com.smartgwt.client.util

Class JSON

java.lang.Object

com.smartgwt.client.util.JSON

public class JSON
extends java.lang.Object

Utilities for working with JSON data.

Constructor Summary

Constructors

Constructor and Description
JSON()

Method Summary

Modifier and Type	Method and Description
static com.google.gwt.core.client.JavaScriptObject	decode(java.lang.String jsonString) De-serialize an object from JSON.
static java.util.Map	decodeSafe(java.lang.String jsonString, Function jsonReviver) Decodes strict JSON using native browser JSON parsing APIs.
static void	decodeSafeWithDates(java.lang.String jsonString) Uses decodeSafe() to decode strict JSON using native browser JSON parsing APIs, with settings to correctly process formatted date values created with JSONDateFormat logicalDateConstructor.
static java.lang.String	encode(com.google.gwt.core.client.JavaScriptObject object) Serialize an object as a JSON string.
static java.lang.String	encode(com.google.gwt.core.client.JavaScriptObject object, JSONEncoder settings) Serialize an object as a JSON string.

Methods inherited from class java.lang.Object

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

Constructor Detail

JSON

public JSON()

Method Detail

decodeSafe

public static java.util.Map decodeSafe(java.lang.String jsonString,
                                       Function jsonReviver)

Decodes strict JSON using native browser JSON parsing APIs. This API will not work with pseudo-JSON that must be parsed as JavaScript (such as that produced by encoding with JSONDateFormat logicalDateConstructor).

This API is called "safe" because using a JavaScript eval() to decode JSON is potentially unsafe if the data being decoded is untrusted. For example, if users are able to save data as JSON for other uses to see (such as sharing ListGrid.viewState) and there is no validation of the saved data to ensure safety and some users are untrusted, then saved JSON could be used similarly to an XSS attack, allowing one user to execute JavaScript code in another user's browser.

Note that, because JSON has no way of representing dates, serializing a structure that contains dates and then deserializing with decodeSafe() necessarily results in any Dates becoming strings. Use JSONDateFormat "logicalDateString" in combination with decodeSafeWithDates() to round-trip date, time and datetime values accurately.

Parameters:

jsonString - JSON data to be de-serialized

jsonReviver - optional setting

Returns:

object derived from JSON String

decodeSafeWithDates

public static void decodeSafeWithDates(java.lang.String jsonString)

Uses decodeSafe() to decode strict JSON using native browser JSON parsing APIs, with settings to correctly process formatted date values created with JSONDateFormat logicalDateConstructor.

Parameters:

jsonString - JSON data to be de-serialized

encode

public static java.lang.String encode(com.google.gwt.core.client.JavaScriptObject object)

Serialize an object as a JSON string.

Automatically handles circular references - see circularReferenceMode.

Note that using the String produced by this API with JSON.decode will not successfully preserve dates. Use JSONEncoder.setDateFormat "dateConstructor" to have dates round-trip properly.

Because GWT does not support Java reflection, JSON encoding cannot discover the properties of an arbitrary Java POJO. The following objects are supported:

• any primitive type (String, Date, Number, Boolean)
• any Map or Collection in any level of nesting
• DataClass (Record's superclass) and RecordList
• any widget (see +link{JSONEncoder.serializeInstances})
• JavaScriptObject
• an Array containing any of the above

Parameters:

object - object to serialize

Returns:

object encoded as a JSON String

encode

public static java.lang.String encode(com.google.gwt.core.client.JavaScriptObject object,
                                      JSONEncoder settings)

Serialize an object as a JSON string.

Automatically handles circular references - see circularReferenceMode.

Note that using the String produced by this API with JSON.decode will not successfully preserve dates. Use JSONEncoder.setDateFormat "dateConstructor" to have dates round-trip properly.

Because GWT does not support Java reflection, JSON encoding cannot discover the properties of an arbitrary Java POJO. The following objects are supported:

• any primitive type (String, Date, Number, Boolean)
• any Map or Collection in any level of nesting
• DataClass (Record's superclass) and RecordList
• any widget (see +link{JSONEncoder.serializeInstances})
• JavaScriptObject
• an Array containing any of the above

Parameters:

object - object to serialize

settings - optional settings for encoding

Returns:

object encoded as a JSON String

decode

public static com.google.gwt.core.client.JavaScriptObject decode(java.lang.String jsonString)

De-serialize an object from JSON. Currently, this is simply a JavaScript eval() and should be used for trusted data only.

Parameters:

jsonString - JSON data to be de-serialized

Returns:

object derived from JSON String