Creating a HDF5 file input - Java Big Data

Java examples for Big Data:HDF

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Description

Creating a HDF5 file input

Demo Code

/******************************************************************
 * CreateFileInput.java (for HDF5 tutorial Lesson 4)
 *
 *   -- Creating a HDF5 file// w  ww  .  j  a  va2 s .c  o  m
 *      (another java conversion from h5_crtfile.c, give user two options:
 *       one for library path and one for file name, if user chooses 
 *       nothing, then the default file name is used.)
 *
 ******************************************************************/

import java.lang.System;
import java.util.*;
import ncsa.hdf.hdf5lib.*;
import ncsa.hdf.hdf5lib.exceptions.*;

public class CreateFileInput
{    
   // The run command should be like:
   // "./runCreateFileInput -l /usr/lib/hdf5.dll -f ./open.h5"
   public static void main(String []argv) 
   {  
      int file_id = -1;    // file identifier 
      int status = -1;
      String libpath = null;
      String filename = null;

      for (int i = 0; i < argv.length; i++)
      {
   if ("-l".equalsIgnoreCase (argv[i]))
      libpath = argv[++i];
   
   if ("-f".equalsIgnoreCase (argv[i]))
      filename = argv[++i];
      }
     
      if (libpath != null)
      { 
    Properties pros = System.getProperties ();
    pros.put (H5.H5PATH_PROPERTY_KEY, libpath);
    
    /*
    this function call could be used in Java 1.2
    System.setProperty (H5.H5PATH_PROPERTY_KEY, libpath);
    */
      }
      
      if (filename == null)
      {   
   filename = "file.h5"; // if no input file name, use the default name
      }

      file_id = H5Fcreate_wrap (filename, 
        HDF5Constants.H5F_ACC_TRUNC,
        HDF5Constants.H5P_DEFAULT, 
        HDF5Constants.H5P_DEFAULT);
      status = H5Fclose_wrap (filename, file_id);
   }


   // Help function for creating a new file 
   public static int H5Fcreate_wrap (String name, int flags,
             int create_id, int access_id)
   {
      int file_id = -1;    // file identifier 
      try 
      {
   // Create a new file using default file properties.
   file_id = H5.H5Fcreate (name, flags, create_id, access_id);
          
      }
      catch (HDF5Exception hdf5e)
      {
   System.out.println 
       ("CreateFileInput.H5Fcreate_wrap() with HDF5Exception: "
        + hdf5e.getMessage());
      }
      catch (Exception e)
      {
   System.out.println 
       ("CreateFileInput.H5Fcreate_wrap() with other Exception: " 
        + e.getMessage());
      }

      System.out.println ("\nThe file name is: " + name);
      System.out.println ("The file ID is: " + file_id);

      return file_id;
   }  


   // Help function for terminating access to the file. 
   public static int H5Fclose_wrap (String name, int file_id)
   {
      int status = -1;
      
      try 
      {
   // Terminate access to the file. 
   status = H5.H5Fclose (file_id);
      }
      catch (HDF5Exception hdf5e)
      { 
   System.out.println 
       ("CreateFileInput.H5Fclose_wrap() with HDF5Exception: " 
        + hdf5e.getMessage());
      }
      catch (Exception e)
      {
   System.out.println 
       ("CreateFileInput.H5Fclose_wrap() with other exception: " 
        + e.getMessage());
      }
      
      return status;
   }
}

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