Interface JxltEngine.Template
- Enclosing class:
JxltEngine
The source text is parsed considering each line beginning with '$$' (as default pattern) as JEXL script code and all others as Unified JEXL expressions; those expressions will be invoked from the script during evaluation and their output gathered through a writer. It is thus possible to use looping or conditional construct "around" expressions generating output.
For instance:$$ for (var x : [1, 3, 5, 42, 169]) { $$ if (x == 42) { Life, the universe, and everything $$ } else if (x > 42) { The value $(x} is over forty-two $$ } else { The value ${x} is under forty-two $$ } $$}
Will evaluate as:
The value 1 is under forty-two The value 3 is under forty-two The value 5 is under forty-two Life, the universe, and everything The value 169 is over forty-two
During evaluation, the template context exposes its writer as '$jexl' which is safe to use in this case. This allows writing directly through the writer without adding new-lines as in:
$$ for(var cell : cells) { $jexl.print(cell); $jexl.print(';') }
A template is expanded as one JEXL script and a list of template expressions; each template expression is being replaced in the script by a call to jexl:print(expr) (the expr is in fact the expr number in the template). This integration uses a specialized JexlContext (TemplateContext) that serves as a namespace (for jexl:) and stores the template expression array and the writer (java.io.Writer) that the 'jexl:print(...)' delegates the output generation to.
- Since:
- 3.0
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Method Summary
Modifier and TypeMethodDescriptionasString()Recreate the template source from its inner components.voidevaluate(JexlContext context, Writer writer) Evaluates this template.voidevaluate(JexlContext context, Writer writer, Object... args) Evaluates this template.String[]Gets the list of parameters expected by this template.Gets this script pragmas.Gets the list of variables accessed by this template.prepare(JexlContext context) Prepares this template by expanding any contained deferred TemplateExpression.
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Method Details
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asString
Recreate the template source from its inner components.- Returns:
- the template source rewritten
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evaluate
Evaluates this template.- Parameters:
context- the context to use during evaluationwriter- the writer to use for output
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evaluate
Evaluates this template.- Parameters:
context- the context to use during evaluationwriter- the writer to use for outputargs- the arguments
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getParameters
String[] getParameters()Gets the list of parameters expected by this template.- Returns:
- the parameter names array
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getPragmas
Gets this script pragmas.- Returns:
- the (non null, may be empty) pragmas map
- Since:
- 3.1
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getVariables
Set<List<String>> getVariables()Gets the list of variables accessed by this template.This method will visit all nodes of the sub-expressions and extract all variables whether they are written in 'dot' or 'bracketed' notation. (a.b is equivalent to a['b']).
- Returns:
- the set of variables, each as a list of strings (ant-ish variables use more than 1 string) or the empty set if no variables are used
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prepare
Prepares this template by expanding any contained deferred TemplateExpression.- Parameters:
context- the context to prepare against- Returns:
- the prepared version of the template
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