org.jclouds.json.internal.ParseObjectFromElement.java Source code

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Here is the source code for org.jclouds.json.internal.ParseObjectFromElement.java

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/**
 *
 * Copyright (C) 2010 Cloud Conscious, LLC. <info@cloudconscious.com>
 *
 * ====================================================================
 * 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 org.jclouds.json.internal;

import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.gson.JsonElement;
import com.google.gson.JsonPrimitive;
import com.google.gson.MapTypeAdapter;

/**
 * This is a class that helps the default {@link MapTypeAdapter} make a sane object graph when the
 * value is set to {@code Object}
 * 
 * @author Adrian Cole
 */
public enum ParseObjectFromElement implements Function<JsonElement, Object> {
    SINGLETON;
    public Object apply(JsonElement input) {
        Object value = null;
        if (input == null || input.isJsonNull()) {
            value = null;
        } else if (input.isJsonPrimitive()) {
            JsonPrimitive primitive = input.getAsJsonPrimitive();
            if (primitive.isNumber()) {
                value = primitive.getAsNumber();
            } else if (primitive.isBoolean()) {
                value = primitive.getAsBoolean();
            } else {
                value = primitive.getAsString();
            }
        } else if (input.isJsonArray()) {
            value = Lists.newArrayList(Iterables.transform(input.getAsJsonArray(), this));
        } else if (input.isJsonObject()) {
            value = Maps.<String, Object>newLinkedHashMap(
                    Maps.transformValues(JsonObjectAsMap.INSTANCE.apply(input.getAsJsonObject()), this));
        }
        return value;
    }
}