Examples with MVELDataProvider org.drools.core.base.dataproviders.MVELDataProvider used on opensource projects

Example 1 with MVELDataProvider

use of org.drools.core.base.dataproviders.MVELDataProvider in project drools by kiegroup.

the class MVELFromBuilder method build.

public RuleConditionElement build(final RuleBuildContext context, final BaseDescr descr, final Pattern prefixPattern) {
    String text = ((FromDescr) descr).getExpression();
    Optional<EntryPointId> entryPointId = context.getEntryPointId(text);
    if (entryPointId.isPresent()) {
        return entryPointId.get();
    }
    // This builder is re-usable in other dialects, so specify by name
    MVELDialect dialect = (MVELDialect) context.getDialect("mvel");
    boolean typeSafe = context.isTypesafe();
    if (!dialect.isStrictMode()) {
        context.setTypesafe(false);
    }
    try {
        Map<String, Declaration> decls = context.getDeclarationResolver().getDeclarations(context.getRule());
        AnalysisResult analysis = dialect.analyzeExpression(context, descr, text, new BoundIdentifiers(DeclarationScopeResolver.getDeclarationClasses(decls), context));
        if (analysis == null) {
            // something bad happened
            return null;
        }
        Class<?> returnType = ((MVELAnalysisResult) analysis).getReturnType();
        if (prefixPattern != null && !prefixPattern.isCompatibleWithFromReturnType(returnType)) {
            context.addError(new DescrBuildError(descr, context.getRuleDescr(), null, "Pattern of type: '" + prefixPattern.getObjectType() + "' on rule '" + context.getRuleDescr().getName() + "' is not compatible with type " + returnType.getCanonicalName() + " returned by source"));
            return null;
        }
        final BoundIdentifiers usedIdentifiers = analysis.getBoundIdentifiers();
        final Declaration[] declarations = new Declaration[usedIdentifiers.getDeclrClasses().size()];
        int j = 0;
        for (String str : usedIdentifiers.getDeclrClasses().keySet()) {
            declarations[j++] = decls.get(str);
        }
        Arrays.sort(declarations, SortDeclarations.instance);
        MVELCompilationUnit unit = dialect.getMVELCompilationUnit(text, analysis, declarations, null, null, context, "drools", KnowledgeHelper.class, false, MVELCompilationUnit.Scope.CONSEQUENCE);
        MVELDataProvider dataProvider = new MVELDataProvider(unit, context.getDialect().getId());
        From from = new From(dataProvider);
        from.setResultPattern(prefixPattern);
        MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData("mvel");
        data.addCompileable(from, dataProvider);
        dataProvider.compile(data, context.getRule());
        return from;
    } catch (final Exception e) {
        DialectUtil.copyErrorLocation(e, descr);
        context.addError(new DescrBuildError(context.getParentDescr(), descr, null, "Unable to build expression for 'from' : " + e.getMessage() + " '" + text + "'"));
        return null;
    } finally {
        context.setTypesafe(typeSafe);
    }
}