player.html

JMF原版英文说明文档

 <p>

 When a <code>Controller</code> is added to a
 <code>Player</code>, the <code>Player</code>
 does not transition the added <code>Controller</code> to
 new state, nor does the <code>Player</code> transition itself
 forward.
 The <code>Player</code> either transitions back to the
 <i>realized</i> state if the added <code>Controller</code>
 is <i>realized</i> or <i>prefetching</i> or it stays
 in the <i>prefetched</i> state if the both the <code>Player</code>
 and the added <code>Controller</code> are in the <i>prefetched</i>
 state. If the <code>Player</code> makes a state transition
 as a result of adding a <code>Controller</code> the <code>Player</code>
 posts a <code>TransitionEvent</code>.
 
 <h3>Removing a Controller</h3>

 To stop a <code>Player</code> from managing another
 <code>Controller</code>, call <code>removeController</code>.
 The managing <code>Player</code> must be <i>Stopped</i> before
 <code>removeController</code> can be called.
 A <code>ClockStartedError</code> is thrown if <code>removeController</code>
 is called on a <i>Started</i>&nbsp;<code>Player</code>.
 <p>

 When a <code>Controller</code> is removed from a <code>Player's</code>
 control, the <code>Player</code>:
 <ul>
 <li> Resets the <code>Controller's</code>&nbsp;<code>TimeBase</code>
 to its default.
 <li> Recalculates its duration and posts a
 <code>DurationUpdateEvent</code> if the <code>Player's</code> duration
 is different without the <CODE>Controller</CODE> added.
 <li> Recalculates its start latency.
 </ul>

 <h3>Setting the Media Time and Rate of a Managing Player</h3>

 When you call <code>setMediaTime</code> on a <code>Player</code> that's
 managing other <code>Controllers</code>,
 its actions differ depending on whether or not the <code>Player</code>
 is <I>Started</I>.
 If the <code>Player</code> is not <i>Started</i>, it simply
 invokes <code>setMediaTime</code> on all of the
 <code>Controllers</code> it's managing.
 <p>

 If the <code>Player</code> is <i>Started</i>,
 it posts a <code>RestartingEvent</code> and
 performs the following tasks for each managed <code>Controller</code>:
 
 <ul>
 <li>Invokes <code>stop</code> on the <code>Controller</code>.
 <li>Invokes <code>setMediaTime</code> on the <code>Controller</code>.
 <li>Invokes <code>prefetch</code> on the <code>Controller</code>.
 <li>Waits for a <code>PrefetchCompleteEvent</code> from
 the <code>Controller</code>.
 <li>Invokes <code>syncStart</code> on the <code>Controller</code>
 </ul>

 <p>

 The same is true when <code>setRate</code> is called on a
 managing <code>Player</code>.
 The <code>Player</code> attempts to set the specified rate
 on all managed <code>Controllers</code>, stopping and restarting
 the <code>Controllers</code> if necessary.
 If some of the <code>Controllers</code> do not support the requested rate,
 the <code>Player</code> returns the rate that was actually set.
 All <code>Controllers</code> are guaranteed to have been successfully
 set to the rate returned. 
 
 <h3>Starting a Managing Player</h3>
 When you call <code>start</code> on a managing <code>Player</code>,
 all of the  <code>Controllers</code> managed by
 the <code>Player</code> are transitioned to
 the <i>Prefetched</i> state. When the <code>Controllers</code>
 are <i>Prefetched</i>,
 the managing <code>Player</code> calls <code>syncStart</code>
 with a time consistent with the latencies of each of the managed
 <code>Controllers</code>.
  
 
 <h3>Calling realize, prefetch, stop, or deallocate on a Managing Player</h3>
 
 When you call <code>realize</code>, <code>prefetch</code>, 
 <code>stop</code>,  or <code>deallocate</code> on a managing
 <code>Player</code>, 
 the <code>Player</code> calls that method on all of the 
 <code>Controllers</code> that it is managing.
 The <code>Player</code> moves from one state to the
 next when all of its <code>Controllers</code> have reached that state. 
 For example, a <code>Player</code> in the <i>Prefetching</i>
 state does not transition into the <i>Prefetched</i>
 state until all of its managed <code>Controllers</code>
 are <i>Prefetched</i>.
 The  <code>Player</code> posts <code>TransitionEvents</code> normally
 as it changes state.
 <p>

 <h3>Calling syncStart or setStopTime on a Managing Player</h3>
 When you call <code>syncStart</code> or <code>setStopTime</code> on a
 managing <code>Player</code>, the <code>Player</code>
 calls that method  on all of the <code>Controllers</code> that it
 is managing. (The <code>Player</code> 
 must be in the correct state or an error is thrown.
 For example, the <code>Player</code> must be <I>Prefetched</I>
 before you can call <code>syncStart</code>.)
 
 <h3>Setting the Time Base of a Managing Player</h3>
 When <code>setTimeBase</code> is called on a managing <code>Player</code>,
 the <code>Player</code> calls <code>setTimeBase</code> on all of
 the <code>Controllers</code> it's managing. 
 If <code>setTimeBase</code> fails on any of the <code>Controllers</code>,
 an <code>IncompatibleTimeBaseException</code> is thrown
 and the  <code>TimeBase</code> last used
 is restored for all of the <code>Controllers</code>.
 
 <h3>Getting the Duration of a Managing Player</h3>
 Calling <code>getDuration</code> on a managing <code>Player</code>
 returns the maximum duration of all of the added
 <code>Controllers</code> and the managing <code>Player</code>.
 If the <CODE>Player</CODE>  or any <CODE>Controller</CODE>
 has not resolved its duration, <code>getDuration</code>
 returns <code>Duration.DURATION_UNKNOWN</code>.

 <h3> Closing a Managing Player</h3>
 When <code>close</code> is called on a managing <code>Player</code>
 all managed <code>Controllers</code> are closed as well.
 
 <a name="events"><h3>Events</h3></a>
 Most events posted by a managed <code>Controller</code> are filtered
 by the managing <code>Player</code>. Certain events are sent directly
 from the <code>Controller</code> through the <code>Player</code> and to the
 listeners registered with the <code>Player</code>.
 <p>

 To handle the events that a managed <code>Controller</code> can generate,
 the <code>Player</code> registers a listener with the
 <code>Controller</code> when it is added.
 Other listeners that are registered with the <code>Controller</code>
 must be careful not to invoke methods on the <code>Controller</code>
 while it is being managed by the <code>Player</code>.
 Calling a control method on a managed <code>Controller</code> directly
 will produce unpredictable results.
 <p>

 When a <CODE>Controller</CODE> is removed from the <code>Player's</code>
 list of managed <code>Controllers</code>,
 the <code>Player</code> removes itself from the <code>Controller's</code>
 listener list.
 
 <h4>Transition Events</h4>
 A managing <code>Player</code> posts <code>TransitionEvents</code> normally 
 as it moves between states, but
 the managed <code>Controllers</code> affect when the <code>Player</code>
 changes state.
 In general, 
 a <code>Player</code> does not post a transition event until all of its
 managed <code>Controllers</code> have posted the event.
 
 <h4>Status Change Events</h4>
 The managing <code>Player</code> collects the
 <code>RateChangeEvents</code>, <code>StopTimeChangeEvents</code>,
 and <code>MediaTimeSetEvents</code> posted by its
 managed <code>Controllers</code> and posts a single event for the group.
 
 <h4>DurationUpdateEvent</h4>
 A <code>Player</code> posts a <code>DurationUpdateEvent</code> when
 it determines its duration or its duration changes.
 A managing <code>Player's</code> duration might change if a managed
 <code>Controller</code> updates or discovers its duration.
 In general, if a managed <code>Controller</code> 
 posts a <code>DurationUpdateEvent</code> and the new duration
 changes the managing <code>Player's</code> duration,
 the <code>Player</code> posts a <code>DurationUpdateEvent</code>

 <h4>CachingControlEvent</h4>
 A managing <CODE>Player</CODE> reposts <CODE>CachingControlEvents</CODE>
 received from a <CODE>Players</CODE> that it manages, but otherwise
 ignores the events.

 <h4>ControllerErrorEvents</h4>
 A managing <CODE>Player</CODE> immediately reposts
 any <CODE>ControllerErrorEvent</CODE> received from a
 <CODE>Controller</CODE> that it is managing.
 After a <CODE>ControllerErrorEvent</CODE> has been
 received from a managed <CODE>Controller</CODE>, a
 managing <CODE>Player</CODE> no longer invokes any methods
 on the managed <CODE>Controller</CODE>; the
 managed <CODE>Controller</CODE> is ignored from that point on.
<P>
<DL>
<DT><B>See Also: </B><DD><A HREF="../../javax/media/Manager.html"><CODE>Manager</CODE></A>, 
<A HREF="../../javax/media/GainControl.html"><CODE>GainControl</CODE></A>, 
<A HREF="../../javax/media/Clock.html"><CODE>Clock</CODE></A>, 
<A HREF="../../javax/media/TransitionEvent.html"><CODE>TransitionEvent</CODE></A>, 
<A HREF="../../javax/media/RestartingEvent.html"><CODE>RestartingEvent</CODE></A>, 
<A HREF="../../javax/media/DurationUpdateEvent.html"><CODE>DurationUpdateEvent</CODE></A>, 
<CODE>Component</CODE></DL>
<HR>

<P>
<!-- ======== INNER CLASS SUMMARY ======== -->


<!-- =========== FIELD SUMMARY =========== -->

<A NAME="fields_inherited_from_class_javax.media.Controller"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TD><B>Fields inherited from interface javax.media.<A HREF="../../javax/media/Controller.html">Controller</A></B></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../javax/media/Controller.html#LATENCY_UNKNOWN">LATENCY_UNKNOWN</A>,  
<A HREF="../../javax/media/Controller.html#Prefetched">Prefetched</A>,  
<A HREF="../../javax/media/Controller.html#Prefetching">Prefetching</A>,  
<A HREF="../../javax/media/Controller.html#Realized">Realized</A>,  
<A HREF="../../javax/media/Controller.html#Realizing">Realizing</A>,  
<A HREF="../../javax/media/Controller.html#Started">Started</A>,  
<A HREF="../../javax/media/Controller.html#Unrealized">Unrealized</A></CODE></TD>
</TR>
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&nbsp;<A NAME="fields_inherited_from_class_javax.media.Clock"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
<TR BGCOLOR="#EEEEFF" CLASS="TableSubHeadingColor">
<TD><B>Fields inherited from interface javax.media.<A HREF="../../javax/media/Clock.html">Clock</A></B></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../javax/media/Clock.html#RESET">RESET</A></CODE></TD>
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&nbsp;<A NAME="fields_inherited_from_class_javax.media.Duration"><!-- --></A>
<TABLE BORDER="1" CELLPADDING="3" CELLSPACING="0" WIDTH="100%">
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<TD><B>Fields inherited from interface javax.media.<A HREF="../../javax/media/Duration.html">Duration</A></B></TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD><CODE><A HREF="../../javax/media/Duration.html#DURATION_UNBOUNDED">DURATION_UNBOUNDED</A>,  
<A HREF="../../javax/media/Duration.html#DURATION_UNKNOWN">DURATION_UNKNOWN</A></CODE></TD>
</TR>
</TABLE>
&nbsp;
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<B>Method Summary</B></FONT></TD>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Player.html#addController(javax.media.Controller)">addController</A></B>(<A HREF="../../javax/media/Controller.html">Controller</A>&nbsp;newController)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Tells the <CODE>Player</CODE> to assume control of another <code>Controller</code>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;java.awt.Component</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Player.html#getControlPanelComponent()">getControlPanelComponent</A></B>()</CODE>

<BR>