gov.whitehouse.utils.GsonUtils.java Source code

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Here is the source code for gov.whitehouse.utils.GsonUtils.java

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/*
 * This project constitutes a work of the United States Government and is
 * not subject to domestic copyright protection under 17 USC  105.
 * 
 * However, because the project utilizes code licensed from contributors
 * and other third parties, it therefore is licensed under the MIT
 * License.  http://opensource.org/licenses/mit-license.php.  Under that
 * license, permission is granted free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the conditions that any appropriate copyright notices and this
 * permission notice are included in all copies or substantial portions
 * of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/******************************************************************************
 *  Copyright (c) 2011 GitHub Inc.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  Contributors:
 *    Kevin Sawicki (GitHub Inc.) - initial API and implementation
 *****************************************************************************/
package gov.whitehouse.utils;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

import java.io.Reader;
import java.lang.reflect.Type;
import java.util.Date;

import static com.google.gson.FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES;

/**
 * Gson utilities.
 */
public abstract class GsonUtils {

    private static final Gson GSON = createGson(true);

    private static final Gson GSON_NO_NULLS = createGson(false);

    /**
     * Create the standard {@link Gson} configuration
     *
     * @return created gson, never null
     */
    public static final Gson createGson() {
        return createGson(true);
    }

    /**
     * Create the standard {@link Gson} configuration
     *
     * @param serializeNulls whether nulls should be serialized
     * @return created gson, never null
     */
    public static final Gson createGson(final boolean serializeNulls) {
        final GsonBuilder builder = new GsonBuilder();
        builder.registerTypeAdapter(Date.class, new DateFormatter());
        builder.setFieldNamingPolicy(LOWER_CASE_WITH_UNDERSCORES);
        if (serializeNulls) {
            builder.serializeNulls();
        }
        return builder.create();
    }

    /**
     * Get reusable pre-configured {@link Gson} instance
     *
     * @return Gson instance
     */
    public static final Gson getGson() {
        return GSON;
    }

    /**
     * Get reusable pre-configured {@link Gson} instance
     *
     * @return Gson instance
     */
    public static final Gson getGson(final boolean serializeNulls) {
        return serializeNulls ? GSON : GSON_NO_NULLS;
    }

    /**
     * Convert object to json
     *
     * @return json string
     */
    public static final String toJson(final Object object) {
        return toJson(object, true);
    }

    /**
     * Convert object to json
     *
     * @return json string
     */
    public static final String toJson(final Object object, final boolean includeNulls) {
        return includeNulls ? GSON.toJson(object) : GSON_NO_NULLS.toJson(object);
    }

    /**
     * Convert string to given type
     *
     * @return instance of type
     */
    public static final <V> V fromJson(String json, Class<V> type) {
        return GSON.fromJson(json, type);
    }

    /**
     * Convert string to given type
     *
     * @return instance of type
     */
    public static final <V> V fromJson(String json, Type type) {
        return GSON.fromJson(json, type);
    }

    /**
     * Convert content of reader to given type
     *
     * @return instance of type
     */
    public static final <V> V fromJson(Reader reader, Class<V> type) {
        return GSON.fromJson(reader, type);
    }

    /**
     * Convert content of reader to given type
     *
     * @return instance of type
     */
    public static final <V> V fromJson(Reader reader, Type type) {
        return GSON.fromJson(reader, type);
    }
}