ItemNotFound class - Revision history

JAL at 21:29, 18 November 2014

2014-11-18T21:29:04Z

← Older revision		Revision as of 21:29, 18 November 2014
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	===Usage notes===		===Usage notes===
	<ul>		<ul>
	<li>As described in [[Object variables#Using New or other Constructors\|"Using New or other Constructors"]], <var>New</var> can be invoked with no object, with an explicit class name, or with an object variable in the class, even if that object is <var>Null</var>:		<li>As described in [[Object variables#Using New or other Constructors\|Using New or other Constructors]], <var>New</var> can be invoked with no object, with an explicit class name, or with an object variable in the class, even if that object is <var>Null</var>:
	<p class="code">%itemnfd = new		<p class="code">%itemnfd = new

JAL at 22:32, 23 September 2014

2014-09-23T22:32:18Z

New page

__NOTOC__
An <var>ItemNotFound</var> exception indicates that a collection object search located no collection items that satisfy the selection criterion specified in the collection method that invoked the search.
There are several [[Collections#Searching a collection|searching]] methods, but only those that return a single found item produce an <var>ItemNotFound</var> exception.

This exception class has no properties. It is simply a notification that a valid search found no items that met the selection criterion.

The class's only method is the <var>[[New (ItemNotFound_constructor)|New]]</var> constructor, which you would typically use with a <var class="product">SOUL</var> <var>[[Throw statement|Throw]]</var> statement to produce an <var>ItemNotFound</var> exception yourself.
For example:
<p class="code">throw %(itemNotFound):new
</p>

Remember that you catch an exception with the <var>[[Exceptions#Try and Catch|Catch]]</var> statement; if an exception condition occurs outside a
<var>Catch</var> for it, the request is cancelled.
For example, if you expect one or no matches from your search, you might specify a block like the following:
<p class="code">[[Exceptions#Try and Catch|try]] %terminationInfo = %terminationList:findNextItem (eq(custId, %custid)
... process the termination info
catch itemNotFound
end try
</p>

On the other hand, if you always expect a match, you might want a program crash to result if you are wrong about the match, so you could leave out a <var>Try/Catch</var>.

The <var>Try/Catch</var> approach is slightly more efficient than a test for a zero result. <var>[[Exceptions#Try and Catch|Try]]</var> generates no quads other than the branch around the catch block if the search succeeds. And in fact, you could put a <var>Try</var> around a loop and use the <var>ItemNotFound</var> exception to exit the loop:
<p class="code">%i = 0
try
repeat forever
%i = %colla:findNextItemNumber(<criterion>), start=%i)
%obj = %colla(%i)
... process the object
end repeat
catch itemNotFound
end try
</p>

The <var>ItemNotFound</var> class is available as of <var class="product">Sirius Mods</var> version 7.6.

==The ItemNotFound methods==
{{Template:List of ItemNotFound methods}}

The methods in the class are described in the subsections that follow. In addition:
<ul>
<li>[[Notation conventions for methods]] has information about the conventions followed. </li>
<li>[[ItemNotFound methods syntax]] is a single page that contains the syntax diagrams of all the methods in the class. </li>
</ul>

==New constructor==
{{Template:ItemNotFound:New subtitle}}

This method generates an instance of an <var>[[ItemNotFound class|ItemNotFound]]</var> exception. The <var>New</var> method format follows:

===Syntax===
{{Template:ItemNotFound:New syntax}}

====Syntax terms====
<table>
<tr><th>%itemNotFound</th>
<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.
</td></tr>

<tr><th><var>[%(ItemNotFound):]</var></th>
<td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors|Constructor]]</var>. See [[#Usage notes|Usage notes]], below, for more information about invoking an <var>ItemNotFound</var> <var>Constructor</var>.</td></tr>
</table>

===Usage notes===
<ul>
<li>As described in [[Object variables#Using New or other Constructors|"Using New or other Constructors"]], <var>New</var> can be invoked with no object, with an explicit class name, or with an object variable in the class, even if that object is <var>Null</var>:
<p class="code">%itemnfd = new

%itemnfd = %(ItemNotFound):new

%itemnfd = %itemnfd:new
</p></li>
</ul>

[[Category:System exception classes]]

JAL2 at 18:03, 7 August 2012

2012-08-07T18:03:11Z

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	~~<h2>~~New constructor~~</h2>~~		==New constructor==
	{{Template:ItemNotFound:New subtitle}}		{{Template:ItemNotFound:New subtitle}}

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	<h3>Syntax</h3>		<h3>Syntax</h3>
	{{Template:ItemNotFound:New syntax}}		{{Template:ItemNotFound:New syntax}}

	<h4>Syntax terms</h4>		<h4>Syntax terms</h4>
	<table class="syntaxTable">		<table class="syntaxTable">

	<tr><th>%itemNotFound</th>		<tr><th>%itemNotFound</th>
	<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.		<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.
	</td></tr>		</td></tr>
	<tr><th><var>%(ItemNotFound)</var></th>
			<tr><th><var>[%(ItemNotFound):]</var></th>
	<td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors\|Constructor]]</var>. See [[#Usage notes\|"Usage notes"]], below, for more information about invoking an <var>ItemNotFound</var> <var>Constructor</var>.</td></tr>		<td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors\|Constructor]]</var>. See [[#Usage notes\|"Usage notes"]], below, for more information about invoking an <var>ItemNotFound</var> <var>Constructor</var>.</td></tr>
	</table>		</table>

JAL2 at 17:02, 7 August 2012

2012-08-07T17:02:58Z

← Older revision		Revision as of 17:02, 7 August 2012
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	</p>		</p>

	Remember that you catch an exception with the <var>[[Catch ~~statement~~\|Catch]]</var> statement; if an exception condition occurs outside a		Remember that you catch an exception with the <var>[[Exceptions#Try and Catch\|Catch]]</var> statement; if an exception condition occurs outside a
	<var>Catch</var> for it, the request is cancelled.		<var>Catch</var> for it, the request is cancelled.
	For example, if you expect one or no matches from your search, you might specify a block like the following:		For example, if you expect one or no matches from your search, you might specify a block like the following:
	<p class="code">[[try]] %terminationInfo = %terminationList:findNextItem (eq(custId, %custid)		<p class="code">[[Exceptions#Try and Catch\|try]] %terminationInfo = %terminationList:findNextItem (eq(custId, %custid)
	... process the termination info		... process the termination info
	[[catch]] itemNotFound		catch itemNotFound
	end try		end try
	</p>		</p>

JAL2 at 22:16, 30 March 2012

2012-03-30T22:16:32Z

← Older revision		Revision as of 22:16, 30 March 2012
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	{{Template:ItemNotFound:New subtitle}}		{{Template:ItemNotFound:New subtitle}}

	This ~~[[Notation conventions for methods\|callable]] constructor~~ generates an instance of an <var>[[ItemNotFound_class\|ItemNotFound]]</var> exception. The <var>New</var> method format follows:		This method generates an instance of an <var>[[ItemNotFound_class\|ItemNotFound]]</var> exception. The <var>New</var> method format follows:

	<h3>Syntax</h3>		<h3>Syntax</h3>

Alex at 20:22, 19 October 2011

2011-10-19T20:22:25Z

← Older revision		Revision as of 20:22, 19 October 2011
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	</p>		</p>

	The <var>ItemNotFound</var> class is available as of <var class="product">~~[[Category:System exception classes]]~~</var> version 7.6.		The <var>ItemNotFound</var> class is available as of <var class="product">Sirius Mods</var> version 7.6.

JAL2 at 23:01, 8 August 2011

2011-08-08T23:01:57Z

← Older revision		Revision as of 23:01, 8 August 2011
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	<var>Catch</var> for it, the request is cancelled.		<var>Catch</var> for it, the request is cancelled.
	For example, if you expect one or no matches from your search, you might specify a block like the following:		For example, if you expect one or no matches from your search, you might specify a block like the following:
	<p class="code">[[try]] %terminationInfo = -		<p class="code">[[try]] %terminationInfo = %terminationList:findNextItem (eq(custId, %custid)
	%terminationList:findNextItem (eq(custId, %custid)
	... process the termination info		... process the termination info
	[[catch]] itemNotFound		[[catch]] itemNotFound

JAL2 at 19:20, 8 August 2011

2011-08-08T19:20:42Z

← Older revision		Revision as of 19:20, 8 August 2011
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	<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.		<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.
	</td></tr>		</td></tr>
	<tr><th><var>%(ItemNotFound)</var></th><td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors\|Constructor]]</var>. ~~<var>New</var> can also be invoked via~~ an <var>ItemNotFound</var> ~~object variable, which may be~~ <var>~~Null~~</var>.</td></tr>		<tr><th><var>%(ItemNotFound)</var></th>
			<td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors\|Constructor]]</var>. See [[#Usage notes\|"Usage notes"]], below, for more information about invoking an <var>ItemNotFound</var> <var>Constructor</var>.</td></tr>
	</table>		</table>

			<h3>Usage notes</h3>
			<ul>
			<li>As described in [[Object variables#Using New or other Constructors\|"Using New or other Constructors"]], <var>New</var> can be invoked with no object, with an explicit class name, or with an object variable in the class, even if that object is <var>Null</var>:<p class="code">%itemnfd = new

			%itemnfd = %(ItemNotFound):new

			%itemnfd = %itemnfd:new
			</p>
			</ul>

	[[Category:System exception classes]]		[[Category:System exception classes]]

JAL2 at 19:05, 8 August 2011

2011-08-08T19:05:57Z

← Older revision		Revision as of 19:05, 8 August 2011
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	This exception class has no properties. It is simply a notification that a valid search found no items that met the selection criterion.		This exception class has no properties. It is simply a notification that a valid search found no items that met the selection criterion.

	The class's only method is the <var>[[New_(ItemNotFound_constructor)\|New]]</var> constructor, which you would typically use with a <var class="product">User Language</var> [[Throw]] statement to produce an <var>ItemNotFound</var> exception. For example:		The class's only method is the <var>[[New_(ItemNotFound_constructor)\|New]]</var> constructor, which you would typically use with a <var class="product">User Language</var> <var>[[Throw statement\|Throw]]</var> statement to produce an <var>ItemNotFound</var> exception yourself.
			For example:
	<p class="code">throw %(itemNotFound):new		<p class="code">throw %(itemNotFound):new
	</p>		</p>

	Remember that ~~catching~~ an exception ~~requires a~~ <var>[[Catch statement\|Catch]]</var> statement; if an exception condition occurs outside a		Remember that you catch an exception with the <var>[[Catch statement\|Catch]]</var> statement; if an exception condition occurs outside a
	<var>Catch</var> for it, the request is cancelled.		<var>Catch</var> for it, the request is cancelled.
	For example, if you expect one or no matches from your search, you might specify a block like the following:		For example, if you expect one or no matches from your search, you might specify a block like the following:

JAL2 at 21:08, 27 July 2011

2011-07-27T21:08:39Z

← Older revision		Revision as of 21:08, 27 July 2011
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	<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.		<td>An <var>ItemNotFound</var> %variable which will refer to the newly created object.
	</td></tr>		</td></tr>
	<tr><th><var>%(ItemNotFound)</var></th><td>The class name in parentheses denotes a ~~shared method~~. <var>New</var> can also be invoked via an <var>ItemNotFound</var> object variable, which may be <var>Null</var>.</td></tr>		<tr><th><var>%(ItemNotFound)</var></th><td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors\|Constructor]]</var>. <var>New</var> can also be invoked via an <var>ItemNotFound</var> object variable, which may be <var>Null</var>.</td></tr>
	</table>		</table>


	[[Category:System exception classes]]		[[Category:System exception classes]]