com.balajeetm.mystique.core.module.GsonDeserialiser.java Source code

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Here is the source code for com.balajeetm.mystique.core.module.GsonDeserialiser.java

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/*
 * Copyright (c) Balajee TM 2016.
 * All rights reserved.
 * License -  @see <a href="http://www.apache.org/licenses/LICENSE-2.0"></a>
 */

/*
 * Created on 9 Oct, 2016 by balajeetm
 * http://www.balajeetm.com
 */
package com.balajeetm.mystique.core.module;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map.Entry;

import com.balajeetm.mystique.util.gson.convertor.GsonConvertor;
import com.balajeetm.mystique.util.json.convertor.JsonConvertor;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.NumericNode;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.databind.node.TextNode;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonNull;
import com.google.gson.JsonObject;
import com.google.gson.JsonPrimitive;

/**
 * The Class GsonDeserialiser.
 *
 * @author balajeetm
 * @param <T> the generic type
 */
public class GsonDeserialiser<T extends JsonElement> extends StdDeserializer<T> {

    /** The gson convertor. */
    JsonConvertor gsonConvertor;

    /** The Constant serialVersionUID. */
    private static final long serialVersionUID = 1L;

    /** Instantiates a new gson deserialiser. */
    public GsonDeserialiser() {
        this(JsonElement.class);
        gsonConvertor = GsonConvertor.getInstance();
    }

    /**
     * Instantiates a new gson deserialiser.
     *
     * @param vc the vc
     */
    public GsonDeserialiser(Class<?> vc) {
        super(vc);
    }

    /* (non-Javadoc)
     * @see com.fasterxml.jackson.databind.JsonDeserializer#deserialize(com.fasterxml.jackson.core.JsonParser, com.fasterxml.jackson.databind.DeserializationContext)
     */
    @Override
    public T deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        JsonNode node = p.getCodec().readTree(p);
        return deserialize(node);
    }

    /**
     * Deserialize.
     *
     * @param node the node
     * @return the json element
     */
    @SuppressWarnings("unchecked")
    private T deserialize(JsonNode node) {
        JsonElement result = JsonNull.INSTANCE;
        if (null != node && !node.isNull()) {
            if (node.isObject()) {
                ObjectNode onode = (ObjectNode) node;
                JsonObject jsonObject = new JsonObject();
                Iterator<Entry<String, JsonNode>> fields = onode.fields();
                while (fields.hasNext()) {
                    Entry<String, JsonNode> next = fields.next();
                    jsonObject.add(next.getKey(), deserialize(next.getValue()));
                }
                result = jsonObject;
            } else if (node.isArray()) {
                ArrayNode anode = (ArrayNode) node;
                JsonArray jsonArray = new JsonArray();
                Iterator<JsonNode> elements = anode.elements();
                while (elements.hasNext()) {
                    jsonArray.add(deserialize(elements.next()));
                }
                result = jsonArray;
            } else if (node.isBoolean()) {
                result = new JsonPrimitive(node.asBoolean());
            } else if (node.isNumber()) {
                NumericNode nnode = (NumericNode) node;
                result = new JsonPrimitive(nnode.numberValue());
            } else if (node.isTextual()) {
                TextNode tnode = (TextNode) node;
                result = new JsonPrimitive(tnode.textValue());
            }
        }

        return (T) result;
    }
}