org.drools.compiler.lang

Interface Expander

All Known Implementing Classes:

DefaultExpander

public interface Expander

Expanders are extension points for expanding expressions in DRL at parse time. This is just-in-time translation, or macro expansion, or whatever you want. The important thing is that it happens at the last possible moment, so any errors in expansion are included in the parsers errors. Just-in-time expansions may include complex pre-compilers, or just macros, and everything in between. Expanders should ideally not make presumptions on any embedded semantic language. For instance, java aware pre processing should be done in drools-java semantic module, not in the parser itself. Expanders should be reusable across semantic languages.

Method Summary

Modifier and Type	Method and Description
void	addDSLMapping(DSLMapping mapping) Add the new mapping to this expander.
String	expand(Reader drl) Expands (process) the expression Just-In-Time for the parser.
String	expand(String source) Expands (process) the expression Just-In-Time for the parser.
List<ExpanderException>	getErrors() Returns the list of errors from the last expansion made
boolean	hasErrors() Returns true in case the last expansion had any errors

Method Detail

expand

String expand(Reader drl)
       throws IOException

Expands (process) the expression Just-In-Time for the parser. If the source is not meant to be expanded, or if no appropriate match was found for expansion, it will echo back the same expression.

Parameters:

drl - the source code to be pre-processed

Returns:

source code after running pre-processors

Throws:

IOException

expand

String expand(String source)

Expands (process) the expression Just-In-Time for the parser. If the source is not meant to be expanded, or if no appropriate match was found for expansion, it will echo back the same expression.

Parameters:

source - the source code to be expanded

Returns:

source code after running pre-processors

addDSLMapping

void addDSLMapping(DSLMapping mapping)

Add the new mapping to this expander.

Parameters:

mapping -

getErrors

List<ExpanderException> getErrors()

Returns the list of errors from the last expansion made

Returns:

A list of ExpanderException

hasErrors

boolean hasErrors()

Returns true in case the last expansion had any errors

Returns: