package org.springframework.boot.convert;
import java.util.Collections;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.springframework.core.convert.converter.Converter;
import org.springframework.core.convert.converter.ConverterFactory;
import org.springframework.util.Assert;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
@SuppressWarnings("rawtypes")
abstract class LenientObjectToEnumConverterFactory<T> implements ConverterFactory<T, Enum<?>> {
private static Map<String, List<String>> ALIASES;
static {
MultiValueMap<String, String> aliases = new LinkedMultiValueMap<>();
aliases.add("true", "on");
aliases.add("false", "off");
ALIASES = Collections.unmodifiableMap(aliases);
}
@Override
@SuppressWarnings("unchecked")
public <E extends Enum<?>> Converter<T, E> getConverter(Class<E> targetType) {
Class<?> enumType = targetType;
while (enumType != null && !enumType.isEnum()) {
enumType = enumType.getSuperclass();
}
Assert.notNull(enumType, () -> "The target type " + targetType.getName() + " does not refer to an enum");
return new LenientToEnumConverter<>((Class<E>) enumType);
}
@SuppressWarnings("unchecked")
private class LenientToEnumConverter<E extends Enum> implements Converter<T, E> {
private final Class<E> enumType;
LenientToEnumConverter(Class<E> enumType) {
this.enumType = enumType;
}
@Override
public E convert(T source) {
String value = source.toString().trim();
if (value.isEmpty()) {
return null;
}
try {
return (E) Enum.valueOf(this.enumType, value);
}
catch (Exception ex) {
return findEnum(value);
}
}
private E findEnum(String value) {
String name = getCanonicalName(value);
List<String> aliases = ALIASES.getOrDefault(name, Collections.emptyList());
for (E candidate : (Set<E>) EnumSet.allOf(this.enumType)) {
String candidateName = getCanonicalName(candidate.name());
if (name.equals(candidateName) || aliases.contains(candidateName)) {
return candidate;
}
}
throw new IllegalArgumentException("No enum constant " + this.enumType.getCanonicalName() + "." + value);
}
private String getCanonicalName(String name) {
StringBuilder canonicalName = new StringBuilder(name.length());
name.chars().filter(Character::isLetterOrDigit).map(Character::toLowerCase)
.forEach((c) -> canonicalName.append((char) c));
return canonicalName.toString();
}
}
}