ej.json

Class JSONWriter

java.lang.Object

ej.json.JSONWriter

public class JSONWriter
extends Object

JSONWriter 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 JSONWriter can produce one JSON text.

A JSONWriter 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 a cascade style. For example,

 new JSONWriter(myOutputStream)
     .object()
         .key("JSON")
         .value("Hello, World!")
     .endObject();

which writes

 {"JSON":"Hello, World!"}

The first method called must be array or object. There are no methods for adding commas or colons. JSONWriter adds them for you. Objects and arrays can be nested up to 20 levels deep.

Version:

2

Author:

JSON.org

Field Summary

Fields

Modifier and Type	Field and Description
protected char	mode The current mode.
protected OutputStream	os The stream that will receive the output.

Constructor Summary

Constructors

Constructor and Description
JSONWriter(OutputStream os) Make a fresh JSONWriter.

Method Summary

Modifier and Type	Method and Description
JSONWriter	array() Begin appending a new array.
JSONWriter	endArray() End an array.
JSONWriter	endObject() End an object.
JSONWriter	key(String s) Append a key.
JSONWriter	object() Begin appending a new object.
static String	quote(String string) Produce a string in double quotes with backslash sequences in all the right places.
JSONWriter	value(boolean b) Append either the value true or the value false.
JSONWriter	value(double d) Append a double value.
JSONWriter	value(long l) Append a long value.
JSONWriter	value(String s) Append a String value.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

mode

protected char mode

The current mode. Values: 'a' (array), 'd' (done), 'i' (initial), 'k' (key), 'o' (object).

os

protected OutputStream os

The stream that will receive the output.

Constructor Detail

JSONWriter

public JSONWriter(OutputStream os)

Make a fresh JSONWriter. It can be used to build one JSON text.

Parameters:

w - the output stream

Method Detail

array

public JSONWriter array()
                 throws JSONException

Begin appending a new array. All values until the balancing endArray will be appended to this array. The endArray method must be called to mark the array's end.

Returns:

this

Throws:

JSONException - If the nesting is too deep, or if the object is started in the wrong place (for example as a key or after the end of the outermost array or object).

endArray

public JSONWriter endArray()
                    throws JSONException

End an array. This method most be called to balance calls to array.

Returns:

this

Throws:

JSONException - If incorrectly nested.

endObject

public JSONWriter endObject()
                     throws JSONException

End an object. This method most be called to balance calls to object.

Returns:

this

Throws:

JSONException - If incorrectly nested.

key

public JSONWriter key(String s)
               throws JSONException

Append a key. The key will be associated with the next value. In an object, every value must be preceded by a key.

Parameters:

s - A key string.

Returns:

this

Throws:

JSONException - If the key is out of place. For example, keys do not belong in arrays or if the key is null.

object

public JSONWriter object()
                  throws JSONException

Begin appending a new object. All keys and values until the balancing endObject will be appended to this object. The endObject method must be called to mark the object's end.

Returns:

this

Throws:

JSONException - If the nesting is too deep, or if the object is started in the wrong place (for example as a key or after the end of the outermost array or object).

quote

public static String quote(String string)

Produce a string in double quotes with backslash sequences in all the right places. A backslash will be inserted within </, allowing JSON text to be delivered in HTML. In JSON text, a string cannot contain a control character or an unescaped quote or backslash.

Parameters:

string - A String

Returns:

A String correctly formatted for insertion in a JSON text.

value

public JSONWriter value(boolean b)
                 throws JSONException

Append either the value true or the value false.

Parameters:

b - A boolean.

Returns:

this

Throws:

JSONException

value

public JSONWriter value(double d)
                 throws JSONException

Append a double value.

Parameters:

d - A double.

Returns:

this

Throws:

JSONException - If the number is not finite.

value

public JSONWriter value(long l)
                 throws JSONException

Append a long value.

Parameters:

l - A long.

Returns:

this

Throws:

JSONException

value

public JSONWriter value(String s)
                 throws JSONException

Append a String value.

Parameters:

s - A String

Returns:

this

Throws:

JSONException