H5Ex_T_IntegerAttribute.java

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 * Copyright by The HDF Group.                                               *
 * All rights reserved.                                                      *
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/************************************************************
  This example shows how to read and write integer datatypes
  to an attribute.  The program first writes integers to an
  attribute with a dataspace of DIM0xDIM1, then closes the
  file.  Next, it reopens the file, reads back the data, and
  outputs it to the screen.
 ************************************************************/

import java.text.DecimalFormat;

import hdf.hdf5lib.H5;
import hdf.hdf5lib.HDF5Constants;

public class H5Ex_T_IntegerAttribute {
    private static String FILENAME      = "H5Ex_T_IntegerAttribute.h5";
    private static String DATASETNAME   = "DS1";
    private static String ATTRIBUTENAME = "A1";
    private static final int DIM0       = 4;
    private static final int DIM1       = 7;
    private static final int RANK       = 2;

    private static void CreateDataset()
    {
        long file_id      = HDF5Constants.H5I_INVALID_HID;
        long dataspace_id = HDF5Constants.H5I_INVALID_HID;
        long dataset_id   = HDF5Constants.H5I_INVALID_HID;
        long attribute_id = HDF5Constants.H5I_INVALID_HID;
        long[] dims       = {DIM0, DIM1};
        int[][] dset_data = new int[DIM0][DIM1];

        // Initialize data.
        for (int indx = 0; indx < DIM0; indx++)
            for (int jndx = 0; jndx < DIM1; jndx++) {
                dset_data[indx][jndx] = indx * jndx - jndx;
            }

        // Create a new file using default properties.
        try {
            file_id = H5.H5Fcreate(FILENAME, HDF5Constants.H5F_ACC_TRUNC, HDF5Constants.H5P_DEFAULT,
                                   HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create dataset with a scalar dataspace.
        try {
            dataspace_id = H5.H5Screate(HDF5Constants.H5S_SCALAR);
            if (dataspace_id >= 0) {
                dataset_id = H5.H5Dcreate(file_id, DATASETNAME, HDF5Constants.H5T_STD_I32LE, dataspace_id,
                                          HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT,
                                          HDF5Constants.H5P_DEFAULT);
                H5.H5Sclose(dataspace_id);
                dataspace_id = HDF5Constants.H5I_INVALID_HID;
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create dataspace. Setting maximum size to NULL sets the maximum
        // size to be the current size.
        try {
            dataspace_id = H5.H5Screate_simple(RANK, dims, null);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create the attribute and write the array data to it.
        try {
            if ((dataset_id >= 0) && (dataspace_id >= 0))
                attribute_id =
                    H5.H5Acreate(dataset_id, ATTRIBUTENAME, HDF5Constants.H5T_STD_I64BE, dataspace_id,
                                 HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Write the dataset.
        try {
            if (attribute_id >= 0)
                H5.H5Awrite(attribute_id, HDF5Constants.H5T_NATIVE_INT, dset_data);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // End access to the dataset and release resources used by it.
        try {
            if (attribute_id >= 0)
                H5.H5Aclose(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                H5.H5Dclose(dataset_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Terminate access to the data space.
        try {
            if (dataspace_id >= 0)
                H5.H5Sclose(dataspace_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Close the file.
        try {
            if (file_id >= 0)
                H5.H5Fclose(file_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void ReadDataset()
    {
        long file_id      = HDF5Constants.H5I_INVALID_HID;
        long dataspace_id = HDF5Constants.H5I_INVALID_HID;
        long dataset_id   = HDF5Constants.H5I_INVALID_HID;
        long attribute_id = HDF5Constants.H5I_INVALID_HID;
        long[] dims       = {DIM0, DIM1};
        int[][] dset_data;

        // Open an existing file.
        try {
            file_id = H5.H5Fopen(FILENAME, HDF5Constants.H5F_ACC_RDONLY, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Open an existing dataset.
        try {
            if (file_id >= 0)
                dataset_id = H5.H5Dopen(file_id, DATASETNAME, HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                attribute_id = H5.H5Aopen_by_name(dataset_id, ".", ATTRIBUTENAME, HDF5Constants.H5P_DEFAULT,
                                                  HDF5Constants.H5P_DEFAULT);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Get dataspace and allocate memory for read buffer.
        try {
            if (attribute_id >= 0)
                dataspace_id = H5.H5Aget_space(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataspace_id >= 0)
                H5.H5Sget_simple_extent_dims(dataspace_id, dims, null);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Allocate array of pointers to two-dimensional arrays (the
        // elements of the dataset.
        dset_data = new int[(int)dims[0]][(int)(dims[1])];

        // Read data.
        try {
            if (attribute_id >= 0)
                H5.H5Aread(attribute_id, HDF5Constants.H5T_NATIVE_INT, dset_data);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Output the data to the screen.
        DecimalFormat df = new DecimalFormat("#,##0");
        System.out.println(ATTRIBUTENAME + ":");
        for (int indx = 0; indx < dims[0]; indx++) {
            System.out.print(" [");
            for (int jndx = 0; jndx < dims[1]; jndx++) {
                System.out.print(" " + df.format(dset_data[indx][jndx]));
            }
            System.out.println("]");
        }
        System.out.println();

        // End access to the dataset and release resources used by it.
        try {
            if (attribute_id >= 0)
                H5.H5Aclose(attribute_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        try {
            if (dataset_id >= 0)
                H5.H5Dclose(dataset_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Terminate access to the data space.
        try {
            if (dataspace_id >= 0)
                H5.H5Sclose(dataspace_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Close the file.
        try {
            if (file_id >= 0)
                H5.H5Fclose(file_id);
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args)
    {
        H5Ex_T_IntegerAttribute.CreateDataset();
        // Now we begin the read section of this example. Here we assume
        // the dataset and array have the same name and rank, but can have
        // any size. Therefore we must allocate a new array to read in
        // data using malloc().
        H5Ex_T_IntegerAttribute.ReadDataset();
    }
}