Package ca.corbett.extras.io

Class DownloadManager

java.lang.Object

ca.corbett.extras.io.DownloadManager

public class DownloadManager
extends Object

Manages file downloads via http and reports on their progress, completion status, or error status. You could of course just manually instantiate DownloadThread instances and fire them off, but this manager class creates and owns a single, reusable, thread-safe HttpClient that makes launching multiple download requests much cleaner. It also keeps track of downloads in progress so that we can offer methods like isDownloadInProgress() and stopAllDownloads().

Since:

swing-extras 2.5

Author:

scorbo2

Field Summary

Fields

Modifier and Type	Field	Description
static final int	CONNECTION_TIMEOUT_SECONDS
static final int	DOWNLOAD_TIMEOUT_SECONDS

Constructor Summary

Constructors

Constructor	Description
DownloadManager()

Method Summary

Modifier and Type	Method	Description
void	close()	Closes the HTTP client.
DownloadThread	createDownloadThread(URL url, File targetDir, DownloadListener listener)	Creates and returns a DownloadThread suitable for executing the given download.
void	downloadFile(URL url, DownloadListener listener)	Downloads a file from the given URL and saves it in the system temp directory.
void	downloadFile(URL url, File targetDir, DownloadListener listener)	Downloads a file from the given URL and saves it to the specified path.
static String	getFileExtension(String filename)	If the given String represents a filename with an extension, this will return the final dot character and the extension.
static String	getFilenameComponent(String path)	Looks for the last / character in the given path string and returns everything after it.
boolean	isDownloadInProgress()	Returns true if at least one download is currently running.
void	stopAllDownloads()	Sends a kill() request to all active download threads.

Methods inherited from class java.lang.Object

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

Field Details

CONNECTION_TIMEOUT_SECONDS

public static final int CONNECTION_TIMEOUT_SECONDS

See Also:

• Constant Field Values

DOWNLOAD_TIMEOUT_SECONDS

public static final int DOWNLOAD_TIMEOUT_SECONDS

See Also:

• Constant Field Values

Constructor Details

DownloadManager

public DownloadManager()

Method Details

downloadFile

public void downloadFile(URL url,
 DownloadListener listener)

Downloads a file from the given URL and saves it in the system temp directory.

downloadFile

public void downloadFile(URL url,
 File targetDir,
 DownloadListener listener)

Downloads a file from the given URL and saves it to the specified path.

Parameters:

url - The URL to download from (supported protocols: http, https, file)

targetDir - Where to save the file

listener - An optional DownloadListener to receive progress/failure/completion notifications.

isDownloadInProgress

public boolean isDownloadInProgress()

Returns true if at least one download is currently running.

stopAllDownloads

public void stopAllDownloads()

Sends a kill() request to all active download threads. Does not guarantee that they will stop immediately. Any download currently in progress will report a download failure.

createDownloadThread

public DownloadThread createDownloadThread(URL url,
 File targetDir,
 DownloadListener listener)

Creates and returns a DownloadThread suitable for executing the given download. You can use the downloadFile() wrapper method instead, to both create and automatically start the thread.

close

public void close()

Closes the HTTP client.

getFileExtension

public static String getFileExtension(String filename)

If the given String represents a filename with an extension, this will return the final dot character and the extension. Otherwise, an empty string is returned. Examples:

• getFileExtension("hello.txt"); // returns ".txt"
• getFileExtension("hello.txt.jpg"); // returns ".jpg"
• getFileExtension("That. Does not make sense"); // returns ". Does not make sense"
• getFileExtension("hello"); // returns ""

getFilenameComponent

public static String getFilenameComponent(String path)

Looks for the last / character in the given path string and returns everything after it. This can be used for URLs or for linux-style filesystem paths. Examples:

• getFilenameComponent("/path/to/file.txt"); // returns "file.txt"
• getFilenameComponent("no slash character"); // returns ""
• getFilenameComponent("/slash/at/end/"); // return ""