google.registry.util.XmlToEnumMapper.java Source code

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Here is the source code for google.registry.util.XmlToEnumMapper.java

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// Copyright 2016 The Nomulus Authors. All Rights Reserved.
//
// 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
//
//     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 google.registry.util;

import static google.registry.util.PreconditionsUtils.checkArgumentNotNull;

import com.google.common.collect.ImmutableMap;
import javax.xml.bind.annotation.XmlEnumValue;

/** Efficient lookup from xml enums to java enums */
public final class XmlToEnumMapper<T extends Enum<?>> {

    private final ImmutableMap<String, T> map;

    /** Look up T from the {@link XmlEnumValue} */
    public T xmlToEnum(String value) {
        return map.get(value);
    }

    /**
     * Creates a new {@link XmlToEnumMapper} from xml value to enum value.
     */
    public static <T extends Enum<?>> XmlToEnumMapper<T> create(T[] enumValues) {
        return new XmlToEnumMapper<T>(enumValues);
    }

    private XmlToEnumMapper(T[] enumValues) {
        ImmutableMap.Builder<String, T> mapBuilder = new ImmutableMap.Builder<>();
        for (T value : enumValues) {
            try {
                XmlEnumValue xmlAnnotation = value.getDeclaringClass().getField(value.name())
                        .getAnnotation(XmlEnumValue.class);
                checkArgumentNotNull(xmlAnnotation, "Cannot map enum value to xml name: " + value);
                String xmlName = xmlAnnotation.value();
                mapBuilder = mapBuilder.put(xmlName, value);
            } catch (NoSuchFieldException e) {
                throw new RuntimeException(e);
            }
        }
        map = mapBuilder.build();
    }
}