PriorityDataSource
@UnstableApi
class PriorityDataSource : DataSource
A DataSource that can be used as part of a task registered with a PriorityTaskManager.
Calls to open and read 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.
Summary
Nested types |
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Public constructors |
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PriorityDataSource( |
Public functions |
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Unit |
addTransferListener(transferListener: TransferListener!)Adds a |
Unit |
close()Closes the source. |
(Mutable)Map<String!, (Mutable)List<String!>!>! |
When the source is open, returns the response headers associated with the last |
Uri? |
getUri()When the source is open, returns the |
Long |
Opens the source to read the specified data. |
Int |
Reads up to |
Public constructors
PriorityDataSource
PriorityDataSource(
upstream: DataSource!,
priorityTaskManager: PriorityTaskManager!,
@C.Priority priority: Int
)
| Parameters | |
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upstream: DataSource! |
The upstream |
priorityTaskManager: PriorityTaskManager! |
The priority manager to which the task is registered. |
@C.Priority priority: Int |
The |
Public functions
addTransferListener
fun addTransferListener(transferListener: TransferListener!): Unit
Adds a TransferListener to listen to data transfers. This method is not thread-safe.
| Parameters | |
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transferListener: TransferListener! |
close
fun close(): Unit
Closes the source. This method must be called even if the corresponding call to open threw an IOException.
| Throws | |
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java.io.IOException |
If an error occurs closing the source. |
getResponseHeaders
fun getResponseHeaders(): (Mutable)Map<String!, (Mutable)List<String!>!>!
When the source is open, returns the response headers associated with the last open call. Otherwise, returns an empty map.
Key look-up in the returned map is case-insensitive.
getUri
fun getUri(): Uri?
When the source is open, returns the Uri from which data is being read. The returned Uri will be identical to the one passed open in the DataSpec unless redirection has occurred. If redirection has occurred, the Uri after redirection is returned.
open
fun open(dataSpec: DataSpec!): Long
Opens the source to read the specified data. If an IOException is thrown, callers must still call close to ensure that any partial effects of the invocation are cleaned up.
The following edge case behaviors apply:
- If the
requested positionis within the resource, but therequested lengthextends beyond the end of the resource, thenopenwill succeed and data from the requested position to the end of the resource will be made available throughread. - If the
requested positionis equal to the length of the resource, thenopenwill succeed, andreadwill immediately returnRESULT_END_OF_INPUT. - If the
requested positionis greater than the length of the resource, thenopenwill throw anIOExceptionfor whichisCausedByPositionOutOfRangewill betrue.
| Parameters | |
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dataSpec: DataSpec! |
Defines the data to be read. |
| Returns | |
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Long |
The number of bytes that can be read from the opened source. For unbounded requests (i.e., requests where |
| Throws | |
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java.io.IOException |
If an error occurs opening the source. |
read
fun read(buffer: ByteArray!, offset: Int, length: Int): Int
Reads up to length bytes of data from the input.
If readLength is zero then 0 is returned. Otherwise, if no data is available because the end of the opened range has been reached, then 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.
| Parameters | |
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buffer: ByteArray! |
A target array into which data should be written. |
offset: Int |
The offset into the target array at which to write. |
length: Int |
The maximum number of bytes to read from the input. |
| Returns | |
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Int |
The number of bytes read, or |
| Throws | |
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java.io.IOException |
If an error occurs reading from the input. |