org.json.JSONStringer Maven / Gradle / Ivy

package org.json;

/*
Public Domain.
*/

import java.io.StringWriter;

/**
 * JSONStringer provides a quick and convenient way of producing JSON text.
 * The texts produced strictly conform to JSON syntax rules. No whitespace is
 * added, so the results are ready for transmission or storage. Each instance of
 * JSONStringer can produce one JSON text.
 * 
 * A JSONStringer instance provides a value method for appending
 * values to the
 * text, and a key
 * method for adding keys before values in objects. There are array
 * and endArray methods that make and bound array values, and
 * object and endObject methods which make and bound
 * object values. All of these methods return the JSONWriter instance,
 * permitting cascade style. For example, 
 * myString = new JSONStringer()
 *     .object()
 *         .key("JSON")
 *         .value("Hello, World!")
 *     .endObject()
 *     .toString();
 which produces the string  * {"JSON":"Hello, World!"}
 * 
 * The first method called must be array or object.
 * There are no methods for adding commas or colons. JSONStringer adds them for
 * you. Objects and arrays can be nested up to 200 levels deep.
 * 
 * This can sometimes be easier than using a JSONObject to build a string.
 * @author JSON.org
 * @version 2015-12-09
 */
public class JSONStringer extends JSONWriter {
    /**
     * Make a fresh JSONStringer. It can be used to build one JSON text.
     */
    public JSONStringer() {
        super(new StringWriter());
    }

    /**
     * Return the JSON text. This method is used to obtain the product of the
     * JSONStringer instance. It will return null if there was a
     * problem in the construction of the JSON text (such as the calls to
     * array were not properly balanced with calls to
     * endArray).
     * @return The JSON text.
     */
    @Override
    public String toString() {
        return this.mode == 'd' ? this.writer.toString() : null;
    }
}