PlaceholderDataSource

Artifact: androidx.media3:media3-datasource

Kotlin |Java

@UnstableApi
public final class PlaceholderDataSource implements DataSource

A DataSource which provides no data. open throws IOException.

Summary

Constants
`static final DataSource.Factory`	`FACTORY` A factory that produces `PlaceholderDataSource`.
`static final PlaceholderDataSource`	`INSTANCE`

Public methods
`void`	`addTransferListener(TransferListener transferListener)` Adds a `TransferListener` to listen to data transfers.
`void`	`close()` Closes the source.
`@Nullable 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 length)` Reads up to `length` bytes of data from the input.

Inherited methods

From androidx.media3.datasource.DataSource

Map<String, List<String>>

@UnstableApi
getResponseHeaders()

When the source is open, returns the response headers associated with the last open call.

Constants

FACTORY

public static final DataSource.Factory FACTORY

A factory that produces PlaceholderDataSource.

INSTANCE

public static final PlaceholderDataSource INSTANCE

Public methods

addTransferListener

public void addTransferListener(TransferListener transferListener)

Adds a TransferListener to listen to data transfers. This method is not thread-safe.

Parameters
`TransferListener transferListener`	A `TransferListener`.

close

public void close()

Closes the source. This method must be called even if the corresponding call to open threw an IOException.

Throws
`java.io.IOException`	If an error occurs closing the source.

getUri

public @Nullable Uri getUri()

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.

Returns
`@Nullable Uri`	The `Uri` from which data is being read, or null if the source is not open.

open

public long open(DataSpec dataSpec)

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 position is within the resource, but the requested length extends beyond the end of the resource, then open will succeed and data from the requested position to the end of the resource will be made available through read.
If the requested position is equal to the length of the resource, then open will succeed, and read will immediately return RESULT_END_OF_INPUT.
If the requested position is greater than the length of the resource, then open will throw an IOException for which isCausedByPositionOutOfRange will be true.

Parameters
`DataSpec dataSpec`	Defines the data to be read.

Returns
`long`	The number of bytes that can be read from the opened source. For unbounded requests (i.e., requests where `length` equals `LENGTH_UNSET`) this value is the resolved length of the request, or `LENGTH_UNSET` if the length is still unresolved. For all other requests, the value returned will be equal to the request's `length`.

Throws
`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.

read

public int read(byte[] buffer, int offset, int length)

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
`byte[] buffer`	A target array into which data should be written.
`int offset`	The offset into the target array at which to write.
`int length`	The maximum number of bytes to read from the input.

Returns
`int`	The number of bytes read, or `RESULT_END_OF_INPUT` if the input has ended. This may be less than `length` because the end of the input (or available data) was reached, the method was interrupted, or the operation was aborted early for another reason.

Throws
`java.io.IOException`	If an error occurs reading from the input.