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SUMMARY: INNER | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Object | +--javax.microedition.media.Manager
Manager
is the access point for obtaining
system dependent resources such as Players
for multimedia processing.
A Player is an object used to control and render media that is specific to the content type of the data.
Manager
provides access to an implementation specific
mechanism for constructing Players
.
For convenience, Manager
also provides a simplified
method to generate simple tones.
The
playTone
function is defined to generate
tones. Given the note and duration, the function will
produce the specified tone.
Manager
provides two methods to create aPlayer
for playing back media:The
- Create from a media locator.
- Create from an
InputStream
.Player
returned can be used to control the presentation of the media.
Content types identify the type of media data. They are defined to be the registered MIME types ( http://www.iana.org/assignments/media-types/); plus some user-defined types that generally follow the MIME syntax (RFC 2045, RFC 2046).For example, here are a few common content types:
- Wave audio files:
audio/x-wav
- AU audio files:
audio/basic
- MP3 audio files:
audio/mpeg
- MIDI files:
audio/midi
- Tone sequences:
audio/x-tone-seq
Media locators are specified in URI syntax which is defined in the form:<scheme>:<scheme-specific-part>
The "scheme" part of the locator string identifies the name of the protocol being used to deliver the data.
Player
Field Summary | |
static String |
TONE_DEVICE_LOCATOR
The locator to create a tone Player
to play back tone sequences. |
Method Summary | |
static Player |
createPlayer(InputStream stream,
String type)
Create a Player to play back media from an
InputStream . |
static Player |
createPlayer(String locator)
Create a Player from an input locator. |
static String[] |
getSupportedContentTypes(String protocol)
Return the list of supported content types for the given protocol. |
static String[] |
getSupportedProtocols(String content_type)
Return the list of supported protocols given the content type. |
static void |
playTone(int note,
int duration,
int volume)
Play back a tone as specified by a note and its duration. |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
public static final String TONE_DEVICE_LOCATOR
Player
to play back tone sequences. e.g.
try { Player p = Manager.createPlayer(Manager.TONE_DEVICE_LOCATOR); p.realize(); ToneControl tc = (ToneControl)p.getControl("ToneControl"); tc.setSequence(mySequence); p.start(); } catch (IOException ioe) { } catch (MediaException me) {}If a tone sequence is not set on the tone
Player
via its ToneControl
,
the Player
does not carry any
sequence. getDuration
returns 0 for this
Player
.
The content type of the Player
created from this
locator is audio/x-tone-seq
.
A Player
for this locator may not be supported
for all implementations.
Value "device://tone" is assigned to TONE_DEVICE_LOCATOR
.
Method Detail |
public static String[] getSupportedContentTypes(String protocol)
See content types for the syntax of the content types returned. See protocol name for the syntax of the protocol used.
For example, if the given protocol
is "http"
,
then the supported content types that can be played back
with the http
protocol will be returned.
If null
is passed in as the protocol
,
all the supported content types for this implementation
will be returned. The returned array must be non-empty.
If the given protocol
is an invalid or
unsupported protocol, then an empty array will be returned.
protocol
- The input protocol for the supported content types.public static String[] getSupportedProtocols(String content_type)
Player
's.
See protocol name for the syntax of the protocols returned. See content types for the syntax of the content type used.
For example, if the given content_type
is "audio/x-wav"
, then the supported protocols
that can be used to play back audio/x-wav
will be returned.
If null
is passed in as the
content_type
,
all the supported protocols for this implementation
will be returned. The returned array must be non-empty.
If the given content_type
is an invalid or
unsupported content type, then an empty array will be returned.
content_type
- The content type for the supported protocols.public static Player createPlayer(String locator) throws IOException, MediaException
Player
from an input locator.locator
- A locator string in URI syntax that describes
the media content.Player
.IllegalArgumentException
- Thrown if locator
is null
.MediaException
- Thrown if a Player
cannot
be created for the given locator.IOException
- Thrown if there was a problem connecting
with the source pointed to by the locator
.SecurityException
- Thrown if the caller does not
have security permission to create the Player
.public static Player createPlayer(InputStream stream, String type) throws IOException, MediaException
Player
to play back media from an
InputStream
.
The type
argument
specifies the content-type of the input media. If
null
is given, Manager
will
attempt to determine the type. However, since determining
the media type is non-trivial for some media types, it
may not be feasible in some cases. The
Manager
may throw a MediaException
to indicate that.
stream
- The InputStream
that delivers the
input media.type
- The ContentType
of the media.Player
.IllegalArgumentException
- Thrown if stream
is null
.MediaException
- Thrown if a Player
cannot
be created for the given stream and type.IOException
- Thrown if there was a problem reading data
from the InputStream
.SecurityException
- Thrown if the caller does not
have security permission to create the Player
.public static void playTone(int note, int duration, int volume) throws MediaException
SEMITONE_CONST = 17.31234049066755 = 1/(ln(2^(1/12))) note = ln(freq/8.176)*SEMITONE_CONST The musical note A = MIDI note 69 (0x45) = 440 Hz.This call is a non-blocking call. Notice that this method may utilize CPU resources significantly on devices that don't have hardware support for tone generation.
note
- Defines the tone of the note as specified by the
above formula.duration
- The duration of the tone in milli-seconds.
Duration must be positive.volume
- Audio volume range from 0 to 100. 100 represents
the maximum
volume at the current hardware level. Setting the volume to a
value less
than 0 will set the volume to 0. Setting the volume to greater than
100 will set the volume to 100.IllegalArgumentException
- Thrown if the given note or
duration is out of range.MediaException
- Thrown if the tone cannot be played
due to a device-related problem.
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