Examples with ScriptBlock org.drools.model.functions.ScriptBlock used on opensource projects

Example 1 with ScriptBlock

use of org.drools.model.functions.ScriptBlock in project drools by kiegroup.

the class MVELConsequence method evaluate.

@Override
public void evaluate(KnowledgeHelper knowledgeHelper, WorkingMemory workingMemory) throws Exception {
    // same as lambda consequence...
    Tuple tuple = knowledgeHelper.getTuple();
    Declaration[] declarations = ((RuleTerminalNode) knowledgeHelper.getMatch().getTuple().getTupleSink()).getRequiredDeclarations();
    Variable[] vars = consequence.getVariables();
    // ...but the facts are association of Variable and its value, preserving order.
    Map<Variable, Object> facts = new LinkedHashMap<>();
    int declrCounter = 0;
    for (Variable var : vars) {
        if (var.isFact()) {
            Declaration declaration = declarations[declrCounter++];
            InternalFactHandle fh = tuple.get(declaration);
            facts.put(var, declaration.getValue((InternalWorkingMemory) workingMemory, fh.getObject()));
        } else {
            facts.put(var, workingMemory.getGlobal(var.getName()));
        }
    }
    ScriptBlock scriptBlock = null;
    try {
        scriptBlock = (ScriptBlock) consequence.getBlock();
    } catch (ClassCastException e) {
        throw new RuntimeException("I tried to access a ScriptBlock but it was not. So something is thinking is a MVEL consequence but did not set the MVEL script textual representation", e);
    }
    String originalRHS = scriptBlock.getScript();
    String name = context.getRule().getPackageName() + "." + context.getRule().getName();
    String expression = MVELConsequenceBuilder.processMacros(originalRHS);
    String[] globalIdentifiers = new String[] {};
    String[] default_inputIdentifiers = new String[] { "this", "drools", "kcontext", "rule" };
    String[] inputIdentifiers = Stream.concat(Arrays.asList(default_inputIdentifiers).stream(), facts.entrySet().stream().map(kv -> kv.getKey().getName())).collect(Collectors.toList()).toArray(new String[] {});
    String[] default_inputTypes = new String[] { "org.drools.core.spi.KnowledgeHelper", "org.drools.core.spi.KnowledgeHelper", "org.drools.core.spi.KnowledgeHelper", "org.kie.api.definition.rule.Rule" };
    String[] inputTypes = Stream.concat(Arrays.asList(default_inputTypes).stream(), facts.entrySet().stream().map(kv -> kv.getKey().getType().getName())).collect(Collectors.toList()).toArray(new String[] {});
    // ^^ please notice about inputTypes, it is to use the Class.getName(), because is later used by the Classloader internally in MVEL to load the class,
    // do NOT replace with getCanonicalName() otherwise inner classes will not be loaded correctly.
    int languageLevel = 4;
    boolean strictMode = true;
    boolean readLocalsFromTuple = false;
    EvaluatorWrapper[] operators = new EvaluatorWrapper[] {};
    Declaration[] previousDeclarations = new Declaration[] {};
    Declaration[] localDeclarations = new Declaration[] {};
    String[] otherIdentifiers = new String[] {};
    MVELCompilationUnit cu = new MVELCompilationUnit(name, expression, globalIdentifiers, operators, previousDeclarations, localDeclarations, otherIdentifiers, inputIdentifiers, inputTypes, languageLevel, strictMode, readLocalsFromTuple);
    // TODO unfortunately the MVELDialectRuntimeData would be the one of compile time
    // the one from runtime is not helpful, in fact the dialect registry for runtime is empty:
    // MVELDialectRuntimeData runtimeData = (MVELDialectRuntimeData) context.getPkg().getDialectRuntimeRegistry().getDialectData("mvel");
    MVELDialectRuntimeData runtimeData = new MVELDialectRuntimeData();
    // this classloader will be used by the CompilationUnit to load the imports.
    runtimeData.onAdd(null, Thread.currentThread().getContextClassLoader());
    runtimeData.addPackageImport(context.getPkg().getName());
    runtimeData.addPackageImport("java.lang");
    // therefore we assume for the ScriptBlock all available KBPackages are the default available and imported for the scope of the Script itself.
    for (KiePackage kp : context.getKnowledgePackages()) {
        if (!kp.getName().equals(context.getPkg().getName())) {
            runtimeData.addPackageImport(kp.getName());
        }
    }
    // sometimes here it was passed as a 2nd argument a String?? similar to `rule R in file file.drl`
    Serializable cuResult = cu.getCompiledExpression(runtimeData);
    ExecutableStatement compiledExpression = (ExecutableStatement) cuResult;
    // TODO the part above up to the ExecutableStatement compiledExpression should be cached.
    Map<String, Object> mvelContext = new HashMap<>();
    mvelContext.put("this", knowledgeHelper);
    mvelContext.put("drools", knowledgeHelper);
    mvelContext.put("kcontext", knowledgeHelper);
    mvelContext.put("rule", knowledgeHelper.getRule());
    for (Entry<Variable, Object> kv : facts.entrySet()) {
        mvelContext.put(kv.getKey().getName(), kv.getValue());
    }
    CachingMapVariableResolverFactory cachingFactory = new CachingMapVariableResolverFactory(mvelContext);
    VariableResolverFactory factory = cu.getFactory(knowledgeHelper, ((AgendaItem) knowledgeHelper.getMatch()).getTerminalNode().getRequiredDeclarations(), knowledgeHelper.getRule(), knowledgeHelper.getTuple(), null, (InternalWorkingMemory) workingMemory, workingMemory.getGlobalResolver());
    cachingFactory.setNextFactory(factory);
    MVEL.executeExpression(compiledExpression, knowledgeHelper, cachingFactory);
}