tag	de94beb64e8eeeaa03db3a7a2461e7d01337597e
tagger	Richard Eckart de Castilho <rec@apache.org>	Sat Aug 06 17:07:06 2022 +0200
object	40731b5519bc3ef4754a3ce9fc5a2344e4c79d68

commit	40731b5519bc3ef4754a3ce9fc5a2344e4c79d68	[log] [tgz]
author	Richard Eckart de Castilho <rec@apache.org>	Wed Jul 13 12:56:05 2022 +0200
committer	Richard Eckart de Castilho <rec@apache.org>	Wed Jul 13 12:56:05 2022 +0200
tree	237349dca6192cd4f6108cefe9fab82550721196
parent	85c10347c0654cbcbf82ca13b68210a089ead8fe [diff]

tree: 237349dca6192cd4f6108cefe9fab82550721196

README.md

JSON serialization of the Apache UIMA CAS

The JSON CAS I/O implementation for use with the UIMA Java SDK allows to serialize UIMA CAS data to JSON and to de-serialize the data back from JSON again, loading it into a CAS object. The aim of this library is to facilitate the data interoperability of UIMA data across different platform and programming languages. For example, the implementation contains functionality to deal with the different character offset counting strategies used by different languages such as Java and Python.

Example

Here is a small example of a JSON CAS document from the unit test data. It is not meant to be a meaningful example, just one that shows some of the elements of the JSON format and how they are encoded. Please refer to the specification for an in-depth description.

{
  "%TYPES" : { },
  "%FEATURE_STRUCTURES" : [ {
    "%ID" : 1,
    "%TYPE" : "uima.cas.Sofa",
    "sofaNum" : 1,
    "sofaID" : "_InitialView",
    "mimeType" : "text",
    "sofaString" : "This is a test"
  }, {
    "%ID" : 2,
    "%TYPE" : "uima.tcas.Annotation",
    "@sofa" : 1,
    "begin" : 0,
    "end" : 4
  }, {
    "%ID" : 3,
    "%TYPE" : "uima.tcas.Annotation",
    "@sofa" : 1,
    "begin" : 5,
    "end" : 7
  }, {
    "%ID" : 4,
    "%TYPE" : "uima.tcas.Annotation",
    "@sofa" : 1,
    "begin" : 8,
    "end" : 9
  }, {
    "%ID" : 5,
    "%TYPE" : "uima.tcas.Annotation",
    "@sofa" : 1,
    "begin" : 10,
    "end" : 14
  }, {
    "%ID" : 6,
    "%TYPE" : "uima.tcas.DocumentAnnotation",
    "@sofa" : 1,
    "begin" : 0,
    "end" : 14,
    "language" : "x-unspecified"
  } ],
  "%VIEWS" : {
    "_InitialView" : {
      "%SOFA" : 1,
      "%MEMBERS" : [ 2, 3, 4, 5, 6 ]
    }
  }
}

Reading and writing JSON CAS

Serializing a CAS to JSON

import org.apache.uima.json.jsoncas2.JsonCas2Serializer

CAS cas = ...;
new JsonCas2Serializer().serialize(cas, new File("cas.json"));

De-serializing a CAS from JSON

import org.apache.uima.json.jsoncas2.JsonCas2Deserializer;

CAS cas = ...; // The CAS must already be prepared with the type system used by the CAS JSON file
new JsonCas2Deserializer().deserialize(new File("cas.json"), cas);

Format specification

For the format specification, please refer here.

Other UIMA JSON CAS implementations

A Python-based implementation of the UIMA JSON CAS format is available as part of the third-party DKPro Cassis library.