Pasquale Celardo - 2017-12-21

Hi to everyone, i'm using the jgrib library for read a grib file, at the moment i reading only metadat.
this is my output:

GRIB record:
    IS section:
        Grib Edition 1
        length: 2798 bytes
    PDS header:
        center: 7
        subcenter: 0
        table: 2
        grid_id: 255
        time: 23.12.2017  18:0 (dd.mm.yyyy hh:mm) 
        Type: perpw
        Description: Primary wave mean period
        Unit: s
        table: 2
        table version: 2
        Level description:
            parameter id: 1
            name: surface
            description: surface
            units: 
            short descr: surface
            increasing up?: true
            single layer?: true
            value1: 0.0
            value2: 0.0
        dec.scale: 2
        GDS exists
        BMS exists
    GDS section:
        LatLon Grid  (57x39)
        lon: 180.0 to 250.0  (dx 1.25)
        lat: 22.0 to 60.0  (dy 1.0)
    BMS section:
        bitmap length: 2223
    BDS section:
        min/max value: 4.68 18.83
        ref. value: 468.0
        is a constant: false
        bin. scale: 0
        num bits: 11

How can read a really data behind the metadata ?
Thanks in advance.