Example usage for javax.json.stream JsonGeneratorFactory createGenerator

Introduction

In this page you can find the example usage for javax.json.stream JsonGeneratorFactory createGenerator.

Prototype

JsonGenerator createGenerator(OutputStream out);

Source Link

Document

Creates a JSON generator to write JSON text to a byte stream.

Usage

From source file:edu.harvard.hms.dbmi.bd2k.irct.ws.rs.resultconverter.JSONTabularDataConverter.java

@Override
public StreamingOutput createStream(final Result result) {
    StreamingOutput stream = new StreamingOutput() {
        @Override// www  .  j av  a 2s  . co  m
        public void write(OutputStream outputStream) throws IOException, WebApplicationException {
            JsonGenerator jg = null;
            ResultSet rs = null;
            try {
                rs = (ResultSet) result.getData();
                rs.load(result.getResultSetLocation());
                Map<String, Object> properties = new HashMap<String, Object>(1);
                JsonGeneratorFactory jgf = Json.createGeneratorFactory(properties);
                jg = jgf.createGenerator(outputStream);

                jg.writeStartObject(); //Start Object
                jg.writeStartArray("columns");

                // Get columns
                for (Column column : rs.getColumns()) {
                    jg.write(column.toJson());
                }
                jg.writeEnd(); //End columns
                jg.writeStartArray("data");

                rs.beforeFirst();
                while (rs.next()) {
                    jg.writeStartArray(); //Begin Row Array
                    for (int columnIndex = 0; columnIndex < rs.getColumnSize(); columnIndex++) {
                        String value = rs.getString(columnIndex);
                        if (value != null) {
                            jg.writeStartObject();
                            jg.write(rs.getColumn(columnIndex).getName(), rs.getString(columnIndex));
                            jg.writeEnd();
                        }

                    }
                    jg.writeEnd(); //End Row Array
                }

                jg.writeEnd(); //End data
                jg.writeEnd(); //End Full Object

            } catch (ResultSetException | PersistableException e) {
                log.info("Error creating JSON Stream: " + e.getMessage());
            } finally {

                if (jg != null) {
                    jg.close();
                }
                if (rs != null && !rs.isClosed()) {
                    try {
                        rs.close();
                    } catch (ResultSetException e) {
                        e.printStackTrace();
                    }
                }

                if (outputStream != null) {
                    outputStream.close();
                }
            }

        }
    };
    return stream;
}

---