Examples with VariableDeclaration org.eclipse.smarthome.model.rule.rules.VariableDeclaration used on opensource projects

Example 1 with VariableDeclaration

use of org.eclipse.smarthome.model.rule.rules.VariableDeclaration in project smarthome by eclipse.

the class RuleContextHelper method getContext.

/**
 * Retrieves the evaluation context (= set of variables) for a rule. The context is shared with all rules in the
 * same model (= rule file).
 *
 * @param rule the rule to get the context for
 * @return the evaluation context
 */
public static synchronized IEvaluationContext getContext(Rule rule, Injector injector) {
    Logger logger = LoggerFactory.getLogger(RuleContextHelper.class);
    RuleModel ruleModel = (RuleModel) rule.eContainer();
    // check if a context already exists on the resource
    for (Adapter adapter : ruleModel.eAdapters()) {
        if (adapter instanceof RuleContextAdapter) {
            return ((RuleContextAdapter) adapter).getContext();
        }
    }
    Provider<IEvaluationContext> contextProvider = injector.getProvider(IEvaluationContext.class);
    // no evaluation context found, so create a new one
    ScriptEngine scriptEngine = injector.getInstance(ScriptEngine.class);
    if (scriptEngine != null) {
        IEvaluationContext evaluationContext = contextProvider.get();
        for (VariableDeclaration var : ruleModel.getVariables()) {
            try {
                Object initialValue = var.getRight() == null ? null : scriptEngine.newScriptFromXExpression(var.getRight()).execute();
                evaluationContext.newValue(QualifiedName.create(var.getName()), initialValue);
            } catch (ScriptExecutionException e) {
                logger.warn("Variable '{}' on rule file '{}' cannot be initialized with value '{}': {}", new Object[] { var.getName(), ruleModel.eResource().getURI().path(), var.getRight().toString(), e.getMessage() });
            }
        }
        ruleModel.eAdapters().add(new RuleContextAdapter(evaluationContext));
        return evaluationContext;
    } else {
        logger.debug("Rule variables of rule {} cannot be evaluated as no scriptengine is available!", ruleModel.eResource().getURI().path());
        return contextProvider.get();
    }
}