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Diffstat (limited to 'HDF5Examples/JAVA/H5J/HDF5DatasetRead.java')
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diff --git a/HDF5Examples/JAVA/H5J/HDF5DatasetRead.java b/HDF5Examples/JAVA/H5J/HDF5DatasetRead.java new file mode 100644 index 0000000..e0771a8 --- /dev/null +++ b/HDF5Examples/JAVA/H5J/HDF5DatasetRead.java @@ -0,0 +1,235 @@ +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * Copyright by The HDF Group. * + * Copyright by the Board of Trustees of the University of Illinois. * + * All rights reserved. * + * * + * This file is part of HDF5. The full HDF5 copyright notice, including * + * terms governing use, modification, and redistribution, is contained in * + * the COPYING file, which can be found at the root of the source code * + * distribution tree, or in https://www.hdfgroup.org/licenses. * + * If you do not have access to either file, you may request a copy from * + * help@hdfgroup.org. * + * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ + +import hdf.hdf5lib.H5; +import hdf.hdf5lib.HDF5Constants; + +/** + * <p> + * Title: HDF Native Package (Java) Example + * </p> + * <p> + * Description: this example shows how to read/write HDF datasets using the + * "HDF Native Package (Java)". The example creates an integer dataset, and read + * and write data values: + * + * <pre> + * "/" (root) + * 2D 32-bit integer 20x10 + * </pre> + * + * </p> + */ +public class HDF5DatasetRead { + private static String fname = "HDF5DatasetRead.h5"; + private static String dsname = "2D 32-bit integer 20x10"; + private static long[] dims2D = {20, 10}; + + private static void ReadWriteDataset() + { + long file_id = HDF5Constants.H5I_INVALID_HID; + long dataset_id = HDF5Constants.H5I_INVALID_HID; + + // create the file and add groups and dataset into the file + try { + createFile(); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Open file using the default properties. + try { + file_id = H5.H5Fopen(fname, HDF5Constants.H5F_ACC_RDWR, HDF5Constants.H5P_DEFAULT); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Open dataset using the default properties. + try { + if (file_id >= 0) + dataset_id = H5.H5Dopen(file_id, dsname, HDF5Constants.H5P_DEFAULT); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Allocate array of pointers to two-dimensional arrays (the + // elements of the dataset. + int[][] dataRead = new int[(int)dims2D[0]][(int)(dims2D[1])]; + + try { + if (dataset_id >= 0) + H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, + HDF5Constants.H5S_ALL, HDF5Constants.H5P_DEFAULT, dataRead); + } + catch (Exception e) { + e.printStackTrace(); + } + + // print out the data values + System.out.println("\n\nOriginal Data Values"); + for (int i = 0; i < 20; i++) { + System.out.print("\n" + dataRead[i][0]); + for (int j = 1; j < 10; j++) { + System.out.print(", " + dataRead[i][j]); + } + } + + // change data value and write it to file. + for (int i = 0; i < 20; i++) { + for (int j = 0; j < 10; j++) { + dataRead[i][j]++; + } + } + + // Write the data to the dataset. + try { + if (dataset_id >= 0) + H5.H5Dwrite(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, + HDF5Constants.H5S_ALL, HDF5Constants.H5P_DEFAULT, dataRead); + } + catch (Exception e) { + e.printStackTrace(); + } + + // reload the data value + int[][] dataModified = new int[(int)dims2D[0]][(int)(dims2D[1])]; + + try { + if (dataset_id >= 0) + H5.H5Dread(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, + HDF5Constants.H5S_ALL, HDF5Constants.H5P_DEFAULT, dataModified); + } + catch (Exception e) { + e.printStackTrace(); + } + + // print out the modified data values + System.out.println("\n\nModified Data Values"); + for (int i = 0; i < 20; i++) { + System.out.print("\n" + dataModified[i][0]); + for (int j = 1; j < 10; j++) { + System.out.print(", " + dataModified[i][j]); + } + } + + // Close the dataset. + try { + if (dataset_id >= 0) + H5.H5Dclose(dataset_id); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Close the file. + try { + if (file_id >= 0) + H5.H5Fclose(file_id); + } + catch (Exception e) { + e.printStackTrace(); + } + } + + /** + * create the file and add groups ans dataset into the file, which is the + * same as javaExample.H5DatasetCreate + * + * @see HDF5DatasetCreate.H5DatasetCreate + * @throws Exception + */ + private static void createFile() throws Exception + { + long file_id = HDF5Constants.H5I_INVALID_HID; + long dataspace_id = HDF5Constants.H5I_INVALID_HID; + long dataset_id = HDF5Constants.H5I_INVALID_HID; + + // Create a new file using default properties. + try { + file_id = H5.H5Fcreate(fname, HDF5Constants.H5F_ACC_TRUNC, HDF5Constants.H5P_DEFAULT, + HDF5Constants.H5P_DEFAULT); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Create the data space for the dataset. + try { + dataspace_id = H5.H5Screate_simple(2, dims2D, null); + } + catch (Exception e) { + e.printStackTrace(); + } + + // Create the dataset. + try { + if ((file_id >= 0) && (dataspace_id >= 0)) + dataset_id = H5.H5Dcreate(file_id, dsname, HDF5Constants.H5T_STD_I32LE, dataspace_id, + HDF5Constants.H5P_DEFAULT, HDF5Constants.H5P_DEFAULT, + HDF5Constants.H5P_DEFAULT); + } + 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(); + } + + // set the data values + int[] dataIn = new int[20 * 10]; + for (int i = 0; i < 20; i++) { + for (int j = 0; j < 10; j++) { + dataIn[i * 10 + j] = i * 100 + j; + } + } + + // Write the data to the dataset. + try { + if (dataset_id >= 0) + H5.H5Dwrite(dataset_id, HDF5Constants.H5T_NATIVE_INT, HDF5Constants.H5S_ALL, + HDF5Constants.H5S_ALL, HDF5Constants.H5P_DEFAULT, dataIn); + } + catch (Exception e) { + e.printStackTrace(); + } + + // End access to the dataset and release resources used by it. + try { + if (dataset_id >= 0) + H5.H5Dclose(dataset_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) { HDF5DatasetRead.ReadWriteDataset(); } +} |