<div>> Squeak image is not designed as a multi-user, transactional image so using the </div>
<div>> image in that way can be a headache when your application grows.<br> </div>
<div>I was thinking thath squeak is developed especially about this.<br><br> </div>
<div><span class="gmail_quote">2006/3/17, Diego Fernandez <<a href="mailto:diegof79@gmail.com">diegof79@gmail.com</a>>:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><br>
<div><span class="q"><span class="gmail_quote">On 3/16/06, <b class="gmail_sendername">William G. Davis</b> <<a onclick="return top.js.OpenExtLink(window,event,this)" href="mailto:william_gordon_davis@yahoo.com" target="_blank">
william_gordon_davis@yahoo.com</a>> wrote:<br></span><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Right now I have a class that stores objects for later<br>retrieval in several collections. The persistence is
<br>achieved by making the class a Singleton; it stores an<br>instance of itself in a class variable and provides<br>access to the object with a class message (#instance).</blockquote></span>
<div><br>Why not using a global to save the instance, instead of a "Singleton" with class variables?<br>This is unnecessary in St.<br>Singleton means "single-instance", but some people make a wrong use of this pattern to make well known instances --globals. Note that except for "null objects", is very difficult to known if class represents something unique, so singletons are usually used only for performance reasons.
<br> </div><span class="q"><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Is this a bad system? Should I be using something<br>else? </blockquote></span>
<div><br>Except for the singletons it's not bad :), you can design your system in that way and then add other persistence mechanisms when necessary. </div><span class="q"><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">Will this cause too much of a headache when<br>upgrading Squeak or transferring data from one machine
<br>to another?<br><br></blockquote></span></div><br>Yes :(<br>Squeak image is not designed as a multi-user, transactional image so using the image in that way can be a headache when your application grows.<br><br>Maybe you can use some OODB to solve this problem, (the most used OODB is GemStone, that is a St prepared for persistence: an image with multi-user and transaction support, is very powerful but is very expensive for a small project :(, take a look at:
<a onclick="return top.js.OpenExtLink(window,event,this)" href="http://www.gemstone.com/" target="_blank">http://www.gemstone.com/</a> and <a onclick="return top.js.OpenExtLink(window,event,this)" href="http://minnow.cc.gatech.edu/squeak/1957" target="_blank">
http://minnow.cc.gatech.edu/squeak/1957</a> )<br><br>There are some free OODB frameworks for Squeak:<br>MinneStore: <a onclick="return top.js.OpenExtLink(window,event,this)" href="http://minnestore.sourceforge.net/index.html" target="_blank">
http://minnestore.sourceforge.net/index.html</a><br>Magma: <a onclick="return top.js.OpenExtLink(window,event,this)" href="http://minnow.cc.gatech.edu/squeak/2665" target="_blank">http://minnow.cc.gatech.edu/squeak/2665</a>
<br><br><br><br><br><br><br><br></blockquote></div><br>