interfaces:

AggregatorSource

Direct Known Subclasses:

ExecutionAggregatorSource, QueryAggregatorSource

public abstract class PollingAggregatorSource

extends java.lang.Object

implements AggregatorSource

An AggregatorSource which generates data using synchronous polling in a background thread. The class is abstract, and requires subclassing to provide the implementation of the poll action.

Nested Class Summary

class

PollingAggregatorSource.QueryTimerListener One instance of this class will be created for each aggregation

Field Summary

static int	DEFAULT_POLL_INTERVAL
private boolean	initialized
private static org.apache.commons.logging.Log	logger
private java.util.Hashtable	sessions This Map maps from session keys (String instances) to session context (QueryTimerListener instances)
private AggregatorSink	sink
private java.lang.Object	sinkParameters
private TimerManagerImpl	timerManager

Constructor Summary

PollingAggregatorSource(AggregatorSink sink)

PollingAggregatorSource(AggregatorSink sink, java.lang.Object sinkParameters)
Creates a new instance of PollingAggregatorSource

Method Summary

java.lang.String	addAggregation(java.lang.Object parameters, AggregatorServiceGroupEntryResource entry) Establishes an implementation-specific data aggregation session.
abstract AggregatorPollType	deserializeParameter(org.apache.axis.message.MessageElement m) If the supplied message element is a supported parameter block, the deserialised form should be returned; otherwise null should be returned.
AggregatorSink	getAggregatorSink() Gets the AggregatorSink instance where data from the underlying AggregatorSource will be routed, or NULL if not set.
AggregatorServiceGroupEntryResource	getSessionContext(java.lang.String sessionKey) Retrieve AggregatorServiceGroupEntryResource entry context.
java.lang.String	getSessionKey(AggregatorServiceGroupEntryResource entry) Get a sessionKey from a given entry context.
void	initialize(java.lang.Object parameters) Called to initialize any necessary state.
boolean	isValidSession(java.lang.String sessionKey) Determines if a specified sessionKey is valid (active).
abstract org.apache.axis.encoding.AnyContentType	poll(AggregatorPollType parameters, org.apache.axis.message.addressing.EndpointReferenceType epr, AggregatorConfig config) This method must be implemented by subclasses to provide the specific specialised poll implementation.
void	removeAggregation(java.lang.String sessionKey) Terminates the data aggregation represented by sessionKey.
void	setAggregatorSink(AggregatorSink sink, java.lang.Object sinkParameters) Sets the AggregatorSink instance where data from the Aggregator Source will be routed.
void	terminate() Called to free resources used by the source.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_POLL_INTERVAL

public static final int DEFAULT_POLL_INTERVAL

See Also:

Constant Field Values

sink

private AggregatorSink sink

sinkParameters

private java.lang.Object sinkParameters

sessions

private java.util.Hashtable sessions

This Map maps from session keys (String instances) to session context (QueryTimerListener instances)

timerManager

private TimerManagerImpl timerManager

initialized

private boolean initialized

logger

private static org.apache.commons.logging.Log logger

Constructor Detail

PollingAggregatorSource

public PollingAggregatorSource(AggregatorSink sink,
                               java.lang.Object sinkParameters)

Creates a new instance of PollingAggregatorSource

PollingAggregatorSource

public PollingAggregatorSource(AggregatorSink sink)

Method Detail

initialize

public void initialize(java.lang.Object parameters)
                throws AggregatorException,
                       java.lang.Exception

Description copied from interface: AggregatorSource

Called to initialize any necessary state. This method should also attempt to initialize the specified sink and should always throw an exception if the sink is not set. The underlying implementation should throw an AggregatorSinkTypeNotSupportedException if it is not compatible with the supplied AggregationSink. The implementation may use the optional parameters Object to read implementation specific data from or just ignore the processing of it altogether.

Specified by:

initialize in interface AggregatorSource

Throws:

AggregatorException

java.lang.Exception

getSessionContext

public AggregatorServiceGroupEntryResource getSessionContext(java.lang.String sessionKey)

Description copied from interface: AggregatorSource

Retrieve AggregatorServiceGroupEntryResource entry context.

Specified by:

getSessionContext in interface AggregatorSource

Parameters:

sessionKey - The session key of the aggregation.

Returns:

A valid object, or NULL. The type of object returned is dependent on the underlying implementation.

getSessionKey

public java.lang.String getSessionKey(AggregatorServiceGroupEntryResource entry)
                               throws AggregatorException

Description copied from interface: AggregatorSource

Get a sessionKey from a given entry context.

Specified by:

getSessionKey in interface AggregatorSource

Returns:

A string representing the sessionKey for the given entry.

Throws:

AggregatorException

isValidSession

public boolean isValidSession(java.lang.String sessionKey)
                       throws AggregatorException

Description copied from interface: AggregatorSource

Determines if a specified sessionKey is valid (active).

Specified by:

isValidSession in interface AggregatorSource

Returns:

A boolean value indicating whether the specified sessionKey is valid.

Throws:

AggregatorException

getAggregatorSink

public AggregatorSink getAggregatorSink()

Description copied from interface: AggregatorSource

Gets the AggregatorSink instance where data from the underlying AggregatorSource will be routed, or NULL if not set.

Specified by:

getAggregatorSink in interface AggregatorSource

setAggregatorSink

public void setAggregatorSink(AggregatorSink sink,
                              java.lang.Object sinkParameters)

Description copied from interface: AggregatorSource

Sets the AggregatorSink instance where data from the Aggregator Source will be routed.

Specified by:

setAggregatorSink in interface AggregatorSource

addAggregation

public java.lang.String addAggregation(java.lang.Object parameters,
                                       AggregatorServiceGroupEntryResource entry)
                                throws AggregatorParamTypeNotSupportedException,
                                       AggregatorException,
                                       java.lang.Exception

Description copied from interface: AggregatorSource

Establishes an implementation-specific data aggregation session. The method of data collection and consumption is defined by the implementation; the contract of the interface is that any data generated should be capable of being consumed by a class implementing the AggregationSink interface, which will in turn be bound an AggregationSource.

Specified by:

addAggregation in interface AggregatorSource

Parameters:

parameters - Implementation-specific parameters of the data to be collected.

entry - The AggregatorServiceGroupEntryResource instance to associate with this aggregation session. This instance will be passed unmodified to any connected AggregationSink.

Returns:

A session key, which is a String which must be guaranteed by the underlying AggregatorSource implementation to be a unique token with respect to all other invocations of the addAggregation method with the same parameters and entry instance on the same AggregationSource instance. A null return value is not permitted, though the empty string "" is.
An exception MUST be thrown if the aggregation could not be created by the implementation.

Throws:

AggregatorParamTypeNotSupportedException

AggregatorException

java.lang.Exception

removeAggregation

public void removeAggregation(java.lang.String sessionKey)
                       throws AggregatorException,
                              java.lang.Exception

Description copied from interface: AggregatorSource

Terminates the data aggregation represented by sessionKey.

Specified by:

removeAggregation in interface AggregatorSource

Parameters:

sessionKey - The session key of the aggregation to terminate.

Throws:

AggregatorException

java.lang.Exception

terminate

public void terminate()

Description copied from interface: AggregatorSource

Called to free resources used by the source.

Specified by:

terminate in interface AggregatorSource

poll

public abstract org.apache.axis.encoding.AnyContentType poll(AggregatorPollType parameters,
                                                             org.apache.axis.message.addressing.EndpointReferenceType epr,
                                                             AggregatorConfig config)

This method must be implemented by subclasses to provide the specific specialised poll implementation. It will be called by the PollingAggregatorSource implementation every time it is time to poll for data. TODO: this method signature is getting a little messy... tidy up

deserializeParameter

public abstract AggregatorPollType deserializeParameter(org.apache.axis.message.MessageElement m)
                                                 throws DeserializationException

If the supplied message element is a supported parameter block, the deserialised form should be returned; otherwise null should be returned. This method will be invoked on all config parameters supplied to an aggregation until one is found that matches.

Throws:

DeserializationException