Package com.ibm.portal.streaming.json

This package defines an API for writing and parsing JSON in a stream based manner.

See:
Description

Interface Summary

DefaultJsonContentHandler	Convenience interface to the JsonContentHandler that allows to write high-level java objects.
JsonContentHandler	Content handler that defines events for JSON data structures.
JsonContentHandlerEx
JsonContentHandlerProvider	Interface on a class that manages JsonContentHandler callbacks.
JsonDocumentContentHandler	Implementation of a JsonContentHandler that builds a document graph out of a sequence of JSON callbacks.
JSONHandler	Deprecated. use JsonContentHandler instead
JSONHandlerFactory	Factory that generates handlers for producing and parsing JSON events in a stream based manner.
JsonProducer	Represents a buffered JSON stream that can be copied onto
JSONReader	Deprecated. use JsonParserReader instead
JsonStream	Base interface for JSON streams

Class Summary

EmptyJsonHandler	Deprecated. use EmptyJsonContentHandler instead
JSONInputSource	Deprecated.
JsonParserOutputStream	Parser that decomposes a JSON stream into callbacks to JsonContentHandler.
JsonParserReader	Implementation of a pull parser to decode JSON data as defined in RFC 4627.
JsonParserReader.Entry	Represents an entry in this input stream.
JsonParserWriter	Parser that decomposes a JSON stream into callbacks to JsonContentHandler.

Enum Summary

JsonParserReader.TYPE

Type of the next entry

Package com.ibm.portal.streaming.json Description

This package defines an API for writing and parsing JSON in a stream based manner.

Example for writing a simple JSON document:

   final JSONHandlerFactory fct = getJSONHandlerFactory();
   final Writer writer = new OutputStreamWriter(System.out, "UTF-8");
   final DefaultJsonContentHandler handler = fct.createJsonContentHandler(writer);
   handler.startDocument();
   handler.startObject();
   handler.jsonMember("id", 3);
   handler.jsonMember("unique-name", "number three");
   handler.startMember("preferences");
   handler.jsonArray(new String[]{"portal", "portlet"});
   handler.endMember();
   handler.endObject();
   handler.endDocument();
   writer.flush();
   writer.close();

This would give the following output:

{
        "id": 3,
        "unique-name": "number three",
        "preferences": ["portal", "portlet"]
}

Example for parsing the above mentioned simple JSON document:

        public void parse() throws Exception {
        final String json = "{\"id\":3,\"unique-name\":\"number three\",\"preferences\":[\"portal\",\"portlet\"]}";
        final StringReader reader = new StringReader(json);
        final JsonParserReader parser = fct.createJsonParserReader(reader);
        List<SampleJsonObject> objects = null;
        SampleJsonObject current = null;
        String s;
        for (JsonParserReader.Entry e = parser.getNextEntry(); e != null; e = parser.getNextEntry()) {
            switch (e.getType()) {
            case START_OBJECT:
                current = new SampleJsonObject();
                break;
            case START_MEMBER:
                s = e.readString();
                if ("id".equals(s)) {
                    e = parser.getNextEntry();
                    final Number number = e.readNumber();
                    current.setId(number.intValue());
                } else if ("unique-name".equals(s)) {
                    e = parser.getNextEntry();
                    final String uniqueName = e.readString();
                    current.setUniqueName(uniqueName);
                } else if ("preferences".equals(s)) {
                    final Collection<String> preferences = parsePreferences(parser);
                    current.setPreferences(preferences);
                }
                break;
            case END_OBJECT:
                objects.add(current);
                current = null;
                break;
            case START_DOCUMENT:
                objects = new ArrayList<SampleJsonObject>();
                break;
            case END_DOCUMENT:
                System.out.println("Read these objects: " + objects);
                break;
            default:
                break;
            }
        }
        parser.close();
    }

    private Collection<String> parsePreferences(final JsonParserReader parser) throws IOException {
        Collection<String> preferences = null;
        for (JsonParserReader.Entry e = parser.getNextEntry(); e != null; e = parser.getNextEntry()) {
            switch (e.getType()) {
            case START_ARRAY:
                preferences = new ArrayList<String>();
                break;
            case END_ARRAY:
                // We finished
                return preferences;
            case START_STRING:
                preferences.add(e.readString());
                break;
            }
        }
        return null;
    }

    static class SampleJsonObject {
        private int id;
        private String uniqueName;
        private Collection<String> preferences;

        /**
         * @return the id
         */
        public int getId() {
            return id;
        }

        /**
         * @param id
         *            the id to set
         */
        public void setId(int id) {
            this.id = id;
        }

        /**
         * @return the uniqueName
         */
        public String getUniqueName() {
            return uniqueName;
        }

        /**
         * @param uniqueName
         *            the uniqueName to set
         */
        public void setUniqueName(String uniqueName) {
            this.uniqueName = uniqueName;
        }

        /**
         * @return the preferences
         */
        public Collection<String> getPreferences() {
            return preferences;
        }

        /**
         * @param preferences
         *            the preferences to set
         */
        public void setPreferences(Collection<String> preferences) {
            this.preferences = preferences;
        }

        /*
         * (non-Javadoc)
         * 
         * @see java.lang.Object#toString()
         */