org.codehaus.groovy.grails.web.json
Class JSONWriter

java.lang.Object
  org.codehaus.groovy.grails.web.json.JSONWriter

Direct Known Subclasses:

PathCapturingJSONWriterWrapper, PrettyPrintJSONWriter

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(myWriter)
     .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.

This can sometimes be easier than using a JSONObject to build a string.

Version:

2

Author:

JSON.org

Nested Class Summary

protected static class

JSONWriter.Mode Enumeration of the possible modes of the JSONWriter

Field Summary

protected boolean	comma The comma flag determines if a comma should be output before the next value.
protected JSONWriter.Mode	mode The current mode.
protected Writer	writer The writer that will receive the output.

Constructor Summary

JSONWriter(Writer w)
Make a fresh JSONWriter.

Method Summary

protected JSONWriter	append(String s) Append a value.
JSONWriter	array() Begin appending a new array.
protected void	comma()
protected JSONWriter	end(JSONWriter.Mode m, char c) End something.
JSONWriter	endArray() End an array.
JSONWriter	endObject() End an object.
JSONWriter	key(String s) Append a key.
JSONWriter	object() Begin appending a new object.
protected void	pop(JSONWriter.Mode c) Pop an array or object scope.
protected void	push(JSONWriter.Mode c) Push an array or object scope.
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(Object o) Append an object value.

Methods inherited from class java.lang.Object

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

Field Detail

comma

protected boolean comma

The comma flag determines if a comma should be output before the next value.

mode

protected JSONWriter.Mode mode

The current mode. Values:

writer

protected Writer writer

The writer that will receive the output.

Constructor Detail

JSONWriter

public JSONWriter(Writer w)

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

Method Detail

append

protected JSONWriter append(String s)

Append a value.

Parameters:

s - A string value.

Returns:

this

comma

protected void comma()

array

public JSONWriter array()

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

end

protected JSONWriter end(JSONWriter.Mode m,
                         char c)

End something.

Parameters:

m - Mode

c - Closing character

Returns:

this

endArray

public JSONWriter endArray()

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

Returns:

this

endObject

public JSONWriter endObject()

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

Returns:

this

key

public JSONWriter key(String s)

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

object

public JSONWriter object()

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

pop

protected void pop(JSONWriter.Mode c)

Pop an array or object scope.

Parameters:

c - The scope to close.

push

protected void push(JSONWriter.Mode c)

Push an array or object scope.

Parameters:

c - The scope to open.

value

public JSONWriter value(boolean b)

Append either the value true or the value false.

Parameters:

b - A boolean.

Returns:

this

value

public JSONWriter value(double d)

Append a double value.

Parameters:

d - A double.

Returns:

this

value

public JSONWriter value(long l)

Append a long value.

Parameters:

l - A long.

Returns:

this

value

public JSONWriter value(Object o)

Append an object value.

Parameters:

o - The object to append. It can be null, or a Boolean, Number, String, JSONObject, or JSONArray.

Returns:

this