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There is a newer version: 1.4.20_1
/*
 * Copyright (C) 2005 Joe Walnes.
 * Copyright (C) 2006, 2007, 2008, 2009, 2011, 2015 XStream Committers.
 * All rights reserved.
 *
 * The software in this package is published under the terms of the BSD
 * style license a copy of which has been included with this distribution in
 * the LICENSE.txt file.
 *
 * Created on 20. March 2005 by Joe Walnes
 */
package com.thoughtworks.xstream.mapper;

import com.thoughtworks.xstream.converters.ConverterLookup;
import com.thoughtworks.xstream.converters.SingleValueConverter;
import com.thoughtworks.xstream.converters.enums.EnumSingleValueConverter;
import com.thoughtworks.xstream.core.Caching;

import java.util.EnumSet;
import java.util.HashMap;
import java.util.Map;


/**
 * Mapper that handles the special case of polymorphic enums in Java 1.5. This renames MyEnum$1 to MyEnum making it less
 * bloaty in the XML and avoiding the need for an alias per enum value to be specified. Additionally every enum is
 * treated automatically as immutable and non-refrenceable type that can be written as attribute.
 *
 * @author Joe Walnes
 * @author Jörg Schaible
 */
public class EnumMapper extends MapperWrapper implements Caching {

    private transient AttributeMapper attributeMapper;
    private transient Map enumConverterMap;

    /**
     * @deprecated As of 1.3.1, use {@link #EnumMapper(Mapper)}
     */
    @Deprecated
    public EnumMapper(Mapper wrapped, ConverterLookup lookup) {
        super(wrapped);
        readResolve();
    }

    public EnumMapper(Mapper wrapped) {
        super(wrapped);
        readResolve();
    }

    @Override
    public String serializedClass(Class type) {
        if (type == null) {
            return super.serializedClass(type);
        }
        if (Enum.class.isAssignableFrom(type) && type.getSuperclass() != Enum.class) {
            return super.serializedClass(type.getSuperclass());
        } else if (EnumSet.class.isAssignableFrom(type)) {
            return super.serializedClass(EnumSet.class);
        } else {
            return super.serializedClass(type);
        }
    }

    @Override
    public boolean isImmutableValueType(Class type) {
        return (Enum.class.isAssignableFrom(type)) || super.isImmutableValueType(type);
    }

    @Override
    public boolean isReferenceable(final Class type) {
        if (type != null && Enum.class.isAssignableFrom(type)) {
            return false;
        } else {
            return super.isReferenceable(type);
        }
    }

    @Override
    public SingleValueConverter getConverterFromItemType(String fieldName, Class type,
            Class definedIn) {
            SingleValueConverter converter = getLocalConverter(fieldName, type, definedIn);
            return converter == null
                ? super.getConverterFromItemType(fieldName, type, definedIn)
                : converter;
    }

    @Override
    public SingleValueConverter getConverterFromAttribute(Class definedIn, String attribute,
        Class type) {
        SingleValueConverter converter = getLocalConverter(attribute, type, definedIn);
        return converter == null
            ? super.getConverterFromAttribute(definedIn, attribute, type)
            : converter;
    }

    private SingleValueConverter getLocalConverter(String fieldName, Class type, Class definedIn) {
        if (attributeMapper != null
                && Enum.class.isAssignableFrom(type)
                && attributeMapper.shouldLookForSingleValueConverter(fieldName, type, definedIn)) {
            synchronized (enumConverterMap) {
                SingleValueConverter singleValueConverter = enumConverterMap.get(type);
                if (singleValueConverter == null) {
                    singleValueConverter = super.getConverterFromItemType(fieldName, type, definedIn);
                    if (singleValueConverter == null) {
                        @SuppressWarnings("unchecked")
                        Class enumType = type;
                        singleValueConverter = new EnumSingleValueConverter(enumType);
                    }
                    enumConverterMap.put(type, singleValueConverter);
                }
                return singleValueConverter;
            }
        }
        return null;
    }

    public void flushCache() {
        if (enumConverterMap.size() > 0) {
            synchronized (enumConverterMap) {
                enumConverterMap.clear();
            }
        }
    }

    private Object readResolve() {
        this.enumConverterMap = new HashMap();
        this.attributeMapper = (AttributeMapper)lookupMapperOfType(AttributeMapper.class);
        return this;
    }
}