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/** @author  John Miller
 *  @version 1.0
 *  @date    Mon Jan 26 14:56:24 EST 2015
 *  @see     LICENSE (MIT style license file).
 */

import java.io.*;
import java.nio.file.Files;
import java.nio.file.Paths;
import static java.lang.System.out;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ObjectNode;

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/** The `ReadWrite` class provides methods for reading a Json stream into a Java Bean
 *  and writing a Java Bean into a Json stream.
 *  @see http://www.journaldev.com/2324/jackson-json-processing-api-in-java-example-tutorial
 */
public class ReadWriteJson
{
    private static ObjectMapper objectMapper = new ObjectMapper ();     // create ObjectMapper instance

    //::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    /** Read a file containing Json data into a Java Bean.
     *  @param fname  the name of Json file 
     */
    public static Employee read (String fname) throws IOException
    {
        byte [] jsonData = Files.readAllBytes (Paths.get (fname));
        return objectMapper.readValue (jsonData, Employee.class);       // convert Json string to object
    } // read

    //::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    /** Write a Java Bean into a stream (in this case a string).
     *  @param emp  the Employee Java Bean to write
     */
    public static StringWriter write (Employee emp) throws IOException
    {
        // configure Object mapper for pretty print
        objectMapper.configure (SerializationFeature.INDENT_OUTPUT, true);
         
        StringWriter stringEmp = new StringWriter ();                   // create string stream
        objectMapper.writeValue (stringEmp, emp);                       // write into string stream
        return stringEmp;
    } // write

    //::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    /** Run the program via the main method.
     *  @param args  the command-line arguments
     */
    public static void main (String [] args) throws IOException
    {
        out.println ("Read a Json stream/file into a Java Bean");
        Employee emp = read ("employee.txt");
        out.println ("Employee Object:\n" + emp);
         
        out.println ("Write a Java Bean into a Json stream");
        StringWriter stringEmp = write (emp);
        out.println ("Employee Json:\n" + stringEmp);
    } // main

} // ReadJson class