JarCastingOverview
exificient-for-json is an implementation of the EXI4JSON specification (see https://www.w3.org/TR/exi-for-json/) in Java. EXI4JSON converts JSON to event streams which result in a very processing efficient and compact format. Lossless round-trip conversion back to the original JSON structures is supported. EXI4JSON is based on EXI and uses its built-in datatypes.
The project uses MIT license.
Background
Due to its EXI/XML nature EXI4JSON can be serialized/visualized as XML. Most of the use-case do not need this features but in some situation it may turn out very hand.
A JSON example
{
"keyNumber": 123,
"keyArrayStrings": [
"s1",
"s2"
]
}
can be transformed to
<j:map xmlns:j="http://www.w3.org/2015/EXI/json">
<j:keyNumber>
<j:number>123</j:number>
</j:keyNumber>
<j:keyArrayStrings>
<j:array>
<j:string>s1</j:string>
<j:string>s2</j:string>
</j:array>
</j:keyArrayStrings>
</j:map>
How to get it
Released with Maven
<dependency>
<groupId>com.siemens.ct.exi</groupId>
<artifactId>exificient-for-json</artifactId>
<version>1.0.0</version>
</dependency>
or also as snapshot.
<dependency>
<groupId>com.siemens.ct.exi</groupId>
<artifactId>exificient-for-json</artifactId>
<version>1.0.1-SNAPSHOT</version>
</dependency>
How to use the library
Java API for JSON Processing
// generate by simply providing input and output
EXIforJSONGenerator e4jGenerator = new EXIforJSONGenerator();
e4jGenerator.generate(isJSON, osEXI4JSON);
// Note: one can also fire events like writeStartObject(), writeKeyName(key) etc
// parse by simply providing input and output again
EXIforJSONParser e4jParser = new EXIforJSONParser();
e4jParser.parse(isEXI4JSON, osJSON);
// Note: one can again read events by readNextEvent(), getKeyName(), getValueString() etc
Jackson
EXI4JSONFactory fEXI = new EXI4JSONFactory();
ObjectMapper mapperEXI = new ObjectMapper(fEXI);
ObjectMapper mapperJSON = new ObjectMapper();
String carJson =
"{ \"brand\" : \"Mercedes\", \"doors\" : 5 }";
JsonNode car = mapperJSON.readTree(carJson);
// generate
OutputStream e4jOS = ...; // output stream
mapperEXI.writeTree(fEXI.createGenerator(e4jOS), car);
// parse
OutputStream e4jIS = ...; // input stream
EXI4JSONParser eparser = fEXI.createParser(e4jIS);
JsonNode carAgain = mapperJSON.readTree(eparser);
Compression Results
See test-data in https://github.com/EXIficient/exificient-for-json/tree/master/src/test/resources.
| TestCase | JSON [Size in Bytes] | CBOR [Size in Bytes] | Smile [Size in Bytes] | EXI4JSON [Size in Bytes] |
|---|---|---|---|---|
| glossary.json | 605 | 311 | 309 | 322 |
| gpx\sample-set-1\gpx-1-100pts.json | 11007 | 7378 | 6592 | 6210 |
| gpx\sample-set-1\gpx-1-10pts.json | 1318 | 898 | 832 | 778 |
| gpx\sample-set-1\gpx-1-1pts.json | 314 | 248 | 254 | 223 |
| gpx\sample-set-1\gpx-1-200pts.json | 21661 | 14578 | 12992 | 12179 |
| gpx\sample-set-1\gpx-1-20pts.json | 2424 | 1618 | 1472 | 1395 |
| gpx\sample-set-1\gpx-1-2pts.json | 426 | 322 | 320 | 284 |
| gpx\sample-set-1\gpx-1-300pts.json | 32452 | 21778 | 19392 | 18216 |
| gpx\sample-set-1\gpx-1-30pts.json | 3480 | 2338 | 2112 | 1984 |
| gpx\sample-set-1\gpx-1-3pts.json | 537 | 394 | 384 | 346 |
| gpx\sample-set-1\gpx-1-400pts.json | 43257 | 28978 | 25792 | 24239 |
| gpx\sample-set-1\gpx-1-40pts.json | 4562 | 3058 | 2752 | 2588 |
| gpx\sample-set-1\gpx-1-4pts.json | 648 | 466 | 448 | 408 |
| gpx\sample-set-1\gpx-1-500pts.json | 53988 | 36178 | 32192 | 30256 |
| gpx\sample-set-1\gpx-1-50pts.json | 5634 | 3778 | 3392 | 3191 |
| gpx\sample-set-1\gpx-1-5pts.json | 760 | 538 | 512 | 469 |
| gpx\sample-set-1\gpx-1-600pts.json | 64758 | 43378 | 38592 | 36284 |
| gpx\sample-set-1\gpx-1-60pts.json | 6720 | 4498 | 4032 | 3801 |
| gpx\sample-set-1\gpx-1-6pts.json | 872 | 610 | 576 | 531 |
| gpx\sample-set-1\gpx-1-700pts.json | 75518 | 50578 | 44992 | 42285 |
| gpx\sample-set-1\gpx-1-70pts.json | 7778 | 5218 | 4672 | 4396 |
| gpx\sample-set-1\gpx-1-7pts.json | 983 | 682 | 640 | 593 |
| gpx\sample-set-1\gpx-1-800pts.json | 86292 | 57778 | 51392 | 48293 |
| gpx\sample-set-1\gpx-1-80pts.json | 8859 | 5938 | 5312 | 5000 |
| gpx\sample-set-1\gpx-1-870pts.json | 93786 | 62818 | 55872 | 52476 |
| gpx\sample-set-1\gpx-1-8pts.json | 1094 | 754 | 704 | 655 |
| gpx\sample-set-1\gpx-1-90pts.json | 9942 | 6658 | 5952 | 5609 |
| gpx\sample-set-1\gpx-1-9pts.json | 1206 | 826 | 768 | 716 |
| json-generator.com\2015-01-06\01.json | 1103353 | 490133 | 351756 | 310012 |
| json-generator.com\2015-01-06\02.json | 2203693 | 979469 | 703115 | 606056 |
| json-generator.com\2015-01-06\03.json | 3238056 | 1438370 | 1032056 | 881484 |
| json-generator.com\2015-01-06\04.json | 4320187 | 1918771 | 1376620 | 1168143 |
| json-generator.com\2015-01-06\05.json | 5425885 | 2409849 | 1728913 | 1461451 |
| json-generator.com\2015-01-06\06.json | 6509681 | 2890828 | 2073670 | 1749445 |
| json-generator.com\2015-01-06\07.json | 7620054 | 3383755 | 2427181 | 2044025 |
| json-generator.com\2015-01-06\08.json | 8880856 | 3943588 | 2828669 | 2379084 |
| json-generator.com\2015-01-06\09.json | 9982416 | 4433013 | 3179808 | 2672229 |
| json-generator.com\2015-01-06\10.json | 11080993 | 4920626 | 3529384 | 2965358 |
| openweathermap.org\sample-set-1\owm-1-1000cities.json | 622540 | 514167 | 311697 | 223442 |
| openweathermap.org\sample-set-1\owm-1-100cities.json | 62024 | 51074 | 30877 | 23032 |
| openweathermap.org\sample-set-1\owm-1-10cities.json | 6170 | 5069 | 3205 | 2629 |
| openweathermap.org\sample-set-1\owm-1-1cities.json | 615 | 502 | 464 | 486 |
| openweathermap.org\sample-set-1\owm-1-200cities.json | 123811 | 101857 | 61272 | 44954 |
| openweathermap.org\sample-set-1\owm-1-2cities.json | 1231 | 1011 | 773 | 726 |
| openweathermap.org\sample-set-1\owm-1-300cities.json | 185699 | 152787 | 91855 | 67573 |
| openweathermap.org\sample-set-1\owm-1-400cities.json | 247718 | 203877 | 122640 | 90258 |
| openweathermap.org\sample-set-1\owm-1-500cities.json | 309532 | 254791 | 153303 | 112848 |
| openweathermap.org\sample-set-1\owm-1-50cities.json | 31048 | 25557 | 15534 | 11820 |
| openweathermap.org\sample-set-1\owm-1-5cities.json | 3136 | 2587 | 1728 | 1535 |
| openweathermap.org\sample-set-1\owm-1-600cities.json | 371839 | 306314 | 184489 | 133633 |
| openweathermap.org\sample-set-1\owm-1-700cities.json | 433746 | 357313 | 215231 | 156390 |
| openweathermap.org\sample-set-1\owm-1-800cities.json | 498084 | 411365 | 249407 | 179022 |
| openweathermap.org\sample-set-1\owm-1-900cities.json | 560315 | 462826 | 280620 | 201229 |
On average "EXI4JSON" is about 48% of the original JSON filesize! On average "EXI4JSON" is about 50% smaller than the CBOR binary encoded file!
