public final class FileDataSource extends Object implements UriDataSource
UriDataSource
.Modifier and Type | Class and Description |
---|---|
static class |
FileDataSource.FileDataSourceException
Thrown when IOException is encountered during local file read operation.
|
Constructor and Description |
---|
FileDataSource()
Constructs a new
DataSource that retrieves data from a file. |
FileDataSource(TransferListener listener)
Constructs a new
DataSource that retrieves data from a file. |
Modifier and Type | Method and Description |
---|---|
void |
close()
Closes the
DataSource . |
String |
getUri()
When the source is open, returns the URI from which data is being read.
|
long |
open(DataSpec dataSpec)
Opens the
DataSource to read the specified data. |
int |
read(byte[] buffer,
int offset,
int readLength)
Reads up to
length bytes of data and stores them into buffer , starting at
index offset . |
public FileDataSource()
DataSource
that retrieves data from a file.public FileDataSource(TransferListener listener)
DataSource
that retrieves data from a file.listener
- An optional listener. Specify null
for no listener.public long open(DataSpec dataSpec) throws FileDataSource.FileDataSourceException
DataSource
DataSource
to read the specified data. Calls to DataSource.open(DataSpec)
and
DataSource.close()
must be balanced.
Note: If DataSource.open(DataSpec)
throws an IOException
, callers must still call
DataSource.close()
to ensure that any partial effects of the DataSource.open(DataSpec)
invocation
are cleaned up. Implementations of this class can assume that callers will call
DataSource.close()
in this case.
open
in interface DataSource
dataSpec
- Defines the data to be read.DataSpec.length
equals C.LENGTH_UNBOUNDED
) this value
is the resolved length of the request, or C.LENGTH_UNBOUNDED
if the length is still
unresolved. For all other requests, the value returned will be equal to the request's
DataSpec.length
.FileDataSource.FileDataSourceException
public int read(byte[] buffer, int offset, int readLength) throws FileDataSource.FileDataSourceException
DataSource
length
bytes of data and stores them into buffer
, starting at
index offset
.
This method blocks until at least one byte of data can be read, the end of the opened range is detected, or an exception is thrown.
read
in interface DataSource
buffer
- The buffer into which the read data should be stored.offset
- The start offset into buffer
at which data should be written.readLength
- The maximum number of bytes to read.C.RESULT_END_OF_INPUT
if the end of the opened
range is reached.FileDataSource.FileDataSourceException
public String getUri()
UriDataSource
If redirection occurred, the URI after redirection is the one returned.
getUri
in interface UriDataSource
public void close() throws FileDataSource.FileDataSourceException
DataSource
DataSource
.
Note: This method will be called even if the corresponding call to DataSource.open(DataSpec)
threw an IOException
. See DataSource.open(DataSpec)
for more details.
close
in interface DataSource
FileDataSource.FileDataSourceException