javax.media
类 Manager

java.lang.Object
  javax.media.Manager

public final class Manager
extends java.lang.Object

Manager is the access point for obtaining system dependent resources such as Players, DataSources, Processors, DataSinks, the system TimeBase, the cloneable and merging utility DataSources.

A DataSource is an object used to deliver time-based multimedia data that is specific to a delivery protocol.

A Player is an object used to control and render multimedia data that is specific to the content type of the data.

A Processor is an object similar to a Player which is used to process data and output the processed data.

A DataSink is an object that takes a DataSource as input and renders the output to a specified destination.

A DataSource provides a Player, Processor or DataSink with media data; a Player, Processor or DataSink must have a DataSource. Manager provides access to a protocol and media independent mechanism for constructing DataSources, Players, Processors and DataSinks.

Creating Players and DataSources

Manager will createPlayers from a URL, a MediaLocator or a DataSource. Creating a Player requires the following:

• Obtain the connected DataSource for the specified protocol
• Obtain the Player for the content-type specified by the DataSource
• Attach the DataSource to the Player using the setSource method.

Finding DataSources by Protocol

A 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 instantiated, 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.

Finding Players by Content Type

A Player is a MediaHandler. A MediaHandler is a an object that reads data from a DataSource. There are three types of supported MediaHandler: MediaProxy, Player and Processor.

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 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 instantiated, and the DataSource is attached to the MediaHandler using MediaHandler.setSource.

If the 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.

If the 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.

If a valid Player is not found then the whole procedure 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.

The detailed creation algorithm is specified in the methods below.

Creating a Realized Player

Versions of createRealizedPlayer calls are provided as an acceleration to create a Player. The returned player is in the Realized state. In addition to NoPlayerException and IOException, CannotRealizeException can be thrown if the Manager cannot realize the Player.

Creating Processors

Processors are created in the same way as Players as outlined above. Manager also provides an additional way to create a Processor via the createRealizedProcessor call. A ProcessorModel is used to fully identify the input and output requirements of a Processor. The createRealizedProcessor call takes a ProcessorModel as input and create a Processor that adheres to the given ProcessorModel. The returned Processor is in the Realized state. The method is a blocking call.

If the Manager fails to find a Processor that fits the ProcessorModel, a NoProcessorException is thrown. If there is a problem creating and realizing a Processor, it will throw an IOException or CannotRealizeException depending on the circumstances.

Creating DataSinks

DataSinks are created from an input DataSource MediaLocator. The MediaLocator identifies the protocol and content of the DataSink to be used. The search for the particular DataSink class to be created is similar to the process of creating a DataSource. The detail search and creation algorithm is described in the method documentation below.

Player and Processor Threads

Players and Processors process media data asynchronously from the main program flow. This implies that a Player or Processor must often manage one or more threads. The threads managed by the Player or Processor are not in the thread group of the application that calls createPlayer or createProcessor.

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.

Cloning and Merging DataSources

DataSources can be cloned or merged. If a DataSource is cloned, more than one MediaHandler can use it as input. Merging more than one DataSources will generate one DataSource which contains all the SourceStreams of the constituent DataSources

The Manager provides two methods: createCloneableDataSource and createMergingDataSource for such purpose.

Manager Hints

Using the setHint method, the preference for how the Manager creates the objects can be specified. However, a particular implementation of the Manager can choose to ignore the requested hints.

从以下版本开始：

1.0 , new methods added in 2.0

另请参见：

MAX_SECURITY, CACHING, LIGHTWEIGHT_RENDERER,

, URL, MediaLocator, PackageManager, DataSource, URLDataSource, MediaHandler, Player, Processor, MediaProxy, TimeBase

字段摘要

static int	CACHING Boolean hint to turn on/off the use of playback caching.
static int	LIGHTWEIGHT_RENDERER Boolean hint to turn on/off the use of light weight rendering.
static int	MAX_SECURITY Boolean hint to turn on/off maximum security.
static int	PLUGIN_PLAYER Boolean hint to request the Manager to create Players that support PlugIns.
static java.lang.String	UNKNOWN_CONTENT_NAME

方法摘要

static javax.media.protocol.DataSource	createCloneableDataSource(javax.media.protocol.DataSource source)
static DataSink	createDataSink(javax.media.protocol.DataSource datasource, MediaLocator destLocator) Create a DataSink for the specified input Datasource and destination Medialocator.
static javax.media.protocol.DataSource	createDataSource(MediaLocator sourceLocator) Create a DataSource for the specified media.
static javax.media.protocol.DataSource	createDataSource(java.net.URL sourceURL) Create a DataSource for the specified media.
static javax.media.protocol.DataSource	createMergingDataSource(javax.media.protocol.DataSource[] sources) Creates a merged DataSource from an array of sources.
static Player	createPlayer(javax.media.protocol.DataSource source) Create a Player for the DataSource.
static Player	createPlayer(MediaLocator sourceLocator) Create a Player for the specified media.
static Player	createPlayer(java.net.URL sourceURL) Create a Player for the specified media.
static Processor	createProcessor(javax.media.protocol.DataSource source) Create a Processor for the DataSource.
static Processor	createProcessor(MediaLocator sourceLocator) Create a Processor for the specified media.
static Processor	createProcessor(java.net.URL sourceURL) Create a Processor for the specified media.
static Player	createRealizedPlayer(javax.media.protocol.DataSource source) Create a Realized Player for the specified source.
static Player	createRealizedPlayer(MediaLocator ml) Create a Realized Player for the specified media.
static Player	createRealizedPlayer(java.net.URL sourceURL) Create a Realized Player for the specified media.
static Processor	createRealizedProcessor(ProcessorModel model) Create a Realized Processor for the specified ProcessorModel.
static java.lang.String	getCacheDirectory() Retrieve the directory that's used for playback caching.
static java.util.Vector	getDataSourceList(java.lang.String protocolName) Build a list of DataSource class names from the protocol prefix-list and a protocol name.
static java.util.Vector	getHandlerClassList(java.lang.String contentName) Build a list of Player Handler classes from the content-prefix-list and a content name.
static java.lang.Object	getHint(int hint) Retrieve the value of a hint set.
static java.util.Vector	getProcessorClassList(java.lang.String contentName) Build a list of Processor Handler classes from the content-prefix-list and a content name.
static TimeBase	getSystemTimeBase() Get the time-base object for the system.
static java.lang.String	getVersion() Returns the version string for this revision of JMF.
static void	setHint(int hint, java.lang.Object value) Specify a hint for the Manager to use.

从类 java.lang.Object 继承的方法

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细信息

MAX_SECURITY

public static final int MAX_SECURITY

Boolean hint to turn on/off maximum security.

另请参见：

常量字段值

CACHING

public static final int CACHING

Boolean hint to turn on/off the use of playback caching.

另请参见：

常量字段值

LIGHTWEIGHT_RENDERER

public static final int LIGHTWEIGHT_RENDERER

Boolean hint to turn on/off the use of light weight rendering. If on, the Manager will try to create Players that use renderers which can interoperate with light weight GUI components.

另请参见：

常量字段值

PLUGIN_PLAYER

public static final int PLUGIN_PLAYER

Boolean hint to request the Manager to create Players that support PlugIns. Such Players use PlugIns to demultiplex, decode, render or multiplex the data. It will also support TrackControls for application level programming.

另请参见：

常量字段值

UNKNOWN_CONTENT_NAME

public static final java.lang.String UNKNOWN_CONTENT_NAME

另请参见：

常量字段值

方法详细信息

getVersion

public static java.lang.String getVersion()

Returns the version string for this revision of JMF.

createPlayer

public static Player createPlayer(java.net.URL sourceURL)
                           throws java.io.IOException,
                                  NoPlayerException

Create a Player for the specified media. This creates a MediaLocator from the URL and then calls createPlayer.

参数：

sourceURL - The URL that describes the media data.

返回：

A new Player.

抛出：

NoPlayerException - Thrown if no Player can be found.

java.io.IOException - Thrown if there was a problem connecting with the source.

createPlayer

public static Player createPlayer(MediaLocator sourceLocator)
                           throws java.io.IOException,
                                  NoPlayerException

Create a Player for the specified media.

The algorithm for creating a Player from a MediaLocator is:

1. Get the protocol from the MediaLocator.
2. Get a list of DataSource classes that support the protocol, using the protocol package-prefix-list.
3. For each source class in the list:
   1. Instantiate a new DataSource,
   2. Call the connect method to connect the source.
   3. Get the media content-type-name (using getContentType) from the source.
   4. Get a list of MediaHandler classes that support the media-content-type-name, using the content package-prefix-list.
   5. For each MediaHandler class in the list:
      1. Instantiate a new MediaHandler.
      2. Attach the source to the MediaHandler by calling MediaHandler.setSource.
      3. If there are no failures, determine the type of the MediaHandler; otherwise try the next MediaHandler in the list.
      4. If the MediaHandler is a Player, return the new Player.
      5. If the 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.
   6. If no MediaHandler is found for this source, try the next source in the list.
4. If no Player is found after trying all of the sources, reuse the source list.
   This time, for each source class in the list:
   1. Instantiate the source.
   2. Call the connect method to connect to the source.
   3. Use the content package-prefix-list to create a list of MediaHandler classes that support the "unknown" content-type-name.
   4. For each MediaHandler class in the list, search for a Player as in the previous search.
      1. If no Player is found after trying all of the sources, a NoPlayerException is thrown.

   参数：

   sourceLocator - A MediaLocator that describes the media content.

   返回：

   A Player for the media described by the source.

   抛出：

   NoPlayerException - Thrown if no Player can be found.

   java.io.IOException - Thrown if there was a problem connecting with the source.

createPlayer

public static Player createPlayer(javax.media.protocol.DataSource source)
                           throws java.io.IOException,
                                  NoPlayerException

Create a Player for the DataSource.

The algorithm for creating a Player from a DataSource is:

1. Get the media content-type-name from the source by calling getContentType.
2. Use the content package-prefix-list to get a list of Player classes that support the media content-type name.
3. For each Player class in the list:
   1. Instantiate a new Player.
   2. Attach the source to the Player by calling setSource on the Player.
   3. If there are no failures, return the new Player; otherwise, try the next Player in the list.
4. If no Player is found for this source:
   1. Use the content package-prefix-list to create a list of Player classes that support the "unknown" content-type-name.
   2. For each Player class in the list:
      1. Instantiate a new Player.
      2. Attach the source to the Player by calling setSource on the Player.
      3. If there are no failures, return the new Player; otherwise, try the next Player in the list.
5. If no Player can be created, a NoPlayerException is thrown.

参数：

DataSource - The DataSource that describes the media content.

返回：

A new Player.

抛出：

NoPlayerException - Thrown if a Player can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

createRealizedPlayer

public static Player createRealizedPlayer(java.net.URL sourceURL)
                                   throws java.io.IOException,
                                          NoPlayerException,
                                          CannotRealizeException

Create a Realized Player for the specified media.

This is a blocking method that creates a Player, calls realize on it and returns only after the Player has been Realized. Realizing a Player could be a time consuming operation and one should use caution when using this method as it could block the thread for several seconds.

参数：

ml - The MediaLocator that describes the source of the media.

返回：

A new Player that is in the Realized state.

抛出：

NoPlayerException - Thrown if a Player can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

CannotRealizeException - Thrown if there was a problem realizing the Player.

createRealizedPlayer

public static Player createRealizedPlayer(MediaLocator ml)
                                   throws java.io.IOException,
                                          NoPlayerException,
                                          CannotRealizeException

Create a Realized Player for the specified media.

This is a blocking method that creates a Player, calls realize on it and returns only after the Player has been Realized. Realizing a Player could be a time consuming operation and one should use caution when using this method as it could block the thread for several seconds.

参数：

ml - The MediaLocator that describes the source of the media.

返回：

A new Player that is in the Realized state.

抛出：

NoPlayerException - Thrown if a Player can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

CannotRealizeException - Thrown if there was a problem realizing the Player.

createRealizedPlayer

public static Player createRealizedPlayer(javax.media.protocol.DataSource source)
                                   throws java.io.IOException,
                                          NoPlayerException,
                                          CannotRealizeException

Create a Realized Player for the specified source.

This is a blocking method that creates a Player, calls realize on it and returns only after the Player has been Realized. Realizing a Player could be a time consuming operation and one should use caution when using this method as it could block the thread for several seconds.

参数：

source - The DataSource that describes the media content.

返回：

A new Player that is in the Realized state.

抛出：

NoPlayerException - Thrown if a Player can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

CannotRealizeException - Thrown if there was a problem realizing the Player.

createProcessor

public static Processor createProcessor(java.net.URL sourceURL)
                                 throws java.io.IOException,
                                        NoProcessorException

Create a Processor for the specified media.

The algorithm is similar to that for creating a Player from a URL

参数：

sourceURL - A URL that describes the media content.

返回：

A Processor for the media described by the source.

抛出：

NoProcessorException - Thrown if no Processor can be found.

java.io.IOException - Thrown if there was a problem connecting with the source.

createProcessor

public static Processor createProcessor(MediaLocator sourceLocator)
                                 throws java.io.IOException,
                                        NoProcessorException

Create a Processor for the specified media.

The algorithm is similar to that for creating a Player from a MediaLocator

参数：

sourceLocator - A MediaLocator that describes the media content.

返回：

A Processor for the media described by the source.

抛出：

NoProcessorException - Thrown if no Processor can be found.

java.io.IOException - Thrown if there was a problem connecting with the source.

createProcessor

public static Processor createProcessor(javax.media.protocol.DataSource source)
                                 throws java.io.IOException,
                                        NoProcessorException

Create a Processor for the DataSource.

The algorithm for creating a Processor is similar to creating a Player from a DataSource.

参数：

DataSource - The DataSource that describes the media content.

返回：

A new Processor.

抛出：

NoProcessorException - Thrown if a Processor can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

createRealizedProcessor

public static Processor createRealizedProcessor(ProcessorModel model)
                                         throws java.io.IOException,
                                                NoProcessorException,
                                                CannotRealizeException

Create a Realized Processor for the specified ProcessorModel.

This method accepts a ProcessorModel that describes the required input and/or output format of the media data. It is a blocking method and returns only after the Processor reaches the Realized state.

参数：

model - The ProcessorModel that describes the input and output media

返回：

A new Processor that is in the Realized state.

抛出：

NoProcessorException - Thrown if a Processor can't be created.

java.io.IOException - Thrown if there was a problem connecting with the source.

CannotRealizeException - Thrown if there was a problem realizing the Player.

另请参见：

ProcessorModel

createDataSource

public static javax.media.protocol.DataSource createDataSource(java.net.URL sourceURL)
                                                        throws java.io.IOException,
                                                               NoDataSourceException

Create a DataSource for the specified media.

参数：

sourceURL - The URL that describes the media data.

返回：

A new DataSource for the media.

抛出：

NoDataSourceException - Thrown if no DataSource can be found.

java.io.IOException - Thrown if there was a problem connecting with the source.

createDataSource

public static javax.media.protocol.DataSource createDataSource(MediaLocator sourceLocator)
                                                        throws java.io.IOException,
                                                               NoDataSourceException

Create a DataSource for the specified media.

Returns a data source for the protocol specified by the MediaLocator. The returned data source is connected; DataSource.connect has been invoked.

The algorithm for creating a DataSource from a MediaLocator is:

1. Get the protocol from the MediaLocator.
2. Use the protocol package-prefix list to get a list of DataSource classes that support the protocol.
3. For each source class in the list:
   1. Instantiate a new DataSource.
   2. Call connect to connect the source.
   3. If there are no errors, return the connected source; otherwise, try the next source in the list.
4. If no source has been found, obtain a URL from the MediaLocator and use it to create a URLDataSource
5. If no source can be found, a NoDataSourceException is thrown.

参数：

sourceLocator - The source protocol for the media data.

返回：

A connected DataSource.

抛出：

NoDataSourceException - Thrown if no DataSource can be found.

java.io.IOException - Thrown if there was a problem connecting with the source.

createMergingDataSource

public static javax.media.protocol.DataSource createMergingDataSource(javax.media.protocol.DataSource[] sources)
                                                               throws IncompatibleSourceException

Creates a merged DataSource from an array of sources. All sources must be of the same type (i.e PullDataSource, PushDataSource, etc.) otherwise an IncompatibleSourceException is thrown. The returned DataSource is of the same type of the given sources. Its content-type is RAW if all sources are of type RAW. Otherwise, its content-type is MIXED.

参数：

sources - the DataSources to be merged

返回：

a DataSource which contains all the streams of the original sources

抛出：

IncompatibleSourceException - if the sources are not of the same type

createCloneableDataSource

public static javax.media.protocol.DataSource createCloneableDataSource(javax.media.protocol.DataSource source)

getSystemTimeBase

public static TimeBase getSystemTimeBase()

Get the time-base object for the system.

返回：

The system time base.

createDataSink

public static DataSink createDataSink(javax.media.protocol.DataSource datasource,
                                      MediaLocator destLocator)
                               throws NoDataSinkException

Create a DataSink for the specified input Datasource and destination Medialocator.

The algorithm for creating a DataSink from a MediaLocator and datasource is:

1. Get the protocol from the MediaLocator.
2. Get a list of MediaHandler classes within the datasink package that support the protocol, using the content package-prefix-list. i.e. search for content-prefix.media.datasink.protocol.Handler
3. For each MediaHandler class in the list:
   1. Instantiate a new MediaHandler.
   2. If the MediaHandler is a DataSink, Attach the source to the MediaHandler by calling MediaHandler.setSource
   3. If there are no failures, return this DataSink;otherwise try the next MediaHandler in the list.
   4. If the MediaHandler is a DataSinkProxy, obtain the content type of the proxy using the getContentType() method. Now obtain a list of MediaHandlers that support the protocol of the Medialocator and the content type returned by the proxy
      i.e. look for content-prefix.media.datasink.protocol.content-type.Handler
   5. If a MediaHandler is found and it is a DataSink, attach the datasource to it by calling MediaHandler.setSource.
      
   6. Return the DataSink if there are no errors.
   7. If no MediaHandler is found, or if there are any errors,try the next MediaHandler
   8. If no DataSink is found after trying all of the handlers, a NoDataSinkException is thrown.

参数：

datasource - The input DataSource to the DataSink

destLocator - A MediaLocator that describes the destination of the media to be handled by the datasink

返回：

A DataSink for the media described by the destLocator and that supports the datasource .

抛出：

NoDataSinkException - Thrown if no DataSink can be found.

另请参见：

NoDataSinkException

getCacheDirectory

public static java.lang.String getCacheDirectory()

Retrieve the directory that's used for playback caching.

返回：

the directory that's used for playback caching, null if the directory is not specified.

setHint

public static void setHint(int hint,
                           java.lang.Object value)

Specify a hint for the Manager to use.

参数：

hint - The name of the hint to be set.

value - The value the hint is to be set.

另请参见：

MAX_SECURITY, CACHING, LIGHTWEIGHT_RENDERER, PLUGIN_PLAYER

getHint

public static java.lang.Object getHint(int hint)

Retrieve the value of a hint set.

参数：

hint - The name of the hint.

返回：

The value of the hint.

另请参见：

MAX_SECURITY, CACHING, LIGHTWEIGHT_RENDERER, PLUGIN_PLAYER

getDataSourceList

public static java.util.Vector getDataSourceList(java.lang.String protocolName)

Build a list of DataSource class names from the protocol prefix-list and a protocol name.

The first name in the list will always be:

 media.protocol.<protocol>.DataSource
 

Each additional name looks like:

 <protocol-prefix>.media.protocol.<protocol>.DataSource
 

for every <protocol-prefix> in the protocol-prefix-list.

参数：

protocol - The name of the protocol the source must support.

返回：

A vector of strings, where each string is a Player class-name.

getHandlerClassList

public static java.util.Vector getHandlerClassList(java.lang.String contentName)

Build a list of Player Handler classes from the content-prefix-list and a content name.

The first name in the list will always be:

 media.content.<contentType>.Handler
 

Each additional name looks like:

 <content-prefix>.media.content.<contentName>.Player
 

for every <content-prefix> in the content-prefix-list.

参数：

contentName - The content type to use in the class name.

返回：

A vector of strings where each one is a Player class-name.

getProcessorClassList

public static java.util.Vector getProcessorClassList(java.lang.String contentName)

Build a list of Processor Handler classes from the content-prefix-list and a content name.

The first name in the list will always be:

 media.processor.<contentType>.Handler
 

Each additional name looks like:

 <content-prefix>.media.processor.<contentName>.Processor
 

for every <content-prefix> in the content-prefix-list.

参数：

contentName - The content type to use in the class name.

返回：

A vector of strings where each one is a Processor class-name.