This is the Itemscript JSON Toolkit for standard Java and GWT Java.

Main components:

1. A cross-platform GWT & standard Java JSON library, with convenient classes, parsers, and utilities.
2. A RESTful connector API for retrieval of data (JSON, text & small binary files) over a variety of protocols.
3. A simple in-memory database with a RESTful interface, useful as a mock server for testing & development, and for managing application state.
4. A validator for the Itemscript Schema JSON schema language.
5. The JAM template language, using JSON values, usable in both GWT & standard Java.

Please feel free to log any issues, or contact us directly with questions or comments.

News

• 1.0.0 release - July 29th, 2010 - Added schema and template modules, numerous bug fixes, some minor incompatible interface changes with previous versions.
• 0.9.11 release - March 26th, 2010 - Content-type bug-fixes for HTTP connectors; added HTML pretty-printing of JSON values to StaticJsonUtil; pagedKeys and pagedItems queries to mem: URLs now support orderBy and ascending parameters for sorting results by field or in reverse order; adding an event handler now returns a HandlerReg that can be used to remove the Handler later.

1. JSON library features

• The same JSON API can be used in both standard Java and in GWT Java.
• In standard Java the JSON parser is derived from the org.json.simple parser by FangYidong.
• In GWT Java the browser-native JSON.parse() is used where available, or eval() if not.
• JsonObject implements Map<String,JsonValue>.
• JsonArray implements List<JsonValue>.
• Typed get and put methods for containers that convert to & from Java types - e.g. getString(String key), put(String key, Long value).
• Get methods for containers that throw exceptions when values are missing or of the wrong type - e.g. getRequiredString().
• Check methods for containers that test for existence and type - e.g. hasString()
• Stores Java longs safely in JsonString values.
• Incorporates transparent/lazy base64 encoding & decoding for storing binary values in JsonString values.
• Chainable put & add methods for containers, allowing for inline initialization - p(key, value) for objects, a(value) for arrays.
• Convenience methods for creating an object or array inside another object or array.
• Event handlers allow for actions to be taken when a value changes.
• Enforced consistency relationships: a value may only be in one container; cycles in parent relationships (X->Y->X) are not permitted.

2. RESTful data retrieval API

This provides a simple, extensible RESTful interface to data storage. The API consists of Map-style get/put/delete operations that accept URLs as keys; they allow you to treat the web as a hashtable with URLs for keys. For GWT, asynchronous versions of these operations that accept callbacks are provided for retrieval via HTTP or JSONP.

In GWT Java there are connectors for:

• http: for same-domain REST operations.
• jsonp: for cross-domain requests.
• file: URLs for testing locally.
• cookie: for simple access to cookies.
• mem: for in-memory storage & server mock-ups.

In standard Java there are connectors for:

• http: & file: URLs.
• mem: for in-memory storage.
• classpath: for loading bundled resources.

This API is easily extensible using the pluggable connector interface.

3. In-memory RESTful database

This simple database provides storage and retrieval of resources via HTTP-style hierarchical URLs. It is intended primarily for mocking-up & testing of REST applications without needing to configure a server, and so it imitates the operations a typical REST server might provide.

It can also be used as a configuration database, a cache, or to mediate interactions between various sub-systems in an application; sub-systems may attach event handlers to resources and be notified when they change, allowing decoupling of interactions. It can be used in both browser and standard Java environments.

Getting started guide to the in-memory database

4. Itemscript Schema validator

The toolkit includes a validator for the Itemscript Schema language, allowing you to validate JSON values against types defined using that language, usable for both immediate client-side validation and server-side validation.

5. JAM template language

The JAM template language allows you to use JSON values to interpret templates; templates can produce text or JSON values as output. The template language can be efficiently parsed and compiled even in browser environments.

Examples

Examples of many of these features can be found here; a worked example of the Foundry/Factory system can be found here.

Getting started

Getting started guide for standard Java

Getting started guide for GWT Java

Getting started with the in-memory database

Other projects

The JAM (JSON Application Markup) language describes applications, interfaces, events and data in a simple language based on JSON name:value pairs. JAM extends the Itemscript specification.

The Web Data Model is a description of the implicit data model of the RESTful web; the in-memory database in Itemscript tries to emulate a simple, standard set of operations on it.

Some notes on making a Java library that can be used both in standard Java environments and GWT.

Read the FAQ for more information.

http://itemscript.org/.

Itemscript is a registered trademark of Database Architects, Inc. Itemscript is an open source work published under the new BSD license.