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java.lang.Object | +----javax.media.Manager
Manager is the access point for obtaining
system dependent resources such as Players,
DataSources, and the system TimeBase.
A Player is an object used to
control and render multimedia data that
is specific to the content type of the data.
A DataSource is an object used to
deliver time-based multimedia data that is specific
to a delivery protocol.
A DataSource provides
a Player with media data;
a Player must have a DataSource.
Manager provides access to a protocol and media independent
mechanism for constructing Players and
DataSources.
Manager will createPlayers from a
URL, a MediaLocator or a DataSource.
Creating a Player requires the following:
DataSource for the specified
protocol
Player for the content-type
specified by the DataSource
DataSource to the Player
using the setSource method.
MediaLocator defines a protocol for obtaining
content.
DataSources are identified by the protocol
that they support. Manager uses the protocol
name to find DataSource classes.
To find a DataSource using a MediaLocator,
Manager constructs a list of class names from the protocol
package-prefix list and the protocol name obtained
from the MediaLocator.
For each class name in the constructed list a new DataSource
is instanced, the MediaLocator is attached,
and the DataSource is connected.
If no errors have occurred, the procces is considered finished and the
connected DataSource is used by
Manager in any following operations.
If there was an error then the next class name in the list
is tried.
The exact details of the search algorithm is described in
the method documentation below.
Player is a MediaHandler.
A MediaHandler is a an object that reads
data from a DataSource. There are two types
of supported MediaHandler: MediaProxy,
and Player.
MediaHandlers are identified by the content type that they
support. A DataSource identifies the content type
of the data it produces with the getContentType method.
Manager uses the content type name to
find instances of MediaHandler.
To find a
If the
If the
If a valid
The detailed creation algorithm is specified in the methods below.
The algorithm for creating a
The algorithm for creating a
Returns a data source for the protocol specified by
the
The algorithm for creating a
The first name in the list will always be:
Each additional name looks like:
The first name in the list will always be:
Each additional name looks like:
MediaHandler using a content type name,
Manager constructs a list of class names from
the content package-prefix list and the content type name.
For each class name in the constructed list a new MediaHandler
is instanced, and the DataSource is attached to
the MediaHandler using MediaHandler is a Player and the
setSource was successful the process is finished
and the Player is returned.
If the setSource failed, another name in the
list is tried.
MediaHandler is a MediaProxy
then a new DataSource is obtained from the
MediaProxy, a new list is created for the
content type the DataSource supports and the
whole thing is tried again.
Player, is not found then the whole
procedure is repeated is repeated with "unknown" substituted
for the content-type name. The "unknown" content type is supported
by generic Players that are capable of handling
a large variety of media types, often in a platform dependent
way.
Player Threads
Players render media data asynchronously from
the main program flow.
This implies that a Player must often manage one
or more threads.
The threads managed by the Player are not
in the thread group of the application that calls
createPlayer.
System Time Base
All Players need a TimeBase. Many
use a system-wide TimeBase, often based on
a time-of-day clock.
Manager provides access to the system TimeBase
through getSystemTimeBase.
createDataSource(MediaLocator)
DataSource for the specified media.
createDataSource(URL)
DataSource for the specified media.
createPlayer(DataSource)
Player for the DataSource.
createPlayer(MediaLocator)
Player for the specified media.
createPlayer(URL)
Player for the specified media.
getDataSourceList(String)
DataSource class names from the
protocol prefix-list and a protocol name.
getHandlerClassList(String)
Handler/CODE> classes from the
content-prefix-list and a content name.
getSystemTimeBase()
UNKNOWN_CONTENT_NAME
public static final String UNKNOWN_CONTENT_NAME
createPlayer
public static Player createPlayer(URL sourceURL) throws IOException, NoPlayerException
Player for the specified media.
This creates a MediaLocator from the URL and then
calls createPlayer.
URL that describes the media data.
Player.
Player
can be found.
createPlayer
public static Player createPlayer(MediaLocator sourceLocator) throws IOException, NoPlayerException
Player for the specified media.
Player from
a MediaLocator is:
MediaLocator.
DataSource classes that
support the protocol, using the protocol package-prefix-list.
DataSource,
connect method to connect the source.
getContentType)
from the source.
MediaHandler classes that support the
media-content-type-name, using the content package-prefix-list.
MediaHandler class in the list:
MediaHandler.
MediaHandler by calling
MediaHandler.setSource.
MediaHandler; otherwise try the next
MediaHandler is a Player,
return the new Player.
MediaHandler is a MediaProxy,
obtain a new DataSource from the MediaProxy,
obtain the list of MediaHandlers that support the new
DataSource, and continue searching the new list.
MediaHandler is found for this source,
try the next source in the list.
Player is found after trying all of the sources,
reuse the source list.
This time, for each source class in the list:
connect method to connect to the source.
MediaHandler classes that support the
"unknown" content-type-name.
MediaHandler class in the list,
search for a Player as in the previous search.
Player is found after trying all of the sources,
a NoPlayerException is thrown.
MediaLocator that describes
the media content.
Player for the media described by the source.
Player can
be found.
createPlayer
public static Player createPlayer(DataSource source) throws IOException, NoPlayerException
Player for the DataSource.
Player from
a DataSource is:
getContentType.
Player classes that support the media content-type name.
Player class in the list:
Player.
Player by calling
setSource on the Player.
Player;
otherwise,
try the next Player in the list.
Player is found for this source:
Player classes that support the
"unknown" content-type-name.
Player class in the list:
Player.
Player by
calling setSource
on the Player.
Player;
otherwise, try the next Player in the list.
Player can be created,
a NoPlayerException is thrown.
DataSource that describes
the media content.
Player.
Player can't
be created.
createDataSource
public static DataSource createDataSource(URL sourceURL) throws IOException, NoDataSourceException
DataSource for the specified media.
URL that describes the media data.
DataSource for the media.
DataSource
can be found.
createDataSource
public static DataSource createDataSource(MediaLocator sourceLocator) throws IOException, NoDataSourceException
DataSource for the specified media.
MediaLocator. The returned data source
is connected; DataSource.connect has been
invoked.
DataSource from
a MediaLocator is:
MediaLocator.
DataSource classes that
support the protocol.
DataSource.
connect to connect the source.
URL from the
MediaLocator and use it to create
a URLDataSource
NoDataSourceException
is thrown.
DataSource.
DataSource
can be found.
getSystemTimeBase
public static TimeBase getSystemTimeBase()
getDataSourceList
public static Vector getDataSourceList(String protocolName)
DataSource class names from the
protocol prefix-list and a protocol name.
media.protocol.<protocol>DataSource
for every
<protocol-prefix>.media.protocol.<protocol>.DataSource
<protocol-prefix> in the
protocol-prefix-list.
Player class-name.
getHandlerClassList
public static Vector getHandlerClassList(String contentName)
Handler/CODE> classes from the
content-prefix-list and a content name.
media.content.<contentType>.Handler
for every
<content-prefix>.media.content.<contentName>.Player
<content-prefix> in the
content-prefix-list.
Player
class-name.
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