private void createResultBind(
final Pattern pattern,
int index,
InternalReadAccessor arrayReader,
AccumulateFunctionCallDescr fc,
AccumulateFunction function) {
// bind function result on the result pattern
Declaration declr = pattern.addDeclaration(fc.getBind());
Class<?> type = function.getResultType();
// this bit is different, notice its the ArrayElementReader that we wire up to, not the
// declaration.
ArrayElementReader reader = new ArrayElementReader(arrayReader, index, type);
declr.setReadAccessor(reader);
}
private Accumulator[] buildExternalFunctions(
final RuleBuildContext context,
final AccumulateDescr accumDescr,
MVELDialect dialect,
Map<String, Declaration> decls,
Map<String, Declaration> sourceOuterDeclr,
BoundIdentifiers boundIds,
boolean readLocalsFromTuple) {
Accumulator[] accumulators;
List<AccumulateFunctionCallDescr> functions = accumDescr.getFunctions();
accumulators = new Accumulator[functions.size()];
// creating the custom array reader
InternalReadAccessor arrayReader = new SelfReferenceClassFieldReader(Object[].class, "this");
int index = 0;
Pattern pattern = (Pattern) context.getBuildStack().peek();
for (AccumulateFunctionCallDescr func : functions) {
// build an external function executor
AccumulateFunction function =
context.getConfiguration().getAccumulateFunction(func.getFunction());
if (function == null) {
context.addError(
new DescrBuildError(
accumDescr,
context.getRuleDescr(),
null,
"Unknown accumulate function: '"
+ func.getFunction()
+ "' on rule '"
+ context.getRuleDescr().getName()
+ "'. All accumulate functions must be registered before building a resource."));
return null;
}
// if there is a binding, create the binding
if (func.getBind() != null) {
if (pattern.getDeclaration(func.getBind()) != null) {
context.addError(
new DescrBuildError(
context.getParentDescr(),
accumDescr,
null,
"Duplicate declaration for variable '"
+ func.getBind()
+ "' in the rule '"
+ context.getRule().getName()
+ "'"));
} else {
createResultBind(pattern, index, arrayReader, func, function);
}
}
final AnalysisResult analysis =
dialect.analyzeExpression(
context,
accumDescr,
func.getParams().length > 0 ? func.getParams()[0] : "\"\"",
boundIds);
MVELCompilationUnit unit =
dialect.getMVELCompilationUnit(
func.getParams().length > 0 ? func.getParams()[0] : "\"\"",
analysis,
getUsedDeclarations(decls, analysis),
getUsedDeclarations(sourceOuterDeclr, analysis),
null,
context,
"drools",
KnowledgeHelper.class,
readLocalsFromTuple);
accumulators[index++] = new MVELAccumulatorFunctionExecutor(unit, function);
}
return accumulators;
}