FileDataSource (libmedia API Specification)

java.lang.Object
- fr.maxcom.http.FileDataSource

All Implemented Interfaces:

DataSource
```
public class FileDataSource
extends Object
implements DataSource
```
The default implementation for a data provider that obtains its content from a file, or more generally from a resource. It supports encrypted files if a Cipher is provided.
An instance is used by the server, unless another custom object is provided with HttpServer.setDataSource(DataSource).

If decryption is needed, use HttpServer.setCipher(Cipher) or HttpServer.setCipherFactory(CipherFactory) to communicate a cipher to the data source.

Constructor Summary

Constructors
Constructor and Description

FileDataSource()

Constructors
Constructor and Description
`FileDataSource()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`long`	`getContentLength()` Returns the length of data to deliver, that is the length of the file minus the offset, unless a cipher with a padding scheme is used.
`long`	`getContentSize()` Returns the length of the file, unless a cipher with a padding scheme is used.
`String`	`getContentType()` Returns the content type of the file.
`InputStream`	`getInputStream()` Returns a content stream of the resource.
`long`	`getOffset()` Returns the offset in the file.
`String`	`getUriString()` Returns the URI of the data source.
`boolean`	`isExisting()` Tests whether the file exists.
`boolean`	`isPartial()` Tells whether the content to be delivered will be partial.
`boolean`	`isReadable()` Tests whether the file can be read.
`void`	`setCipher(Cipher cipher)` Sets the `Cipher` to use if the stream has to be decrypted.
`void`	`setCipherFactory(CipherFactory cipherFactory)` Sets the factory instance, able to deliver ciphers when needed.
`void`	`setSource(URI uri, long offset)` Sets the properties of the data source.
`protected InputStream`	`toInputStream(AssetFileDescriptor afd)` A internal step called in `getInputStream()` to get a stream out of the file.
`protected InputStream`	`toInputStream(File file)` A internal step called in `getInputStream()` to get a stream out of the file.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - FileDataSource
```
public FileDataSource()
```
- Method Detail
  - setCipher
```
public void setCipher(Cipher cipher)
```
    Description copied from interface: DataSource
    
    Sets the Cipher to use if the stream has to be decrypted. The information may also be set through HttpServer.setCipher(Cipher).
    
    Specified by:
    
    setCipher in interface DataSource
    
    Parameters:
    
    cipher - The cipher needed to decrypt the stream.
  - setCipherFactory
```
public void setCipherFactory(CipherFactory cipherFactory)
```
    Description copied from interface: DataSource
    
    Sets the factory instance, able to deliver ciphers when needed. The information may also be set through HttpServer.setCipherFactory(CipherFactory).
    
    Specified by:
    
    setCipherFactory in interface DataSource
    
    Parameters:
    
    cipherFactory - The factory to deliver ciphers on demand.
  - setSource
```
public void setSource(URI uri,
                      long offset)
```
    Sets the properties of the data source. The URI is interpreted as either:
    - an absolute path to a regular file
    - an entry into a Zip file specified by an absolute path
    - an entry into an APK Expansion File
    - a wrapper for an asset file
    - a wrapper for an SMB url
    - a wrapper for a HTTP[S] url
    - a wrapper for a FTP url
    Specified by:
    
    setSource in interface DataSource
    
    Parameters:
    
    uri - The URI as provided in the HTTP request line.
    
    offset - The offset provided in a Range request header, or 0 by default.
  - getUriString
```
public String getUriString()
```
    Description copied from interface: DataSource
    
    Returns the URI of the data source. Mainly designed for the build of reporting messages.
    
    Specified by:
    
    getUriString in interface DataSource
    
    Returns:
    
    The string form of the URI, or null if called before setSource() by mistake.
  - isExisting
```
public boolean isExisting()
```
    Tests whether the file exists.
    
    Specified by:
    
    isExisting in interface DataSource
    
    Returns:
    
    true if and only if the resource really exists.
  - isReadable
```
public boolean isReadable()
```
    Tests whether the file can be read. The declared file must be: existent, readable, normal (not a directory), and not hidden. In the case of an entry in a Zip file, it must not be compressed.
    
    Specified by:
    
    isReadable in interface DataSource
    
    Returns:
    
    true if and only if the resource can be accessed for reading.
  - toInputStream
```
protected InputStream toInputStream(File file)
                             throws FileNotFoundException
```
    A internal step called in getInputStream() to get a stream out of the file. It is mainly designed for debugging: overriding only this method is enough to get a hook on the flow, and still benefit from the implemented features (decryption, offset management).
    
    Parameters:
    
    file - The file to get a stream from.
    
    Returns:
    
    A content stream.
    
    Throws:
    
    FileNotFoundException - If the file does not exist.
  - toInputStream
```
protected InputStream toInputStream(AssetFileDescriptor afd)
                             throws IOException
```
    A internal step called in getInputStream() to get a stream out of the file. It is mainly designed for debugging: overriding only this method is enough to get a hook on the flow, and still benefit from the implemented features (decryption, offset management).
    
    Parameters:
    
    afd - The file descriptor of the Zip or Asset entry to get a stream from.
    
    Returns:
    
    A content stream.
    
    Throws:
    
    IOException - If the stream cannot be created.
  - getInputStream
```
public InputStream getInputStream()
                           throws IOException
```
    Description copied from interface: DataSource
    
    Returns a content stream of the resource.
    
    Specified by:
    
    getInputStream in interface DataSource
    
    Returns:
    
    A content stream.
    
    Throws:
    
    IOException - If the stream cannot be created or skipped, or if some other I/O error occurs.
  - isPartial
```
public boolean isPartial()
```
    Description copied from interface: DataSource
    
    Tells whether the content to be delivered will be partial. This should be the case when a non zero offset is set.
    
    Specified by:
    
    isPartial in interface DataSource
    
    Returns:
    
    true if the content to deliver is only a part of the full resource.
  - getContentSize
```
public long getContentSize()
```
    Returns the length of the file, unless a cipher with a padding scheme is used. With padding, the file size is not a piece of information to rely on to know the total length of the resource content.
    
    Specified by:
    
    getContentSize in interface DataSource
    
    Returns:
    
    A number of bytes, or a negative number if unknown.
  - getOffset
```
public long getOffset()
```
    Returns the offset in the file.
    
    Specified by:
    
    getOffset in interface DataSource
    
    Returns:
    
    The number of first bytes of data to skip before to stream the content.
  - getContentLength
```
public long getContentLength()
```
    Returns the length of data to deliver, that is the length of the file minus the offset, unless a cipher with a padding scheme is used. With padding, the file size is not a piece of information to rely on to know the total length of the resource content.
    
    Specified by:
    
    getContentLength in interface DataSource
    
    Returns:
    
    A number of bytes, or a negative number if unknown.
  - getContentType
```
public String getContentType()
```
    Returns the content type of the file. The type is determined according to, in priority:
    - The response of the remote http server, if applicable
    - The filename extension
    Example: for a mp4 file, returns "video/mp4".
    Specified by:
    
    getContentType in interface DataSource
    
    Returns:
    
    The content type, or null if the type is unknown.

Class FileDataSource

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

FileDataSource

Method Detail

setCipher

setCipherFactory

setSource

getUriString

isExisting

isReadable

toInputStream

toInputStream

getInputStream

isPartial

getContentSize

getOffset

getContentLength

getContentType