clock.html

JMF原版英文说明文档

 A <code>Clock</code> returns to the <i>Stopped</i> state immediately
 when the <code>stop</code> method is called or the
 <i>media time</i> passes the stop time.
 <p>

 Certain methods can only be invoked when the <code>Clock</code> is in a
 particular state.
 If the <code>Clock</code> is in the wrong state when one of these methods
 is called, an error or exception is thrown.
 
 <h3>Methods Restricted to <i>Started</i> Clocks</h3>

 The <code>mapToTimeBase</code> method can only be called on a 
 <code>Clock</code> in the <i>Started</i> state. 
 If it is invoked on a <i>Stopped</i>&nbsp;<code>Clock</code>,
 a <code>ClockStoppedException</code> is thrown.
 This is because the <code>Clock</code> is not synchronized to
 a <code>TimeBase</code> when it is <i>Stopped</i>.

 <h3>Methods Restricted to <i>Stopped</i> Clocks</h3>

 The following methods can only be called on a  
 <code>Clock</code> in the <i>Stopped</i> state.
 If invoked on a <i>Started</i>&nbsp;
 <code>Clock</code>, these methods throw a <code>ClockStartedError</code>.
 <ul>
 <li> <code>syncStart</code>
 <li> <code>setTimeBase</code>
 <li> <code>setMediaTime</code>
 <li> <code>setRate</code>
 </ul>
 
 Resetting the rate, the <i>media time</i>, the time base, or the 
 <i>time-base start-time</i> implies a complete remapping 
 between the <code>Clock</code> and its
 <code>TimeBase</code> and is not allowed on
 a <i>Started</i>&nbsp;<code>Clock</code>. 

 <h3>Methods with Additional Restrictions</h3>
 
 A race condition occurs if a new <i>media stop-time</i> is set
 when a <code>Clock</code> is already approaching a previously
 set <i>media stop-time</i>.
 In this situation, it impossible to guarantee when the <code>Clock</code>
 will stop. To prevent this race condition, <code>setStopTime</code> can
 only be set once on  a <i>Started</i>&nbsp;<code>Clock</code>.
 A <code>StopTimeSetError</code> is thrown if <code>setStopTime</code>
 is called and the <i>media stop-time</i> has already been set.
 <p>

 There are no restrictions on calling <code>setStopTime</code> on a 
 <i>Stopped</i>&nbsp;<code>Clock</code>; the stop time can always be
 reset if  the <code>Clock</code> is <i>Stopped</i>.
<P>
<DL>
<DT><B>See Also: </B><DD><A HREF="../../javax/media/TimeBase.html"><CODE>TimeBase</CODE></A>, 
<A HREF="../../javax/media/Player.html"><CODE>Player</CODE></A></DL>
<HR>

<P>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>static&nbsp;<A HREF="../../javax/media/Time.html">Time</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#RESET">RESET</A></B></CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Returned by <CODE>getStopTime</CODE> if the stop-time is unset.</TD>
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<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;long</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getMediaNanoseconds()">getMediaNanoseconds</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets this <code>Clock's</code> current <i>media time</i>
 in nanoseconds.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../javax/media/Time.html">Time</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getMediaTime()">getMediaTime</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets this <code>Clock's</code> current <i>media time</i>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;float</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getRate()">getRate</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets the current temporal scale factor.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../javax/media/Time.html">Time</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getStopTime()">getStopTime</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets the last value successfully set by <CODE>setStopTime</CODE>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../javax/media/Time.html">Time</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getSyncTime()">getSyncTime</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets the current <i>media time</i> or the time until this
 <code>Clock</code> will synchronize to its <code>TimeBase</code>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../javax/media/TimeBase.html">TimeBase</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#getTimeBase()">getTimeBase</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets the <code>TimeBase</code> that this <code>Clock</code> is using.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;<A HREF="../../javax/media/Time.html">Time</A></CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#mapToTimeBase(javax.media.Time)">mapToTimeBase</A></B>(<A HREF="../../javax/media/Time.html">Time</A>&nbsp;t)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Gets the <code>TimeBase</code> time corresponding to the specified <i>media time</i>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#setMediaTime(javax.media.Time)">setMediaTime</A></B>(<A HREF="../../javax/media/Time.html">Time</A>&nbsp;now)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sets the <code>Clock's</code>&nbsp;<i>media time</i>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;float</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#setRate(float)">setRate</A></B>(float&nbsp;factor)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sets the temporal scale factor.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#setStopTime(javax.media.Time)">setStopTime</A></B>(<A HREF="../../javax/media/Time.html">Time</A>&nbsp;stopTime)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sets the <i>media time</i> at which you want the <code>Clock</code>
 to stop.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#setTimeBase(javax.media.TimeBase)">setTimeBase</A></B>(<A HREF="../../javax/media/TimeBase.html">TimeBase</A>&nbsp;master)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Sets the <code>TimeBase</code> for this <code>Clock</code>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#stop()">stop</A></B>()</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Stops the <code>Clock</code>.</TD>
</TR>
<TR BGCOLOR="white" CLASS="TableRowColor">
<TD ALIGN="right" VALIGN="top" WIDTH="1%"><FONT SIZE="-1">
<CODE>&nbsp;void</CODE></FONT></TD>
<TD><CODE><B><A HREF="../../javax/media/Clock.html#syncStart(javax.media.Time)">syncStart</A></B>(<A HREF="../../javax/media/Time.html">Time</A>&nbsp;at)</CODE>

<BR>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Synchronizes the current <i>media time</i> to the specified 
 <I>time-base time</I> and start the <code>Clock</code>.</TD>
</TR>
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<A NAME="RESET"><!-- --></A><H3>
RESET</H3>
<PRE>
public static final <A HREF="../../javax/media/Time.html">Time</A> <B>RESET</B></PRE>
<DL>
<DD>Returned by <CODE>getStopTime</CODE> if the stop-time is unset.</DL>

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<A NAME="setTimeBase(javax.media.TimeBase)"><!-- --></A><H3>
setTimeBase</H3>
<PRE>
public void <B>setTimeBase</B>(<A HREF="../../javax/media/TimeBase.html">TimeBase</A>&nbsp;master)
                 throws <A HREF="../../javax/media/IncompatibleTimeBaseException.html">IncompatibleTimeBaseException</A></PRE>
<DL>
<DD>Sets the <code>TimeBase</code> for this <code>Clock</code>.
 This method can only be called on a 
 <i>Stopped</i>&nbsp;<code>Clock</code>.
 A <code>ClockStartedError</code> is thrown if
 <code>setTimeBase</code> is called on a <i>Started</i>&nbsp;
 <code>Clock</code>.    
 
 <p>
 A <code>Clock</code> has a default <code>TimeBase</code> that
 is determined by the implementation. 
 To reset a <code>Clock</code> to its default 
 <code>TimeBase</code>, call <code>setTimeBase(null)</code>.<DD><DL>
<DT><B>Parameters:</B><DD><CODE>master</CODE> - The new <CODE>TimeBase</CODE> or <CODE>null</CODE> to reset the <code>Clock</code>
 to its default <code>TimeBase</code>.<DT><B>Throws:</B><DD><A HREF="../../javax/media/IncompatibleTimeBaseException.html">IncompatibleTimeBaseException</A> - Thrown if
 the <code>Clock</code> can't use the specified <code>TimeBase</code>.</DL>
</DD>
</DL>