ds.granules.dataset

Interface Dataset

All Superinterfaces:

FormatMarshaller

All Known Subinterfaces:

FileAccess, FileDataset, StreamDataset, StreamingAccess

All Known Implementing Classes:

FileDatasetImpl, FileDatasetImplLegacy, StreamDatasetImpl, StreamDatasetImplLegacy

public interface Dataset
extends FormatMarshaller

The interface outlines the core functionalities that need to be supported within datasets. There can be different kinds of datasets: streams, files (pointers thereto), URIs, databases and objects.

Author:

Shrideep Pallickara

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Dataset.DatasetType

Method Summary

Modifier and Type	Method and Description
boolean	close() Close access to this dataset.
DataAvailabilityNotifier	getDataAvailabilityNotifier() Retrieve the data availability notifier for this dataset.
Dataset.DatasetType	getDatasetType() Retrieve the type of the data set
java.lang.String	getDescription() Retrieve a description of the dataset
java.lang.String	getIdentifier() Retrieve the identifier for this dataset.
long	getLastModificationTime() Retrieve the last update to this dataset
boolean	initializeDataset() Invokes the initialization of the dataset.
boolean	isAvailable() A check to see if the dataset is available
boolean	isDataAvailable() This polls the dataset to see if data is available for consumption.
boolean	isInitialized() Check to see if the dataset has been initialized
boolean	supportsDataAvailabilityNotifications() Indicates whether this dataset supports dynamic data availability notifications

Methods inherited from interface ds.funnel.data.format.FormatMarshaller

marshall

Method Detail

getDatasetType

Dataset.DatasetType getDatasetType()

Retrieve the type of the data set

Returns:

type of the dataset

getDescription

java.lang.String getDescription()

Retrieve a description of the dataset

Returns:

A description of the dataset.

getIdentifier

java.lang.String getIdentifier()

Retrieve the identifier for this dataset. This would typically be a UUID which uniquely identifies the dataset in question.

Returns:

The unique identifier for this dataset.

isInitialized

boolean isInitialized()

Check to see if the dataset has been initialized

Returns:

true if the dataset is initialized; false otherwise.

initializeDataset

boolean initializeDataset()
                   throws DatasetException

Invokes the initialization of the dataset. This is invoked only when the node is ready to execute the operation that will operate on this dataset.

Returns:

true if the dataset has been initialized; false otherwise.

Throws:

DatasetException

isAvailable

boolean isAvailable()

A check to see if the dataset is available

Returns:

true if the dataset is available; false otherwise.

isDataAvailable

boolean isDataAvailable()

This polls the dataset to see if data is available for consumption.

Returns:

true if data is available on this dataset; false otherwise.

Throws:

DatasetException

getLastModificationTime

long getLastModificationTime()

Retrieve the last update to this dataset

Returns:

The time at which this dataset was last updated. The time is returned in milliseconds.

supportsDataAvailabilityNotifications

boolean supportsDataAvailabilityNotifications()

Indicates whether this dataset supports dynamic data availability notifications

Returns:

true if this dataset supports data availability notifications;false otherwise.

getDataAvailabilityNotifier

DataAvailabilityNotifier getDataAvailabilityNotifier()

Retrieve the data availability notifier for this dataset. This method will return a NULL if the underlying dataset does not support availability notifications.

Returns:

The data availability notifier for this dataset.

close

boolean close()
       throws DatasetException

Close access to this dataset. This method returns true if a graceful closure of the dataset was possible. This method will try its best to close the dataset. If it fails to close the dataset an exception, outlining the problems that were encountered will, be thrown.

Returns:

true if a graceful closure of this dataset was performed;false otherwise.

Throws:

DatasetException