WriteError class: Difference between revisions

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This page is [[under construction]].
__NOTOC__
__NOTOC__
WriteError exceptions are typically thrown by the [[?? (WriteError function)|Parse function]] in the [[WriteError class]] when there is an error parsing record data.
<var>WriteError</var> exceptions are thrown by the <var>Close</var>, <var>WriteBlock</var>, <var>WriteRecord</var>, and <var>WriteRecords</var> methods in the [[Dataset class]] if they encounter a full dataset. The problem with this approach is if the dataset fills on your last write or maybe on the Close (since Close flushes buffers and checks pending writes) you might never notice that your dataset filled up. Silently, allowing a dataset to be truncated doesn’t seem like a good idea.
   
   
To create a <var>WriteError</var> exception yourself, you typically use a SOUL <var>[[Exceptions#Using the Throw statement|Throw]]</var> statement with an <var>WriteError</var> <var>[[New_(WriteError_constructor)|New]]</var> constructor. This statement must be issued from within a method, and it can only be caught by the code that calls the method. For example, the following statement throws a <var>WriteError</var> exception:
To create a <var>WriteError</var> exception yourself, you typically use a SOUL <var>[[Exceptions#Using the Throw statement|Throw]]</var> statement with an <var>WriteError</var> <var>[[New_(WriteError_constructor)|New]]</var> constructor. This statement must be issued from within a method, and it can only be caught by the code that calls the method. For example, the following statement throws a <var>WriteError</var> exception:
<p class="code">throw %(WriteError):new(characterPosition=%pos)
<p class="code">throw %(WriteError):new(returnCode=%rc)
</p>
</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 canceled.
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 canceled.
   
   
The <var>WriteError</var> class, like the WriteError class is available as of <var class="product">Model 204</var> 7.6.
The <var>WriteError</var> class is available as of <var class="product">Model 204</var> 7.7.
   
   
==The WriteError methods==
==The WriteError methods==
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The methods in the class are described in the subsections that follow. In addition:
The methods in the class are described in the subsections that follow. In addition:
<ul>
<ul>
<li>[[Notation conventions for methods|"Notation conventions for methods"]] has information
<li>[[Notation conventions for methods]] has information
about the conventions followed.
about the conventions followed. </li>
<li>[[WriteError methods syntax|"WriteError methods syntax"]] is a single page that contains the syntax diagrams of all the methods in the class.
 
<li>[[WriteError methods syntax]] is a single page that contains the syntax diagrams of all the methods in the class. </li>
</ul>
</ul>
==CharacterPosition property==
 
{{Template:WriteError:CharacterPosition subtitle}}
==ReturnCode property==
{{Template:WriteError:ReturnCode subtitle}}
   
   
This <var>[[Classes and Objects#readWrite|ReadOnly]]</var> property returns a number that indicates the character position (unicode characters are each two bytes long) in the unicode string being parsed where the error was detected.
This <var>[[Classes and Objects#readWrite|ReadOnly]]</var> property returns a number that indicates the type of error encountered.  
 
===Syntax===
===Syntax===
{{Template:WriteError:CharacterPosition syntax}}
{{Template:WriteError:ReturnCode syntax}}
   
   
====Syntax terms====
====Syntax terms====
<table class="syntaxTable">
<table>
<tr><th>%number</th>
<tr><th>%number</th>
<td>The character position in the input unicode string where the parse error was detected.</td></tr>
<td>An I/O error return code. The most likely codes are:
<p class="codeInTable"> 4  Permanent I/O error
10  Offload process failed
12  File full condition </p>
</td></tr>
   
   
<tr><th>jsonParseError</th>
<tr><th>writeError</th>
<td>A reference to an instance of a <var>[[WriteError_class|WriteError]]</var> object.</td></tr>
</table>
==Description property==
{{Template:WriteError:Description subtitle}}
This <var>[[Classes and Objects#readWrite|ReadOnly]]</var> property returns a string that describes the error that was encountered while parsing the JSON data.
===Syntax===
{{Template:WriteError:Description syntax}}
====Syntax terms====
<table class="syntaxTable">
<tr><th>%string</th>
<td>Text the describes the error that was encountered while parsing JSON data.</td></tr>
<tr><th>jsonParseError</th>
<td>A reference to an instance of a <var>[[WriteError_class|WriteError]]</var> object.</td></tr>
<td>A reference to an instance of a <var>[[WriteError_class|WriteError]]</var> object.</td></tr>
</table>
</table>
   
   
==New constructor==
==New constructor==
{{Template:WriteError:New subtitle}}
{{Template:WriteError:New subtitle}}
   
   
This <var>Constructor</var> generates an instance of a <var>[[WriteError_class|WriteError]]</var> exception. The <var>New</var> method format follows:
This <var>Constructor</var> generates an instance of a <var>[[WriteError_class|WriteError]]</var> exception.  
 
===Syntax===
===Syntax===
{{Template:WriteError:New syntax}}
{{Template:WriteError:New syntax}}
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====Syntax terms====
====Syntax terms====
<table>
<table>
<tr><th>%jsonParseError</th><td>A reference to an instance of a <var>WriteError</var> object.</td></tr>
<tr><th>%writeError</th>
<tr><th><var>[%(WriteError):]</var></th><td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors|Constructor]]</var>.</td></tr>
<td>A reference to an instance of a <var>WriteError</var> object.</td></tr>
<tr><th>number</th><td>The character position in the input unicode string where the parse error was detected.</td></tr>
 
<tr><th>string</th><td>Text that describes the error. It must be 127 characters long or less.</td></tr>
<tr><th><var>[%(WriteError):]</var></th>
<td>The class name in parentheses denotes a <var>[[Notation conventions for methods#Constructors|Constructor]]</var>.</td></tr>
 
<tr><th>number</th>
<td>A <var>ReturnCode</var> property value that indicates the type of error encountered.</td></tr>
</table>
</table>
===Usage notes===
<ul>
<li>Since the WriteError exception does not provide
</ul>


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

Revision as of 16:47, 9 August 2016

WriteError exceptions are thrown by the Close, WriteBlock, WriteRecord, and WriteRecords methods in the Dataset class if they encounter a full dataset. The problem with this approach is if the dataset fills on your last write or maybe on the Close (since Close flushes buffers and checks pending writes) you might never notice that your dataset filled up. Silently, allowing a dataset to be truncated doesn’t seem like a good idea.

To create a WriteError exception yourself, you typically use a SOUL Throw statement with an WriteError New constructor. This statement must be issued from within a method, and it can only be caught by the code that calls the method. For example, the following statement throws a WriteError exception:

throw %(WriteError):new(returnCode=%rc)

Remember that you catch an exception with the Catch statement. If an exception condition occurs outside a Catch for it, the request is canceled.

The WriteError class is available as of Model 204 7.7.

The WriteError methods

The following are the available WriteError class methods.

MethodDescription
NewCreate a new WriteError object
ReturnCodeReturn code from failed write

The methods in the class are described in the subsections that follow. In addition:

ReturnCode property

Return code from failed write (WriteError class)

This ReadOnly property returns a number that indicates the type of error encountered.

Syntax

%number = writeError:ReturnCode

Syntax terms

%number An I/O error return code. The most likely codes are:

4 Permanent I/O error 10 Offload process failed 12 File full condition

writeError A reference to an instance of a WriteError object.


New constructor

Create a new WriteError object (WriteError class)

This Constructor generates an instance of a WriteError exception.

Syntax

%writeError = [%(WriteError):]New( ReturnCode= number)

Syntax terms

%writeError A reference to an instance of a WriteError object.
[%(WriteError):] The class name in parentheses denotes a Constructor.
number A ReturnCode property value that indicates the type of error encountered.
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