uk.ac.starlink.topcat.activate

Class Downloader<T>

java.lang.Object

uk.ac.starlink.topcat.activate.Downloader<T>

public class Downloader<T>
extends Object

Manages download of data that may be required in multiple places.

Since:

24 Oct 2019

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
Downloader(String dataDescription, java.util.concurrent.Callable<T> supplier) Constructor.

Method Summary

Modifier and Type	Method and Description
void	addActionListener(ActionListener l) Adds a listener that will be notified when the data has become available.
T	getData() Immediately returns the downloaded data, or null if it has not been downloaded, or if a download has failed.
void	removeActionListener(ActionListener l) Removes a listener previously added.
void	start() Ensures that this downloader has started to downloading the data.

Methods inherited from class java.lang.Object

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

Constructor Detail

Downloader

public Downloader(String dataDescription,
                  java.util.concurrent.Callable<T> supplier)

Constructor.

Parameters:

dataDescription - short description of downloaded data, may be used in logging messages

supplier - supplier of downloaded data

Method Detail

start

public void start()

Ensures that this downloader has started to downloading the data. If it has already started (and possibly finished), this has no effect.

getData

public T getData()

Immediately returns the downloaded data, or null if it has not been downloaded, or if a download has failed.

Returns:

downloaded result, or null

addActionListener

public void addActionListener(ActionListener l)

Adds a listener that will be notified when the data has become available.

Parameters:

l - listener

removeActionListener

public void removeActionListener(ActionListener l)

Removes a listener previously added.

Parameters:

l - listener