de.aitools.aq.webdownload
Class Downloader

java.lang.Object
  de.aitools.aq.webdownload.Downloader

Direct Known Subclasses:

WgetDownloader

public abstract class Downloader
extends java.lang.Object

Downloader is the abstract base class for all Downloaders.

Author:

christof.braeutigam@uni-weimar.de

Method Summary

java.lang.String	getContentType(java.lang.String url) Returns the data of the Content-Type HTTP response header field for the given url or null if no such field exists.
java.lang.String	getContentType(java.net.URL url) Returns the data of the Content-Type HTTP response header field for the given url or null if no such field exists.
java.util.Map<java.lang.String,java.util.List<java.lang.String>>	getHeaders(java.lang.String url) Convenience method to detect the content type of the resource designated by url.
int	getReadTimeout()
java.lang.String	getTempFilePrefix()
java.lang.String	getTempFileSuffix()
abstract java.io.File	load(java.lang.String url) Loads the data designated by url and creates and returns a file object which can be used to access the data.
abstract java.io.File	load(java.lang.String url, java.io.File dir) Loads the data designated by url to the directory designated by dir.
abstract java.io.File	load(java.net.URL url) Loads the data designated by url and creates and returns a file object which can be used to access the data.
abstract java.io.File	load(java.net.URL url, java.io.File dir) Loads the data designated by url to the directory designated by dir.
int	setConnectionTimeout()
void	setConnectionTimeout(int seconds)
void	setReadTimeout(int seconds)
void	setTempFilePrefix(java.lang.String tempFilePrefix)
void	setTempFileSuffix(java.lang.String tempFileSuffix)

Methods inherited from class java.lang.Object

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

Method Detail

load

public abstract java.io.File load(java.lang.String url)
                           throws DownloaderException

Loads the data designated by url and creates and returns a file object which can be used to access the data.

Parameters:

url - The resource to download

Returns:

A File to access the downloaded data

Throws:

DownloaderException

load

public abstract java.io.File load(java.net.URL url)
                           throws DownloaderException

Loads the data designated by url and creates and returns a file object which can be used to access the data.

Parameters:

url - The resource to download

Returns:

A File to access the downloaded data

Throws:

DownloaderException

load

public abstract java.io.File load(java.lang.String url,
                                  java.io.File dir)
                           throws DownloaderException

Loads the data designated by url to the directory designated by dir. A file is created in dir and will be returned to provide access to the downloaded data.

Note that the provided dir must denote a directory and this directory must be writable.

Parameters:

url - The resource to download

dir - The directory where the downloaded data should be stored

Returns:

A File to access the downloaded data

Throws:

DownloaderException

load

public abstract java.io.File load(java.net.URL url,
                                  java.io.File dir)
                           throws DownloaderException

Loads the data designated by url to the directory designated by dir. A file is created in dir and will be returned to provide access to the downloaded data.

Note that the provided dir must denote a directory and this directory must be writable.

Parameters:

url - The resource to download

dir - The directory where the downloaded data should be stored

Returns:

A File to access the downloaded data

Throws:

DownloaderException

setConnectionTimeout

public void setConnectionTimeout(int seconds)

setConnectionTimeout

public int setConnectionTimeout()

setReadTimeout

public void setReadTimeout(int seconds)

getReadTimeout

public int getReadTimeout()

setTempFilePrefix

public void setTempFilePrefix(java.lang.String tempFilePrefix)

getTempFilePrefix

public java.lang.String getTempFilePrefix()

setTempFileSuffix

public void setTempFileSuffix(java.lang.String tempFileSuffix)

getTempFileSuffix

public java.lang.String getTempFileSuffix()

getHeaders

public java.util.Map<java.lang.String,java.util.List<java.lang.String>> getHeaders(java.lang.String url)
                                                                            throws DownloaderException

Convenience method to detect the content type of the resource designated by url. In fact this just opens an URLConnection and returns the output of getContentType().

Note that this method will return null in several cases, e.g.:

• if no content type information is available
• if the resource designated by url doesn't exist
• if a network or connection error occurs
• ...

Parameters:

url - The resource whose content type should be detected

Returns:

A String containing the content type (most likely in the form of a mime-type or null if no content type information is available.

Throws:

DownloaderException

getContentType

public java.lang.String getContentType(java.lang.String url)
                                throws DownloaderException

Returns the data of the Content-Type HTTP response header field for the given url or null if no such field exists. Note that this method doesn't follows HTTP 30X redirects.

Parameters:

url - The url for which the content type should be returned.

Returns:

The content type as it is retrieved from the HTTP response header

Throws:

DownloaderException

getContentType

public java.lang.String getContentType(java.net.URL url)
                                throws DownloaderException

Returns the data of the Content-Type HTTP response header field for the given url or null if no such field exists. Note that this method doesn't follows HTTP 30X redirects.

Parameters:

url - The url for which the content type should be returned.

Returns:

The content type as it is retrieved from the HTTP response header

Throws:

DownloaderException