determine whether ByteArrayOutputStream is of type JSONArray or JSONObject?

Question

ByteArrayOutputStream result = new ByteArrayOutputStream();
while ((length = inputStream.read(buffer)) != -1) {
        result.write(buffer, 0, length);
}

Is there a way to determine whether result contains a JSONObject or a JSONArray? I've been blindly casting it to a JSONObject however, i've hit a case where it is a JSONArray - any help would be appreciated.

JSON API: Using faster jackson and org.json

Thanks in advance

Answer 1

JSR 353 reference implementation

See https://jsonp.java.net/

These are the Maven dependencies:

<dependency>
    <groupId>javax.json</groupId>
    <artifactId>javax.json-api</artifactId>
    <version>1.0</version>
</dependency>

<dependency>
    <groupId>org.glassfish</groupId>
    <artifactId>javax.json</artifactId>
    <version>1.0.4</version>
    <scope>runtime</scope>
</dependency>

And the code sample:

// the JSON classes have package javax.json

ByteArrayOutputStream baos = new ByteArrayOutputStream();

// read JSON into baos

ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
InputStreamReader isr = new InputStreamReader(bais, Charset.forName("UTF-8"));
JsonReader jr = Json.createReader(isr);

JsonStructure js = jr.read();

switch (js.getValueType()) {
    case ARRAY:
        break;
    case OBJECT:
        break;
    case STRING:
        break;
    case NUMBER:
        break;
    case TRUE:
        break;
    case FALSE:
        break;
    case NULL:
        break;
}

FasterXML Jackson

(just a sample that works, most probably not the "best")

Maven dependency:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.6.3</version>
</dependency>

Code sample:

// see JsonNodeType
new ObjectMapper().reader().readTree("[]").getNodeType();