public final class PriorityDataSource extends java.lang.Object implements DataSource
DataSource that can be used as part of a task registered with a
PriorityTaskManager.
Calls to open(DataSpec) and read(byte[], int, int) are allowed to proceed only
if there are no higher priority tasks registered to the PriorityTaskManager. If there
exists a higher priority task then PriorityTaskManager.PriorityTooLowException is thrown.
Instances of this class are intended to be used as parts of (possibly larger) tasks that are
registered with the PriorityTaskManager, and hence do not register as tasks
themselves.
DataSource.Factory| Constructor and Description |
|---|
PriorityDataSource(DataSource upstream,
PriorityTaskManager priorityTaskManager,
int priority) |
| Modifier and Type | Method and Description |
|---|---|
void |
close()
Closes the source.
|
android.net.Uri |
getUri()
When the source is open, returns the
Uri from which data is being read. |
long |
open(DataSpec dataSpec)
Opens the source to read the specified data.
|
int |
read(byte[] buffer,
int offset,
int max)
Reads up to
length bytes of data and stores them into buffer, starting at
index offset. |
public PriorityDataSource(DataSource upstream, PriorityTaskManager priorityTaskManager, int priority)
upstream - The upstream DataSource.priorityTaskManager - The priority manager to which the task is registered.priority - The priority of the task.public long open(DataSpec dataSpec) throws java.io.IOException
DataSource
Note: If an IOException is thrown, callers must still call DataSource.close() to ensure
that any partial effects of the invocation are cleaned up.
open in interface DataSourcedataSpec - Defines the data to be read.DataSpec.length equals C.LENGTH_UNSET) this value
is the resolved length of the request, or C.LENGTH_UNSET if the length is still
unresolved. For all other requests, the value returned will be equal to the request's
DataSpec.length.java.io.IOException - If an error occurs opening the source. DataSourceException can be
thrown or used as a cause of the thrown exception to specify the reason of the error.public int read(byte[] buffer,
int offset,
int max)
throws java.io.IOException
DataSourcelength bytes of data and stores them into buffer, starting at
index offset.
If length is zero then 0 is returned. Otherwise, if no data is available because the
end of the opened range has been reached, then C.RESULT_END_OF_INPUT is returned.
Otherwise, the call will block until at least one byte of data has been read and the number of
bytes read is returned.
read in interface DataSourcebuffer - The buffer into which the read data should be stored.offset - The start offset into buffer at which data should be written.max - The maximum number of bytes to read.C.RESULT_END_OF_INPUT if no data is available
because the end of the opened range has been reached.java.io.IOException - If an error occurs reading from the source.public android.net.Uri getUri()
DataSourceUri from which data is being read. The returned
Uri will be identical to the one passed DataSource.open(DataSpec) in the DataSpec
unless redirection has occurred. If redirection has occurred, the Uri after redirection
is returned.getUri in interface DataSourceUri from which data is being read, or null if the source is not open.public void close()
throws java.io.IOException
DataSource
Note: This method must be called even if the corresponding call to DataSource.open(DataSpec)
threw an IOException. See DataSource.open(DataSpec) for more details.
close in interface DataSourcejava.io.IOException - If an error occurs closing the source.