1 | import java.io.*;
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2 | import java.util.ArrayList;
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3 | import java.util.List;
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4 |
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5 | /**
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6 | * @author Riste Stojanov
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7 | */
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8 | public class ExamIo {
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9 |
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10 | public static void main(String[] args) throws IOException {
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11 | File f = new File(".");
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12 | System.out.println(f.getAbsolutePath());
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13 | ExamIo instance = new ExamIo();
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14 | instance.copyLargeTxtFiles("unexisting", "data/to", 20);
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15 |
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16 | instance.copyLargeTxtFiles("data/CsvToOrderedBinaryDatabase.csv", "data/to", 20);
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17 |
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18 |
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19 | instance.copyLargeTxtFiles("data/from", "data/to", 20);
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20 |
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21 | List<byte[]> data = new ArrayList<>();
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22 | data.add("123".getBytes());
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23 | data.add("234".getBytes());
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24 | data.add("456".getBytes());
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25 | data.add("789".getBytes());
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26 | data.add("901".getBytes());
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27 |
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28 | instance.serializeData("data/dest.bin", data);
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29 | byte[] el = instance.deserializeDataAtPosition("data/dest.bin", 3, 3);
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30 | System.out.println(new String(el));
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31 |
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32 | el = instance.deserializeDataAtPosition("data/dest.bin", 1, 3);
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33 | System.out.println(new String(el));
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34 |
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35 |
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36 | }
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37 |
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38 |
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39 | public void serializeData(String destination, List<byte[]> data) throws IOException {
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40 | File f = new File(destination);
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41 | System.out.println(f.getAbsolutePath());
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42 | f.createNewFile();
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43 | try (FileOutputStream fos = new FileOutputStream(f, false)) {
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44 | for (byte[] el : data) {
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45 | for (byte b : el) {
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46 | fos.write((int) b);
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47 | }
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48 | }
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49 | }
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50 | }
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51 |
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52 | public byte[] deserializeDataAtPosition(String source,
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53 | long position,
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54 | long elementLength) throws IOException {
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55 | try (
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56 | RandomAccessFile raf = new RandomAccessFile(source, "r")
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57 | ) {
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58 | raf.seek(position * elementLength);
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59 | byte[] el = new byte[(int) elementLength];
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60 |
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61 | int elPos = 0;
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62 | while (elPos < elementLength) {
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63 | el[elPos] = (byte) raf.read();
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64 | if (el[elPos] == -1) {
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65 | throw new IllegalStateException("Not enough bytes for the element");
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66 | }
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67 | elPos++;
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68 | }
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69 | return el;
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70 | }
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71 | }
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72 |
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73 | public void copyLargeTxtFiles(String from,
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74 | String to,
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75 | long size) {
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76 |
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77 | try {
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78 | File fromDir = validateFrom(from);
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79 |
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80 | File toDir = createUnexistingTo(to);
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81 |
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82 | moveLargeTxtFiles(fromDir, toDir, size);
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83 | } catch (Exception e) {
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84 | System.err.println(e.getMessage());
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85 | e.printStackTrace();
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86 | }
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87 |
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88 | }
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89 |
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90 | private void moveLargeTxtFiles(File fromDir, File toDir, long size) {
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91 | File[] largeTxtFiles = fromDir.listFiles(new FileFilter() {
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92 |
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93 | @Override
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94 | public boolean accept(File childFile) {
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95 | if (childFile.isFile() &&
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96 | childFile.getName().endsWith(".txt") &&
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97 | childFile.length() > size) {
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98 | return true;
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99 | } else if (childFile.isDirectory()) {
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100 | moveLargeTxtFiles(childFile, toDir, size);
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101 | }
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102 | return false;
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103 | }
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104 | });
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105 |
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106 | for (File f : largeTxtFiles) {
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107 | copyFileContent(f, toDir);
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108 | }
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109 |
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110 | }
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111 |
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112 | private void copyFileContent(File f, File toDir) {
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113 | try (
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114 | FileInputStream fis = new FileInputStream(f);
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115 | FileOutputStream fos = new FileOutputStream(new File(toDir, f.getName()))
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116 | ) {
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117 | int b;
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118 | while ((b = fis.read()) != -1) {
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119 | fos.write(b);
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120 | }
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121 | } catch (IOException e) {
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122 | e.printStackTrace();
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123 | }
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124 | }
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125 |
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126 | private File createUnexistingTo(String to) {
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127 | File toDir = new File(to);
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128 | if (!toDir.exists()) {
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129 | toDir.mkdirs();
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130 | } else if (!toDir.isDirectory()) {
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131 | throw new IllegalStateException(to + " ne e direktorium");
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132 | }
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133 |
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134 | return toDir;
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135 | }
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136 |
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137 | private File validateFrom(String from) {
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138 |
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139 | File fromDir = new File(from);
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140 | if (!fromDir.exists()) {
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141 |
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142 | throw new IllegalArgumentException("Ne postoi: " + fromDir.getAbsolutePath());
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143 | }
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144 | if (!fromDir.isDirectory()) {
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145 | throw new IllegalArgumentException("Ne e direktorium");
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146 |
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147 | }
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148 | return fromDir;
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149 | }
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150 | } |
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