com.ibm.common.activitystreams.internal.EnumAdapter.java Source code

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Here is the source code for com.ibm.common.activitystreams.internal.EnumAdapter.java

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/**
 * Copyright 2013 OpenSocial Foundation
 * Copyright 2013 International Business Machines Corporation
 *
 * 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.
 *
 * Utility library for working with Activity Streams Actions
 * Requires underscorejs.
 *
 * @author James M Snell (jasnell@us.ibm.com)
 */
package com.ibm.common.activitystreams.internal;

import static com.google.common.base.Enums.stringConverter;
import static com.google.common.base.Preconditions.checkArgument;
import static com.ibm.common.activitystreams.util.Converters.stringConverter;
import static com.ibm.common.activitystreams.util.Converters.toLowerConverter;
import static com.ibm.common.activitystreams.util.Converters.toUpperConverter;

import java.lang.reflect.Type;

import com.google.common.base.Converter;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;

/**
 * @author james
 * @version $Revision: 1.0 $
 */
public final class EnumAdapter<E extends Enum<E>> extends Adapter<E> {

    protected static final Converter<String, String> toLower = toLowerConverter();
    protected static final Converter<String, String> toUpper = toUpperConverter();

    private final Converter<String, E> des;
    private final Converter<E, String> ser;

    /**
     * Constructor for EnumAdapter.
     * @param _enumClass Class<E>
     */
    public EnumAdapter(Class<E> _enumClass) {
        this(_enumClass, stringConverter(_enumClass));
    }

    /**
     * Constructor for EnumAdapter
        
        
     * @param _enumClass Class<E>
     * @param or E
     */
    public EnumAdapter(Class<E> _enumClass, E or) {
        this(_enumClass, stringConverter(_enumClass, or));
    }

    /**
     * Constructor for EnumAdapter.
     * @param _enumClass Class<E>
        
     * @param c Converter<String,E>
     */
    public EnumAdapter(Class<E> _enumClass, Converter<String, E> c) {
        super();
        this.des = toUpper.andThen(c);
        this.ser = c.reverse().andThen(toLower);
    }

    /**
     * Method serialize.
     * @param src E
     * @param typeOfSrc Type
     * @param context JsonSerializationContext
     * @return JsonElement
     */
    public JsonElement serialize(E src, Type typeOfSrc, JsonSerializationContext context) {
        return context.serialize(ser.convert(src));
    }

    /**
     * Method deserialize.
     * @param json JsonElement
     * @param typeOfT Type
     * @param context JsonDeserializationContext
     * @return E
     * @throws JsonParseException
     * @see com.google.gson.JsonDeserializer#deserialize(JsonElement, Type, JsonDeserializationContext)
     */
    public E deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        checkArgument(json.isJsonPrimitive());
        JsonPrimitive jp = json.getAsJsonPrimitive();
        checkArgument(jp.isString());
        return des.convert(jp.getAsString());
    }

    /**
     * Method convert.
     * @param s String
     * @return E
     */
    protected E convert(String s) {
        return des.convert(s);
    }

}