com.github.awsjavakit.eventbridge.handlers.EventParser Maven / Gradle / Ivy
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package com.github.awsjavakit.eventbridge.handlers;
import static com.github.awsjavakit.misc.exceptions.ExceptionUtils.stackTraceInSingleLine;
import static com.gtihub.awsjavakit.attempt.Try.attempt;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.awsjavakit.eventbridge.models.AwsEventBridgeEvent;
import com.gtihub.awsjavakit.attempt.Failure;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class EventParser {
public static final String ERROR_PARSING_INPUT = "Could not parse input: ";
public static final int SKIP_BOTTOM_TYPE = 2;
public static final String RAWTYPES = "rawtypes";
private static final Logger logger = LoggerFactory.getLogger(EventParser.class);
private final String input;
private final ObjectMapper objectMapper;
public EventParser(String input, ObjectMapper objectMapper) {
this.input = input;
this.objectMapper = objectMapper;
}
public AwsEventBridgeEvent parse(Class iclass) {
return attempt(() -> parseJson(iclass)).orElseThrow(this::handleParsingError);
}
/**
* Given the nested parameter classes ClassA,ClassB,ClassC,...,ClassZ, this method returns the an
* AwsEventBridgeEvent where the detail object in of type
* {@literal ClassA>..>}.
*
* @param nestedParameterClasses the classes of the nested generic type of the detail object.
* @return an AwsEventBridgeEvent with a nested generic type as detail object.
*/
/*
Using raw types because of Java's type erasure for nested generic classes.
I.e. one cannot retrieve the java.lang.Class instance for the type ClassA.
*/
@SuppressWarnings(RAWTYPES)
public AwsEventBridgeEvent parse(Class... nestedParameterClasses) {
return attempt(() -> parseJson(nestedParameterClasses)).orElseThrow(this::handleParsingError);
}
private AwsEventBridgeEvent parseJson(Class iclass) throws JsonProcessingException {
JavaType javaType =
objectMapper.getTypeFactory().constructParametricType(AwsEventBridgeEvent.class, iclass);
return objectMapper.readValue(input, javaType);
}
private AwsEventBridgeEvent parseJson(Class... nestedClasses)
throws JsonProcessingException {
JavaType nestedJavaTypes = nestedGenericTypesToJavaType(nestedClasses);
JavaType eventBridgeJavaType = constructAwsEventBridgeDataTypeWithAllNestedTypes(
nestedJavaTypes);
return objectMapper.readValue(input, eventBridgeJavaType);
}
private RuntimeException handleParsingError(Failure fail) {
logger.error(ERROR_PARSING_INPUT + input);
logger.error(stackTraceInSingleLine(fail.getException()));
return new RuntimeException(fail.getException());
}
/*
* Given an array of {@link Class} generic classes ClassA,ClassB,ClassC,...ClassZ,
* it creates a {@link JavaType} for the object ClassA>>>
*/
@SuppressWarnings(RAWTYPES)
private JavaType nestedGenericTypesToJavaType(Class... classes) {
//Variables not inlined for readability purposes.
JavaType mostRecentType = objectMapper.getTypeFactory().constructType(innermostType(classes));
for (int index = classes.length - SKIP_BOTTOM_TYPE; index >= 0; index--) {
Class currentClass = classes[index];
mostRecentType = createGenericClassContainingAllPreviousTypes(mostRecentType, currentClass);
}
return mostRecentType;
}
private JavaType createGenericClassContainingAllPreviousTypes(JavaType mostRecentType,
Class currentClass) {
return objectMapper.getTypeFactory().constructParametricType(currentClass, mostRecentType);
}
@SafeVarargs
private T innermostType(T... classes) {
return classes[classes.length - 1];
}
private JavaType constructAwsEventBridgeDataTypeWithAllNestedTypes(JavaType mostRecentType) {
return objectMapper.getTypeFactory()
.constructParametricType(AwsEventBridgeEvent.class, mostRecentType);
}
}