H5ObjectEx_T_IntegerAttribute.java

/************************************************************
  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.
 ************************************************************/

package datatypes;

import java.text.DecimalFormat;

import hdf.object.Datatype;
import hdf.object.FileFormat;
import hdf.object.h5.H5Datatype;
import hdf.object.h5.H5File;
import hdf.object.h5.H5ScalarAttr;
import hdf.object.h5.H5ScalarDS;

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

public class H5ObjectEx_T_IntegerAttribute {
    private static String FILENAME      = "H5ObjectEx_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 void CreateDataset()
    {
        H5File file           = null;
        H5ScalarDS dset       = null;
        long dataset_id       = -1;
        long attribute_id     = -1;
        long[] dims           = {DIM0, DIM1};
        int[][] dset_data     = new int[DIM0][DIM1];
        H5Datatype typeInt    = null;
        H5Datatype typeBigInt = null;

        // 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 = new H5File(FILENAME, FileFormat.CREATE);
            file.open();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create the base datatypes.
        try {
            typeInt    = new H5Datatype(Datatype.CLASS_INTEGER, 4, Datatype.ORDER_LE, Datatype.NATIVE);
            typeBigInt = new H5Datatype(Datatype.CLASS_INTEGER, 8, Datatype.ORDER_BE, Datatype.NATIVE);
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create dataset with a scalar dataspace.
        try {
            dset = (H5ScalarDS)file.createScalarDS(DATASETNAME, null, typeInt, dims, null, null, 0, null);
            dataset_id = dset.open();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Create the attribute and write the array data to it.
        try {
            H5ScalarAttr dataArray = new H5ScalarAttr(dset, ATTRIBUTENAME, typeBigInt, dims);
            dataArray.write();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

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

        // Close the file.
        try {
            file.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void ReadDataset()
    {
        H5File file       = null;
        H5ScalarDS dset   = null;
        long dataspace_id = -1;
        long dataset_id   = -1;
        long attribute_id = -1;
        long[] dims       = {DIM0, DIM1};
        int[][] dset_data;

        // Open an existing file.
        try {
            file = new H5File(FILENAME, FileFormat.READ);
            file.open();
        }
        catch (Exception e) {
            e.printStackTrace();
        }

        // Open an existing dataset.
        try {
            dset       = (H5ScalarDS)file.get(DATASETNAME);
            dataset_id = dset.open();
        }
        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)
                dset.close(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 {
            file.close();
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args)
    {
        H5ObjectEx_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().
        H5ObjectEx_T_IntegerAttribute.ReadDataset();
    }
}