com.google.maps.internal.SafeEnumAdapter.java Source code

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Here is the source code for com.google.maps.internal.SafeEnumAdapter.java

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/*
 * Copyright 2014 Google Inc. 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 com.google.maps.internal;

import com.google.gson.TypeAdapter;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonToken;
import com.google.gson.stream.JsonWriter;

import java.io.IOException;
import java.util.Locale;
import java.util.logging.Logger;

/**
 * A {@link com.google.gson.TypeAdapter} that maps case-insensitive values to an enum type. If the
 * value is not found, an UNKNOWN value is returned, and logged. This allows the server to return
 * values this client doesn't yet know about.
 * @param <E> the enum type to map values to.
 */
public class SafeEnumAdapter<E extends Enum<E>> extends TypeAdapter<E> {

    private static Logger log = Logger.getLogger(SafeEnumAdapter.class.getName());

    private final Class<E> clazz;
    private final E unknownValue;

    /**
     * @param unknownValue the value to return if the value cannot be found.
     */
    public SafeEnumAdapter(E unknownValue) {
        if (unknownValue == null)
            throw new IllegalArgumentException();

        this.unknownValue = unknownValue;
        this.clazz = unknownValue.getDeclaringClass();
    }

    @Override
    public void write(JsonWriter out, E value) throws IOException {
        throw new UnsupportedOperationException("Unimplemented method");
    }

    @Override
    public E read(JsonReader reader) throws IOException {
        if (reader.peek() == JsonToken.NULL) {
            reader.nextNull();
            return null;
        }
        String value = reader.nextString();
        try {
            return Enum.valueOf(clazz, value.toUpperCase(Locale.ENGLISH));
        } catch (IllegalArgumentException iae) {
            log.warning(String.format("Unknown type for enum %s: '%s'", clazz.getName(), value));
            return unknownValue;
        }
    }
}