org.springframework.boot.convert.LenientObjectToEnumConverterFactory Maven / Gradle / Ivy
/*
* Copyright 2012-2019 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
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;
/**
* Abstract base class for converting from a type to a {@link java.lang.Enum}.
*
* @param the source type
* @author Phillip Webb
* @author Madhura Bhave
*/
@SuppressWarnings("rawtypes")
abstract class LenientObjectToEnumConverterFactory implements ConverterFactory> {
private static Map> ALIASES;
static {
MultiValueMap aliases = new LinkedMultiValueMap<>();
aliases.add("true", "on");
aliases.add("false", "off");
ALIASES = Collections.unmodifiableMap(aliases);
}
@Override
@SuppressWarnings("unchecked")
public > Converter getConverter(Class 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) enumType);
}
@SuppressWarnings("unchecked")
private class LenientToEnumConverter implements Converter {
private final Class enumType;
LenientToEnumConverter(Class 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 aliases = ALIASES.getOrDefault(name, Collections.emptyList());
for (E candidate : (Set) 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();
}
}
}