modules/types/src/main/java/org/apache/tamaya/types/internal/converters/EnumConverter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *   http://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.apache.tamaya.types.internal.converters;

import org.apache.tamaya.ConfigException;
import org.apache.tamaya.types.spi.ConversionContext;
import org.apache.tamaya.types.spi.PropertyConverter;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Locale;
import java.util.Objects;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Converter, converting from String to tge given enum type.
 */
public class EnumConverter<T> implements PropertyConverter<T> {
    private final Logger LOG = Logger.getLogger(EnumConverter.class.getName());
    private Class<T> enumType;
    private Method factory;

    public EnumConverter(Class<T> enumType) {
        if (!Enum.class.isAssignableFrom(enumType)) {
            throw new IllegalArgumentException("Not an Enum: " + enumType.getName());
        }
        this.enumType = Objects.requireNonNull(enumType);
        try {
            this.factory = enumType.getMethod("valueOf", String.class);
        } catch (NoSuchMethodException e) {
            throw new ConfigException("Uncovertible enum type without valueOf method found, please provide a custom " +
                    "PropertyConverter for: " + enumType.getName());
        }
    }

    @Override
    public T convert(String value, ConversionContext context) {
        context.addSupportedFormats(getClass(),"<enumValue>");
        try {
            return (T) factory.invoke(null, value);
        } catch (InvocationTargetException | IllegalAccessException e) {
            LOG.log(Level.FINEST, "Invalid enum value '" + value + "' for " + enumType.getName(), e);
        }
        try {
            return (T) factory.invoke(null, value.toUpperCase(Locale.ENGLISH));
        } catch (InvocationTargetException | IllegalAccessException e) {
            LOG.log(Level.FINEST, "Invalid enum value '" + value + "' for " + enumType.getName(), e);
        }
        return null;
    }
}