Examples with MVELEvalExpression org.drools.core.base.mvel.MVELEvalExpression used on opensource projects

Example 1 with MVELEvalExpression

use of org.drools.core.base.mvel.MVELEvalExpression in project drools by kiegroup.

the class MVELEvalBuilderTest method testSimpleExpression.

@Test
public void testSimpleExpression() {
    InternalKnowledgePackage pkg = new KnowledgePackageImpl("pkg1");
    final RuleDescr ruleDescr = new RuleDescr("rule 1");
    KnowledgeBuilderImpl pkgBuilder = new KnowledgeBuilderImpl(pkg);
    final KnowledgeBuilderConfigurationImpl conf = pkgBuilder.getBuilderConfiguration();
    DialectCompiletimeRegistry dialectRegistry = pkgBuilder.getPackageRegistry(pkg.getName()).getDialectCompiletimeRegistry();
    MVELDialect mvelDialect = (MVELDialect) dialectRegistry.getDialect("mvel");
    final RuleBuildContext context = new RuleBuildContext(pkgBuilder, ruleDescr, dialectRegistry, pkg, mvelDialect);
    final InstrumentedDeclarationScopeResolver declarationResolver = new InstrumentedDeclarationScopeResolver();
    final InternalReadAccessor extractor = store.getReader(Cheese.class, "price");
    final Pattern pattern = new Pattern(0, new ClassObjectType(int.class));
    final Declaration declaration = new Declaration("a", extractor, pattern);
    final Map map = new HashMap();
    map.put("a", declaration);
    declarationResolver.setDeclarations(map);
    context.setDeclarationResolver(declarationResolver);
    final EvalDescr evalDescr = new EvalDescr();
    evalDescr.setContent("a == 10");
    final MVELEvalBuilder builder = new MVELEvalBuilder();
    final EvalCondition eval = (EvalCondition) builder.build(context, evalDescr);
    ((MVELEvalExpression) eval.getEvalExpression()).compile((MVELDialectRuntimeData) pkgBuilder.getPackageRegistry(pkg.getName()).getDialectRuntimeRegistry().getDialectData("mvel"));
    InternalKnowledgeBase kBase = KnowledgeBaseFactory.newKnowledgeBase();
    StatefulKnowledgeSessionImpl ksession = (StatefulKnowledgeSessionImpl) kBase.newKieSession();
    MockLeftTupleSink sink = new MockLeftTupleSink();
    final Cheese cheddar = new Cheese("cheddar", 10);
    final InternalFactHandle f0 = (InternalFactHandle) ksession.insert(cheddar);
    final LeftTupleImpl tuple = new LeftTupleImpl(f0, sink, true);
    f0.removeLeftTuple(tuple);
    Object evalContext = eval.createContext();
    assertTrue(eval.isAllowed(tuple, ksession, evalContext));
    cheddar.setPrice(9);
    ksession.update(f0, cheddar);
    assertFalse(eval.isAllowed(tuple, ksession, evalContext));
}

Example 2 with MVELEvalExpression

use of org.drools.core.base.mvel.MVELEvalExpression in project drools by kiegroup.

the class MVELEvalBuilder method build.

/**
 * Builds and returns an Eval Conditional Element
 *
 * @param context The current build context
 * @param descr The Eval Descriptor to build the eval conditional element from
 *
 * @return the Eval Conditional Element
 */
public RuleConditionElement build(final RuleBuildContext context, final BaseDescr descr, final Pattern prefixPattern) {
    boolean typesafe = context.isTypesafe();
    // it must be an EvalDescr
    final EvalDescr evalDescr = (EvalDescr) descr;
    try {
        MVELDialect dialect = (MVELDialect) context.getDialect("mvel");
        Map<String, Declaration> decls = context.getDeclarationResolver().getDeclarations(context.getRule());
        AnalysisResult analysis = context.getDialect().analyzeExpression(context, evalDescr, evalDescr.getContent(), new BoundIdentifiers(DeclarationScopeResolver.getDeclarationClasses(decls), context));
        final BoundIdentifiers usedIdentifiers = analysis.getBoundIdentifiers();
        int i = usedIdentifiers.getDeclrClasses().keySet().size();
        Declaration[] previousDeclarations = new Declaration[i];
        i = 0;
        for (String id : usedIdentifiers.getDeclrClasses().keySet()) {
            previousDeclarations[i++] = decls.get(id);
        }
        Arrays.sort(previousDeclarations, SortDeclarations.instance);
        MVELCompilationUnit unit = dialect.getMVELCompilationUnit((String) evalDescr.getContent(), analysis, previousDeclarations, null, null, context, "drools", KnowledgeHelper.class, false, MVELCompilationUnit.Scope.EXPRESSION);
        final EvalCondition eval = new EvalCondition(previousDeclarations);
        MVELEvalExpression expr = new MVELEvalExpression(unit, dialect.getId());
        eval.setEvalExpression(KiePolicyHelper.isPolicyEnabled() ? new SafeEvalExpression(expr) : expr);
        MVELDialectRuntimeData data = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData("mvel");
        data.addCompileable(eval, expr);
        expr.compile(data, context.getRule());
        return eval;
    } catch (final Exception e) {
        copyErrorLocation(e, evalDescr);
        context.addError(new DescrBuildError(context.getParentDescr(), evalDescr, e, "Unable to build expression for 'eval':" + e.getMessage() + " '" + evalDescr.getContent() + "'"));
        return null;
    } finally {
        context.setTypesafe(typesafe);
    }
}