Package org.eclipse.jetty.util.ajax

Class AsyncJSON

java.lang.Object

org.eclipse.jetty.util.ajax.AsyncJSON

public class AsyncJSON
extends Object

A non-blocking JSON parser that can parse partial JSON strings.

Usage:

 AsyncJSON parser = new AsyncJSON.Factory().newAsyncJSON();

 // Feed the parser with partial JSON string content.
 parser.parse(chunk1);
 parser.parse(chunk2);

 // Tell the parser that the JSON string content
 // is terminated and get the JSON object back.
 Map<String, Object> object = parser.complete();
 

After the call to complete() the parser can be reused to parse another JSON string.

Custom objects can be created by specifying a "class" or "x-class" field:

 String json = """
 {
   "x-class": "com.acme.Person",
   "firstName": "John",
   "lastName": "Doe",
   "age": 42
 }
 """

 parser.parse(json);
 com.acme.Person person = parser.complete();
 

Class com.acme.Person must either implement JSON.Convertible, or be mapped with a JSON.Convertor via AsyncJSON.Factory.putConvertor(String, Convertor).

JSON arrays are by default represented with a List<Object>, but the Java representation can be customized via AsyncJSON.Factory.setArrayConverter(Function).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	AsyncJSON.Context	The state of JSON parsing.
static class	AsyncJSON.Factory	The factory that creates AsyncJSON instances.

Constructor Summary

Constructors

Constructor	Description
AsyncJSON(AsyncJSON.Factory factory)

Method Summary

Modifier and Type	Method	Description
<R> R	complete()	Signals to the parser that the parse data is complete, and returns the object parsed from the JSON chunks passed to the parse() methods.
protected List<Object>	newArray(AsyncJSON.Context context)	When a JSON [ is encountered during parsing, this method is called to create a new List instance.
protected RuntimeException	newInvalidJSON(ByteBuffer buffer, String message)
protected Map<String,Object>	newObject(AsyncJSON.Context context)	When a JSON { is encountered during parsing, this method is called to create a new Map instance.
boolean	parse(byte[] bytes)	Feeds the parser with the given bytes chunk.
boolean	parse(byte[] bytes, int offset, int length)	Feeds the parser with the given bytes chunk.
boolean	parse(ByteBuffer buffer)	Feeds the parser with the given buffer chunk.

Methods inherited from class java.lang.Object

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

Constructor Details

AsyncJSON

public AsyncJSON(AsyncJSON.Factory factory)

Method Details

parse

public boolean parse(byte[] bytes)

Feeds the parser with the given bytes chunk.

Parameters:

bytes - the bytes to parse

Returns:

whether the JSON parsing was complete

Throws:

IllegalArgumentException - if the JSON is malformed

parse

public boolean parse(byte[] bytes,
 int offset,
 int length)

Feeds the parser with the given bytes chunk.

Parameters:

bytes - the bytes to parse

offset - the offset to start parsing from

length - the number of bytes to parse

Returns:

whether the JSON parsing was complete

Throws:

IllegalArgumentException - if the JSON is malformed

parse

public boolean parse(ByteBuffer buffer)

Feeds the parser with the given buffer chunk.

Parameters:

buffer - the buffer to parse

Returns:

whether the JSON parsing was complete

Throws:

IllegalArgumentException - if the JSON is malformed

complete

public <R> R complete()

Signals to the parser that the parse data is complete, and returns the object parsed from the JSON chunks passed to the parse() methods.

Type Parameters:

R - the type the result is cast to

Returns:

the result of the JSON parsing

Throws:

IllegalArgumentException - if the JSON is malformed

IllegalStateException - if the no JSON was passed to the parse() methods

newObject

protected Map<String,Object> newObject(AsyncJSON.Context context)

When a JSON { is encountered during parsing, this method is called to create a new Map instance.

Subclasses may override to return a custom Map instance.

Parameters:

context - the parsing context

Returns:

a Map instance

newArray

protected List<Object> newArray(AsyncJSON.Context context)

When a JSON [ is encountered during parsing, this method is called to create a new List instance.

Subclasses may override to return a custom List instance.

Parameters:

context - the parsing context

Returns:

a List instance

newInvalidJSON

protected RuntimeException newInvalidJSON(ByteBuffer buffer,
 String message)