nl.vpro.util.ProviderAndBuilder Maven / Gradle / Ivy
package nl.vpro.util;
import lombok.extern.slf4j.Slf4j;
import java.lang.reflect.*;
import java.time.Duration;
import java.util.Optional;
import jakarta.inject.Provider;
/**
* If you have a provider implementation based on a builder, you can fill the fields of the provider to the builder using
* reflection.
* Providers can come in usefull with IOC-frameworks like guice. The idea is to put {@link javax.inject.Named} annotation on the fields of the Provider.
*
* @author Michiel MeeuwissenLocaleParamConverter.java
* @since 1.69
*/
@Slf4j
public class ProviderAndBuilder {
public static S fill(Provider provider, S builder) throws InvocationTargetException, IllegalAccessException, ClassNotFoundException {
Class providerClass = provider.getClass();
Class builderClass = builder.getClass();
for (Field providerField : providerClass.getDeclaredFields()) {
providerField.setAccessible(true);
Class providerType = providerField.getType();
if (providerType.equals(builderClass)) {
continue;
}
Object providerValue = providerField.get(provider);
if (Optional.class.isAssignableFrom(providerType)) {
providerType = Class.forName(((ParameterizedType) providerField.getGenericType()).getActualTypeArguments()[0].getTypeName());
providerValue = providerValue == null ? null : ((Optional) providerValue).orElse(null);
}
Method builderMethod = getBuilderMethod(builderClass, providerField.getName(), providerType);
if (builderMethod != null) {
try {
builderMethod.invoke(builder, convert(providerValue, builderMethod.getParameterTypes()[0]));
} catch (IllegalArgumentException ia) {
throw new IllegalArgumentException(builderMethod + " (" + providerValue + "):" + ia.getMessage(), ia);
}
} else {
log.info("Ignored {}", providerField);
}
}
return builder;
}
protected static Object convert(Object o, Class dest) {
if (o == null) {
return null;
}
// I couldn't get DurationConvertor working for providers in magnolia. For now let the provider use String's. It doesn't really matter.
if (CharSequence.class.isInstance(o) && dest.isAssignableFrom(Duration.class)) {
try {
return TimeUtils.parseDuration((CharSequence) o).orElse(null);
} catch (RuntimeException rte) {
log.warn(rte.getMessage());
return null;
}
}
return o;
}
protected static Method getBuilderMethod(Class builderClass, String name, Class type) {
Method candidate = null;
for (Method method : builderClass.getMethods()) {
if (method.getName().equals(name)) {
if (method.getParameterCount() == 1) {
if (candidate == null) {
candidate = method;
} else {
if (method.getParameterTypes()[0].isAssignableFrom(type)) {
candidate = method;
}
}
}
}
}
return candidate;
}
public static S fillAndCatch(Provider provider, S builder) {
try {
return fill(provider, builder);
} catch (IllegalAccessException | InvocationTargetException | ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
}