code.htm

本程序是用java编写的一些关于arq协议实现的小程序

== "kl")</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; if (sender[selected].packet_ack)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; statusMsg
= "Packet "+ selected +" destroyed. Timer running for packet "+base+".";</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; statusMsg
= "Acknowledgement of packet "+ selected +" destroyed. Timer running for
packet "+base+".";</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; sender[selected].on_way
= false;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; kill.setEnabled(false);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; selected
= -1;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; repaint();</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; else if (cmd
== "rst")</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; reset_app();</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; }</font></font><font face="Courier New,Courier"><font size=-1></font></font>
<p><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;public boolean
mouseDown(Event e, int x, int y)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; int i, xpos,
ypos;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; i = (x-h_offset)/(pack_width+7);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; if (sender[i]!=
null)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; xpos =
h_offset+(pack_width+7)*i;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; ypos =
sender[i].packet_pos;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; if (x>=xpos
&amp;&amp; x&lt;= xpos+pack_width &amp;&amp; sender[i].on_way)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; if
((sender[i].packet_ack &amp;&amp; y>=v_offset+ypos &amp;&amp; y&lt;=v_offset+ypos+pack_height)
|| ((!sender[i].packet_ack) &amp;&amp; y>=v_offset+v_clearance-ypos &amp;&amp;
y&lt;=v_offset+v_clearance-ypos+pack_height))</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
{</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
statusMsg = "Packet "+ i +" selected.";</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
sender[i].selected = true;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
selected = i;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
kill.setEnabled(true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
}</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
statusMsg = "Click on a moving packet to select.";</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; statusMsg
= "Click on a moving packet to select.";</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; return true;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1></font></font>&nbsp;<font face="Courier New,Courier"><font size=-1></font></font>
<p><font face="Courier New,Courier"><font size=-1>&nbsp;public void paint(Graphics
g)&nbsp;&nbsp;&nbsp; // To eliminate flushing, update is overriden</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; update(g);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;public void update(Graphics
g)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; Dimension d =
size();</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; //Create the
offscreen graphics context, if no good one exists.</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
if ((offGraphics == null) || (d.width != offDimension.width) || (d.height
!= offDimension.height))</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offDimension = d;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offImage = createImage(d.width, d.height);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics = offImage.getGraphics();</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; //Erase the previous
image.</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor(Color.white);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.fillRect(0, 0, d.width, d.height);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; //drawing window</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; offGraphics.setColor(Color.black);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; offGraphics.draw3DRect(h_offset+base*(pack_width+7)-4,
v_offset-3, (window_len)*(pack_width+7)+1, pack_height+6,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp; for (int i=0;
i&lt;total_packet; i++)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; // drawing
the sending row</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; if (sender[i]==null)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; offGraphics.setColor(Color.black);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; offGraphics.draw3DRect(h_offset+(pack_width+7)*i,
v_offset, pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; offGraphics.draw3DRect(h_offset+(pack_width+7)*i,
v_offset+v_clearance, pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; }</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; {</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; if
(sender[i].acknowledged)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor(ack_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor(unack_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; offGraphics.fill3DRect
(h_offset+(pack_width+7)*i, v_offset,pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; //
drawing the destination packets</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; offGraphics.setColor
(dest_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; if
(sender[i].reached_dest)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.fill3DRect (h_offset+(pack_width+7)*i, v_offset+v_clearance,pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.draw3DRect (h_offset+(pack_width+7)*i, v_offset+v_clearance,pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; //
drawing the moving packets</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp; if
(sender[i].on_way)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
{</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
if (i==selected)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor (sel_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
else if (sender[i].packet_ack)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor (roam_pack_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
else</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.setColor (roam_ack_color);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;
if (sender[i].packet_ack)</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
offGraphics.fill3DRect (h_offset+(pack_width+7)*i, v_offset+sender[i].packet_pos,pack_width,pack_height,true);</font></font>
<br><font face="Courier New,Courier"><font size=-1>&nbsp;&nbsp;&nbsp;&nbsp;