I have a math class in a package mypackage.
Now I want to import this class in MVEL and assign values to its property and access its method.
I have written the following code but its giving error as
Exception in thread "main" [Error: unknown class or illegal statement:
^
Code is
ParserContext context = new ParserContext();
context.addImport("math",mypackage.MyMaths.class);//MyMaths.class is public
context.addInput("obj", mypackage.MyMaths.class);
String expression1 = "obj.a == 20";//a is public property
Serializable compiled1 = MVEL.compileExpression(expression1,context);
MVEL.executeExpression(compiled1);
Please try with the below approach.
public static void main(String[] args) {
Map map = new HashMap();
MyMaths mayMaths = new MyMaths();
map.put("obj", mayMaths);
String expression1 = "obj.a = 20";
Serializable compiled1 = MVEL.compileExpression(expression1);
MVEL.executeExpression(compiled1, map);
System.out.println(mayMaths.getA());
}
Output - 20
Related
I have created below JUnit5 parameterized test with ArgumentsSource for loading arguments for the test:
public class DemoModelValidationTest {
public ParamsProvider paramsProvider;
public DemoModelValidationTest () {
try {
paramsProvider = new ParamsProvider();
}
catch (Exception iaex) {
}
}
#ParameterizedTest
#ArgumentsSource(ParamsProvider.class)
void testAllConfigurations(int configIndex, String a) throws Exception {
paramsProvider.executeSimulation(configIndex);
}
}
and the ParamsProvider class looks like below:
public class ParamsProvider implements ArgumentsProvider {
public static final String modelPath = System.getProperty("user.dir") + File.separator + "demoModels";
YAMLDeserializer deserializedYAML;
MetaModelToValidationModel converter;
ValidationRunner runner;
List<Configuration> configurationList;
List<Arguments> listOfArguments;
public ParamsProvider() throws Exception {
configurationList = new ArrayList<>();
listOfArguments = new LinkedList<>();
deserializedYAML = new YAMLDeserializer(modelPath);
deserializedYAML.load();
converter = new MetaModelToValidationModel(deserializedYAML);
runner = converter.convert();
configurationList = runner.getConfigurations();
for (int i = 0; i < configurationList.size(); i++) {
listOfArguments.add(Arguments.of(i, configurationList.get(i).getName()));
}
}
public void executeSimulation(int configListIndex) throws Exception {
final Configuration config = runner.getConfigurations().get(configListIndex);
runner.run(config);
runner.getReporter().consolePrintReport();
}
#Override
public Stream<? extends Arguments> provideArguments(ExtensionContext context) {
return listOfArguments.stream().map(Arguments::of);
// return Stream.of(Arguments.of(0, "Actuator Power"), Arguments.of(1, "Error Logging"));
}}
In the provideArguments() method, the commented out code is working fine, but the first line of code
listOfArguments.stream().map(Arguments::of)
is returning the following error:
org.junit.platform.commons.PreconditionViolationException: Configuration error: You must configure at least one set of arguments for this #ParameterizedTest
I am not sure whether I am having a casting problem for the stream in provideArguments() method, but I guess it somehow cannot map the elements of listOfArguments to the stream, which can finally take the form like below:
Stream.of(Arguments.of(0, "Actuator Power"), Arguments.of(1, "Error Logging"))
Am I missing a proper stream mapping of listOfArguments?
provideArguments(…) is called before your test is invoked.
Your ParamsProvider class is instantiated by JUnit. Whatever you’re doing in desiralizeAndCreateValidationRunnerInstance should be done in the ParamsProvider constructor.
Also you’re already wrapping the values fro deserialised configurations to Arguments and you’re double wrapping them in providesArguments.
Do this:
#Override
public Stream<? extends Arguments> provideArguments(ExtensionContext context) {
return listOfArguments.stream();
}}
I created a custom class that is based on Apache Flink. The following are some parts of the class definition:
public class StreamData {
private StreamExecutionEnvironment env;
private DataStream<byte[]> data ;
private Properties properties;
public StreamData(){
env = StreamExecutionEnvironment.getExecutionEnvironment();
}
public StreamData(StreamExecutionEnvironment e , DataStream<byte[]> d){
env = e ;
data = d ;
}
public StreamData getDataFromESB(String id, int from) {
final Pattern TOPIC = Pattern.compile(id);
Properties properties = new Properties();
properties.setProperty("bootstrap.servers", "localhost:9092");
properties.setProperty("group.id", Long.toString(System.currentTimeMillis()));
properties.setProperty("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
properties.setProperty("value.deserializer", "org.apache.kafka.common.serialization.ByteArrayDeserializer");
properties.put("metadata.max.age.ms", 30000);
properties.put("enable.auto.commit", "false");
if (from == 0)
properties.setProperty("auto.offset.reset", "earliest");
else
properties.setProperty("auto.offset.reset", "latest");
StreamExecutionEnvironment e = StreamExecutionEnvironment.getExecutionEnvironment();
DataStream<byte[]> stream = env
.addSource(new FlinkKafkaConsumer011<>(TOPIC, new AbstractDeserializationSchema<byte[]>() {
#Override
public byte[] deserialize(byte[] bytes) {
return bytes;
}
}, properties));
return new StreamData(e, stream);
}
public void print(){
data.print() ;
}
public void execute() throws Exception {
env.execute() ;
}
Using class StreamData, trying to get some data from Apache Kafka and print them in the main function:
StreamData stream = new StreamData();
stream.getDataFromESB("original_data", 0);
stream.print();
stream.execute();
I got the error:
Exception in thread "main" org.apache.flink.api.common.InvalidProgramException: The implementation of the FlinkKafkaConsumer010 is not serializable. The object probably contains or references non serializable fields.
Caused by: java.io.NotSerializableException: StreamData
As mentioned here, I think it's because of some data type in getDataFromESB function is not serializable. But I don't know how to solve the problem!
Your AbstractDeserializationSchema is an anonymous inner class, which as a result contains a reference to the outer StreamData class which isn't serializable. Either let StreamData implement Serializable, or define your schema as a top-level class.
It seems that you are importing FlinkKafkaConsumer010 in your code but using FlinkKafkaConsumer011. Please use the following dependency in your sbt file:
"org.apache.flink" %% "flink-connector-kafka-0.11" % flinkVersion
All the examples I've seen that use aspect oriented programming for logging either log just class, method name and duration, and if they log parameters and return values they simply use ToString(). I need to have more control over what is logged. For example I want to skip passwords, or in some cases log all properties of an object but in other cases just the id property.
Any suggestions? I looked at AspectJ in Java and Unity interception in C# and could not find a solution.
You could try introducing parameter annotations to augment your parameters with some attributes. One of those attributes could signal to skip logging the parameter, another one could be used to specify a converter class for the string representation.
With the following annotations:
#Documented
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.METHOD)
public #interface Log {
}
#Documented
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.PARAMETER)
public #interface SkipLogging {
}
#Documented
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.PARAMETER)
public #interface ToStringWith {
Class<? extends Function<?, String>> value();
}
the aspect could look like this:
import java.lang.reflect.Parameter;
import java.util.function.Function;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public aspect LoggingAspect {
private final static Logger logger = LoggerFactory.getLogger(LoggingAspect.class);
pointcut loggableMethod(): execution(#Log * *..*.*(..));
before(): loggableMethod() {
MethodSignature signature = (MethodSignature) thisJoinPoint.getSignature();
Parameter[] parameters = signature.getMethod()
.getParameters();
String message = IntStream.range(0, parameters.length)
.filter(i -> this.isLoggable(parameters[i]))
.<String>mapToObj(i -> toString(parameters[i], thisJoinPoint.getArgs()[i]))
.collect(Collectors.joining(", ",
"method execution " + signature.getName() + "(", ")"));
Logger methodLogger = LoggerFactory.getLogger(
thisJoinPointStaticPart.getSignature().getDeclaringType());
methodLogger.debug(message);
}
private boolean isLoggable(Parameter parameter) {
return parameter.getAnnotation(SkipLogging.class) == null;
}
private String toString(Parameter parameter, Object value) {
ToStringWith toStringWith = parameter.getAnnotation(ToStringWith.class);
if (toStringWith != null) {
Class<? extends Function<?, String>> converterClass =
toStringWith.value();
try {
#SuppressWarnings("unchecked")
Function<Object, String> converter = (Function<Object, String>)
converterClass.newInstance();
String str = converter.apply(value);
return String.format("%s='%s'", parameter.getName(), str);
} catch (Exception e) {
logger.error("Couldn't instantiate toString converter for logging "
+ converterClass.getName(), e);
return String.format("%s=<error converting to string>",
parameter.getName());
}
} else {
return String.format("%s='%s'", parameter.getName(), String.valueOf(value));
}
}
}
Test code:
public static class SomethingToStringConverter implements Function<Something, String> {
#Override
public String apply(Something something) {
return "Something nice";
}
}
#Log
public void test(
#ToStringWith(SomethingToStringConverter.class) Something something,
String string,
#SkipLogging Class<?> cls,
Object object) {
}
public static void main(String[] args) {
// execution of this method should log the following message:
// method execution test(something='Something nice', string='some string', object='null')
test(new Something(), "some string", Object.class, null);
}
I used Java 8 Streams API in my answer for it's compactness, you could convert the code to normal Java code if you don't use Java 8 features or need better efficiency. It's just to give you an idea.
I have the following code with a simple class and a method for writing and then reading:
ObjectMapper mapper = new ObjectMapper();
try{
DataStore testOut = new DataStore();
DataStore.Checklist ch1 = testOut.addChecklist();
ch1.SetTitle("Checklist1");
String output = mapper.writeValueAsString(testOut);
JsonNode rootNode = mapper.readValue(output, JsonNode.class);
Map<String,Object> userData = mapper.readValue(output, Map.class);
}
public class DataStore {
public static class Checklist
{
public Checklist()
{
}
private String _title;
public String GetTitle()
{
return _title;
}
public void SetTitle(String title)
{
_title = title;
}
}
//Checklists
private Vector<Checklist> _checklists = new Vector<Checklist>();
public Checklist addChecklist()
{
Checklist ch = new Checklist();
ch.SetTitle("New Checklist");
_checklists.add(ch);
return ch;
}
public Vector<Checklist> getChecklists()
{
return _checklists;
}
public void setChecklists(Vector<Checklist> checklists)
{
_checklists = checklists;
}
}
The line:
String output = mapper.writeValueAsString(testOut);
causes an exception that has had me baffled for hours and about to abandon using this at all.
Any hints are appreciated.
Here is the exception:
No serializer found for class DataStore$Checklist and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) ) (through reference chain: DataStore["checklists"]->java.util.Vector[0])
There are multiple ways to do it, but I will start with what you are doing wrong: your naming of getter and setter method is wrong -- in Java one uses "camel-case", so you should be using "getTitle". Because of this, properties are not found.
Besides renaming methods to use Java-style names, there are alternatives:
You can use annotation JsonProperty("title") for GetTitle(), so that property is recognized
If you don't want the wrapper object, you could alternatively just add #JsonValue for GetTitle(), in which case value used for the whole object would be return value of that method.
The answer seems to be: You can't do that with Json. I've seen comments in the Gson tutorial as well, that state that some serialization just doesn't work. I downloaded XStream and spat it out with XML in a few minutes of work and a lot less construction around what I really wanted to persist. In the process, I was able to delete a lot of code.
I'm using a HeaderColumnNameMappingStrategy to map a csv file with a header into a JavaBean. String values parse fine but any "true" or "false" value in csv doesn't map to JavaBean and I get the following exception from the PropertyDescriptor:
java.lang.IllegalArgumentException: argument type mismatch
The code where it occurs is in CsvToBean, line 64:
protected T processLine(MappingStrategy<T> mapper, String[] line) throws
IllegalAccessException, InvocationTargetException, InstantiationException, IntrospectionException {
T bean = mapper.createBean();
for(int col = 0; col < line.length; col++) {
String value = line[col];
PropertyDescriptor prop = mapper.findDescriptor(col);
if (null != prop) {
Object obj = convertValue(value, prop);
// this is where exception is thrown for a "true" value in csv
prop.getWriteMethod().invoke(bean, new Object[] {obj});
}
}
return bean;
}
protected PropertyEditor getPropertyEditor(PropertyDescriptor desc) throws
InstantiationException, IllegalAccessException {
Class<?> cls = desc.getPropertyEditorClass();
if (null != cls) return (PropertyEditor) cls.newInstance();
return getPropertyEditorValue(desc.getPropertyType());
}
I can confirm (via debugger) that the setter method id correctly retrieved at this point.
The problem occurs in desc.getPropertyEditorClass() since it returns null. I assumed primitive types and its wrappers are supported. Are they not?
I've run into this same issue. The cleanest way is probably to override getPropertyEditor like pritam did above and return a custom PropertyEditor for your particular object. The quick and dirty way would be to override convertValue in anonymous class form, like this:
CsvToBean<MyClass> csvToBean = new CsvToBean<MyClass>(){
#Override
protected Object convertValue(String value, PropertyDescriptor prop) throws InstantiationException,IllegalAccessException {
if (prop.getName().equals("myWhatever")) {
// return an custom object based on the incoming value
return new MyWhatever((String)value);
}
return super.convertValue(value, prop);
}
};
This is working fine for me with OpenCSV 2.3. Good luck!
I resolved this by extending CsvToBean and adding my own PropertyEditors. Turns out opencsv just supports primitive types and no wrappers.
Pritam's answer is great and this is a sample for dealing with datetime format.
PropertyEditorManager.registerEditor(java.util.Date.class, DateEditor.class);
You should write your own editor class like this:
public class DateEditor extends PropertyEditorSupport{
public static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
#Override
public void setAsText(String text){
setValue(sdf.parse(text));}
}