Example usage for javax.script Invocable getInterface

Introduction

In this page you can find the example usage for javax.script Invocable getInterface.

Prototype

public <T> T getInterface(Object thiz, Class<T> clasz);

Source Link

Document

Returns an implementation of an interface using member functions of a scripting object compiled in the interpreter.

Usage

From source file:org.apache.nifi.processors.script.InvokeScriptedProcessor.java

/**
 * Reloads the script Processor. This must be called within the lock.
 *
 * @param scriptBody An input stream associated with the script content
 * @return Whether the script was successfully reloaded
 *///  www  .j  a  v  a 2  s.  c  o  m
private boolean reloadScript(final String scriptBody) {
    // note we are starting here with a fresh listing of validation
    // results since we are (re)loading a new/updated script. any
    // existing validation results are not relevant
    final Collection<ValidationResult> results = new HashSet<>();

    try {
        // get the engine and ensure its invocable
        if (scriptEngine instanceof Invocable) {
            final Invocable invocable = (Invocable) scriptEngine;

            // Find a custom configurator and invoke their eval() method
            ScriptEngineConfigurator configurator = scriptingComponentHelper.scriptEngineConfiguratorMap
                    .get(scriptingComponentHelper.getScriptEngineName().toLowerCase());
            if (configurator != null) {
                configurator.eval(scriptEngine, scriptBody, scriptingComponentHelper.getModules());
            } else {
                // evaluate the script
                scriptEngine.eval(scriptBody);
            }

            // get configured processor from the script (if it exists)
            final Object obj = scriptEngine.get("processor");
            if (obj != null) {
                final ComponentLog logger = getLogger();

                try {
                    // set the logger if the processor wants it
                    invocable.invokeMethod(obj, "setLogger", logger);
                } catch (final NoSuchMethodException nsme) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Configured script Processor does not contain a setLogger method.");
                    }
                }

                // record the processor for use later
                final Processor scriptProcessor = invocable.getInterface(obj, Processor.class);
                processor.set(scriptProcessor);

                if (scriptProcessor != null) {
                    try {
                        scriptProcessor.initialize(new ProcessorInitializationContext() {
                            @Override
                            public String getIdentifier() {
                                return InvokeScriptedProcessor.this.getIdentifier();
                            }

                            @Override
                            public ComponentLog getLogger() {
                                return logger;
                            }

                            @Override
                            public ControllerServiceLookup getControllerServiceLookup() {
                                return InvokeScriptedProcessor.super.getControllerServiceLookup();
                            }

                            @Override
                            public NodeTypeProvider getNodeTypeProvider() {
                                return InvokeScriptedProcessor.super.getNodeTypeProvider();
                            }

                            @Override
                            public String getKerberosServicePrincipal() {
                                return InvokeScriptedProcessor.this.kerberosServicePrincipal;
                            }

                            @Override
                            public File getKerberosServiceKeytab() {
                                return InvokeScriptedProcessor.this.kerberosServiceKeytab;
                            }

                            @Override
                            public File getKerberosConfigurationFile() {
                                return InvokeScriptedProcessor.this.kerberosConfigFile;
                            }
                        });
                    } catch (final Exception e) {
                        logger.error("Unable to initialize scripted Processor: " + e.getLocalizedMessage(), e);
                        throw new ProcessException(e);
                    }
                }
            } else {
                throw new ScriptException("No processor was defined by the script.");
            }
        }

    } catch (final Exception ex) {
        final ComponentLog logger = getLogger();
        final String message = "Unable to load script: " + ex.getLocalizedMessage();

        logger.error(message, ex);
        results.add(new ValidationResult.Builder().subject("ScriptValidation").valid(false)
                .explanation("Unable to load script due to " + ex.getLocalizedMessage())
                .input(scriptingComponentHelper.getScriptPath()).build());
    }

    // store the updated validation results
    validationResults.set(results);

    // return whether there was any issues loading the configured script
    return results.isEmpty();
}

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