Regular Expressions Patterns for TokXMLFile
To control what is extracted from XML type files the TokXMLFile class uses a set of regular expressions. The regular expressions are presented in a properties file specified when the Tok class is called. This in turn is specified in the L10NProcess.xml file or through the use of a command line parameter. The easiest way to provide the appropriate properties file name is to use the project.properties file. If no XMLPROPFILE property is set then the default xml.properties file will be used.
The project.properties file and the properties file that contains the regular expressions (default is xml.properties) must be placed in the project directory.
Some design considerations used during development of the TokXMLFile class are:
- the patterns can vary from one project to another
- the project patterns properties file must be specified by the user at run time
- the project patterns properties file will be controlled by the Ant process files
- if no project patterns properties file is supplied the default pattern properties file will be used
- there is no affect on the Detok process
Some assumptions used during design and implementation of TokXMLFile are:
- all text is properly coded XML
- the extracted item is a standard Regular Expression pattern contained between ( and )
- up to nine items can be extracted in a single pattern
- patterns can be combined if needed
- patterns must be specified in order from most specific to most general
- all patterns will be matched
- extracted strings that contain only whitespace or a token will be ignored and all other extracted strings will be replaced by a token
- the regular expression syntax is AWK syntax
Some example regular expressions are:
- Select the value of attribute a2 when the value of attribute a1 is x and the element is e.
- Select the value of attribute a when the element is e.
- Select the text for the element when the element is e.
- Select the value of attribute a.
- Select the text for any element. (This will be the default pattern supplied with the tool kit.)
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by Bill Rich