Addressbook/src/org/mxchange/addressbook/database/backend/csv/Base64CsvDatabaseBackend.java

   1 /*
   2  * Copyright (C) 2015 Roland Haeder
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 package org.mxchange.addressbook.database.backend.csv;
  18
  19 import java.io.DataOutput;
  20 import java.io.FileNotFoundException;
  21 import java.io.IOException;
  22 import java.io.RandomAccessFile;
  23 import java.sql.SQLException;
  24 import java.text.MessageFormat;
  25 import java.util.ArrayList;
  26 import java.util.Base64;
  27 import java.util.Iterator;
  28 import java.util.List;
  29 import org.mxchange.addressbook.FrameworkInterface;
  30 import org.mxchange.addressbook.contact.Contact;
  31 import org.mxchange.addressbook.database.backend.BaseDatabaseBackend;
  32 import org.mxchange.addressbook.database.backend.DatabaseBackend;
  33 import org.mxchange.addressbook.database.frontend.DatabaseFrontend;
  34 import org.mxchange.addressbook.database.storage.Storeable;
  35 import org.mxchange.addressbook.database.storage.csv.StoreableCsv;
  36 import org.mxchange.addressbook.exceptions.BadTokenException;
  37
  38 /**
  39  * A database backend with CSV file as storage implementation
  40  *
  41  * @author Roland Haeder
  42  */
  43 public class Base64CsvDatabaseBackend extends BaseDatabaseBackend implements DatabaseBackend {
  44
  45         /**
  46          * Output stream for this storage engine
  47          */
  48         private RandomAccessFile storageFile;
  49
  50         /**
  51          * Constructor with table name
  52          *
  53          * @param tableName Name of "table"
  54          * @param wrapper Wrapper instance to call back
  55          */
  56         public Base64CsvDatabaseBackend (final String tableName, final DatabaseFrontend wrapper) {
  57                 // Trace message
  58                 this.getLogger().trace(MessageFormat.format("tableName={0},wrapper={1}", tableName, wrapper)); //NOI18N
  59
  60                 // Debug message
  61                 this.getLogger().debug(MessageFormat.format("Trying to initialize table {0} ...", tableName)); //NOI18N
  62
  63                 // Set table name here, too
  64                 this.setTableName(tableName);
  65
  66                 // Set wrapper here
  67                 this.setWrapper(wrapper);
  68
  69                 // Construct file name
  70                 String fileName = String.format("data/table_%s.b64", tableName); //NOI18N
  71
  72                 // Debug message
  73                 this.getLogger().debug(MessageFormat.format("Trying to open file {0} ...", fileName)); //NOI18N
  74
  75                 try {
  76                         // Try to initialize the storage (file instance)
  77                         this.storageFile = new RandomAccessFile(fileName, "rw"); //NOI18N
  78                 } catch (final FileNotFoundException ex) {
  79                         // Did not work
  80                         this.getLogger().error(MessageFormat.format("File {0} cannot be opened: {1}", fileName, ex.toString())); //NOI18N
  81                         System.exit(1);
  82                 }
  83
  84                 // Output message
  85                 this.getLogger().debug(MessageFormat.format("Database for {0} has been initialized.", tableName)); //NOI18N
  86         }
  87
  88         /**
  89          * This database backend does not need to connect
  90          */
  91         @Override
  92         public void connectToDatabase () throws SQLException {
  93                 // Empty body
  94         }
  95
  96         /**
  97          * Shuts down this backend
  98          */
  99         @Override
 100         public void doShutdown () {
 101                 // Trace message
 102                 this.getLogger().trace("CALLED!"); //NOI18N
 103
 104                 try {
 105                         // Close file
 106                         this.getStorageFile().close();
 107                 } catch (final IOException ex) {
 108                         // Abort program
 109                         this.abortProgramWithException(ex);
 110                 }
 111
 112                 // Trace message
 113                 this.getLogger().trace("EXIT!"); //NOI18N
 114         }
 115
 116         /**
 117          * Some "getter" for row index from given boolean row value
 118          *
 119          * @param columnName Name of column
 120          * @param bool Boolean value to look for
 121          * @return Row index
 122          */
 123         @Override
 124         public int getRowIndexFromColumn (final String columnName, final boolean bool) {
 125                 // Trace message
 126                 this.getLogger().trace(MessageFormat.format("columnName={0},bool={1} - CALLED!", columnName, bool)); //NOI18N
 127
 128                 // Row indexes start with zero
 129                 int rowIndex = 0;
 130
 131                 // First rewind
 132                 this.rewind();
 133
 134                 // Try to find the proper row
 135                 while (!this.isEndOfFile()) {
 136                         // Read line
 137                         String line = this.readLine();
 138
 139                         // Debug message
 140                         this.getLogger().debug(MessageFormat.format("line={0}", line));
 141
 142                         // Callback the wrapper to handle parsing
 143                         try {
 144                                 Storeable storeable = this.getWrapper().parseLineToStoreable(line);
 145
 146                                 // Debug message
 147                                 this.getLogger().debug(MessageFormat.format("storeable={0}", storeable));
 148
 149                                 // Is the value qual
 150                                 if (storeable.isValueEqual(columnName, bool)) {
 151                                         // Debug message
 152                                         this.getLogger().debug(MessageFormat.format("Found storeable={0} for columnName={1} and bool={2}", storeable, columnName, bool));
 153
 154                                         // Found it
 155                                         break;
 156                                 }
 157                         } catch (final BadTokenException ex) {
 158                                 // Bad token found
 159                                 this.abortProgramWithException(ex);
 160                         }
 161
 162                         // Count up
 163                         rowIndex++;
 164                 }
 165
 166                 // Return it
 167                 return rowIndex;
 168         }
 169
 170         /**
 171          * Some "getter" for total row count
 172          *
 173          * @return Total row count
 174          */
 175         @Override
 176         public int getTotalCount () {
 177                 // Trace message
 178                 this.getLogger().trace("CALLED!"); //NOI18N
 179
 180                 try {
 181                         // Do a deprecated call
 182                         // @todo this needs rewrite!
 183                         return this.readList().size();
 184                 } catch (final BadTokenException ex) {
 185                         this.abortProgramWithException(ex);
 186                 }
 187
 188                 // Invalid return
 189                 this.getLogger().trace("Returning -1 ... : EXIT!"); //NOI18N
 190                 return -1;
 191         }
 192
 193         /**
 194          * Checks whether at least one row is found with given boolean value.
 195          *
 196          * @param columnName Column to check for boolean value
 197          * @param bool Boolean value to check
 198          * @return Whether boolean value is found and returns at least one row
 199          */
 200         @Override
 201         public boolean isRowFound (final String columnName, final boolean bool) {
 202                 // Trace message
 203                 this.getLogger().trace(MessageFormat.format("columnName={0},bool={1} - CALLED!", columnName, bool)); //NOI18N
 204
 205                 // Is at least one entry found?
 206                 if (this.getTotalCount() == 0) {
 207                         // No entry found at all
 208                         return false;
 209                 }
 210
 211                 // Default is not found
 212                 boolean isFound = false;
 213
 214                 // Firsr rewind
 215                 this.rewind();
 216
 217                 // Then loop through all lines
 218                 while (!this.isEndOfFile()) {
 219                         // Read line
 220                         String line = this.readLine();
 221
 222                         // Debug message
 223                         this.getLogger().debug(MessageFormat.format("line={0}", line));
 224
 225                         try {
 226                                 // And parse it to a Contact instance
 227                                 Contact contact = (Contact) this.getWrapper().parseLineToStoreable(line);
 228
 229                                 // Debug message
 230                                 this.getLogger().debug(MessageFormat.format("contact={0}", contact));
 231
 232                                 // This should not be null
 233                                 if (contact == null) {
 234                                         // Throw exception
 235                                         throw new NullPointerException("contact is null");
 236                                 }
 237
 238                                 // Now let the contact object check if it has such attribute
 239                                 if (contact.isValueEqual(columnName, bool)) {
 240                                         // Yes, it is set
 241                                         isFound = true;
 242                                         break;
 243                                 }
 244                         } catch (final BadTokenException ex) {
 245                                 // Don't continue with bad data
 246                                 this.abortProgramWithException(ex);
 247                         }
 248                 }
 249
 250                 // Trace message
 251                 this.getLogger().trace(MessageFormat.format("isFound={0} - EXIT!", isFound));
 252
 253                 // Return result
 254                 return isFound;
 255         }
 256
 257         /**
 258          * Gets an iterator for contacts
 259          *
 260          * @return Iterator for contacts
 261          * @throws org.mxchange.addressbook.exceptions.BadTokenException If the
 262          * underlaying method has found an invalid token
 263          */
 264         @Override
 265         public Iterator<? extends Storeable> iterator () throws BadTokenException {
 266                 // Trace message
 267                 this.getLogger().trace("CALLED!"); //NOI18N
 268
 269                 /*
 270                  * Then read the file into RAM (yes, not perfect for >1000 entries ...)
 271                  * and get a List back.
 272                  */
 273                 List<? extends Storeable> list = this.readList();
 274
 275                 // List must be set
 276                 assert (list instanceof List) : "list has not been set."; //NOI18N
 277
 278                 // Trace message
 279                 this.getLogger().trace(MessageFormat.format("list.iterator()={0} - EXIT!", list.iterator())); //NOI18N
 280
 281                 // Get iterator from list and return it
 282                 return list.iterator();
 283         }
 284
 285         /**
 286          * Get length of underlaying file
 287          *
 288          * @return Length of underlaying file
 289          */
 290         @Override
 291         public long length () {
 292                 long length = 0;
 293
 294                 try {
 295                         length = this.getStorageFile().length();
 296                         this.getLogger().debug(MessageFormat.format("length={0}", length)); //NOI18N
 297                 } catch (final IOException ex) {
 298                         // Length cannot be determined
 299                         // Abort program
 300                         this.abortProgramWithException(ex);
 301                 }
 302
 303                 // Return result
 304                 this.getLogger().trace(MessageFormat.format("length={0} : EXIT!", length)); //NOI18N
 305                 return length;
 306         }
 307
 308         /**
 309          * Reads a single row from database.
 310          *
 311          * @param rowIndex Row index (or how much to skip)
 312          * @return A Storeable instance
 313          * @throws org.mxchange.addressbook.exceptions.BadTokenException If a token
 314          * was badly formatted
 315          */
 316         @Override
 317         public Storeable readRow (final int rowIndex) throws BadTokenException {
 318                 // First rewind
 319                 this.rewind();
 320
 321                 // Intialize variables
 322                 int count = -1;
 323                 Storeable storeable = null;
 324
 325                 // Read all rows
 326                 while (!this.isEndOfFile() || (count < rowIndex)) {
 327                         // Read row
 328                         String line = this.readLine();
 329
 330                         // Debug message
 331                         this.getLogger().debug(MessageFormat.format("line={0}", line));
 332
 333                         // Callback the wrapper to handle parsing
 334                         storeable = this.getWrapper().parseLineToStoreable(line);
 335
 336                         // Debug message
 337                         this.getLogger().debug(MessageFormat.format("storeable={0}", storeable));
 338
 339                         // Increment counter
 340                         count++;
 341                 }
 342
 343                 // Trace message
 344                 this.getLogger().trace(MessageFormat.format("storeable={0} - EXIT!", storeable));
 345                 // Return found element
 346                 return storeable;
 347         }
 348
 349         /**
 350          * Rewinds backend
 351          */
 352         @Override
 353         public void rewind () {
 354                 // Trace message
 355                 this.getLogger().trace("CALLED!"); //NOI18N
 356
 357                 try {
 358                         // Rewind underlaying database file
 359                         this.getStorageFile().seek(0);
 360                 } catch (final IOException ex) {
 361                         // Abort program
 362                         this.abortProgramWithException(ex);
 363                 }
 364
 365                 // Trace message
 366                 this.getLogger().trace("EXIT!"); //NOI18N
 367         }
 368
 369         /**
 370          * Stores given object by "visiting" it
 371          *
 372          * @param object An object implementing Storeable
 373          * @throws java.io.IOException From "inner" class
 374          */
 375         @Override
 376         public void store (final Storeable object) throws IOException {
 377                 // Trace message
 378                 this.getLogger().trace(MessageFormat.format("object={0} - CALLED!", object)); //NOI18N
 379
 380                 // Object must not be null
 381                 if (object == null) {
 382                         // Abort here
 383                         throw new NullPointerException("object is null"); //NOI18N
 384                 }
 385
 386                 // Make sure the instance is there (DataOutput flawor)
 387                 assert (this.storageFile instanceof DataOutput);
 388
 389                 // Try to cast it, this will fail if the interface is not implemented
 390                 StoreableCsv csv = (StoreableCsv) object;
 391
 392                 // Now get a string from the object that needs to be stored
 393                 String str = csv.getCsvStringFromStoreableObject();
 394
 395                 // Debug message
 396                 this.getLogger().debug(MessageFormat.format("str({0})={1}", str.length(), str)); //NOI18N
 397
 398                 // Encode line in BASE-64
 399                 byte[] encoded = Base64.getEncoder().encode(str.getBytes());
 400
 401                 // The string is now a valid CSV string
 402                 this.getStorageFile().write(encoded);
 403
 404                 // Trace message
 405                 this.getLogger().trace("EXIT!"); //NOI18N
 406         }
 407
 408         /**
 409          * Adds given contact to list
 410          *
 411          * @param instance An instance of FrameworkInterface to add
 412          * @param list List instance
 413          */
 414         private void addToList (final Storeable instance, final List<Storeable> list) {
 415                 // Trace message
 416                 this.getLogger().trace(MessageFormat.format("contact={0} - CALLED!", instance)); //NOI18N
 417
 418                 // No null here
 419                 if (instance == null) {
 420                         // Throw exception
 421                         throw new NullPointerException("contact is null"); //NOI18N
 422                 } else if (list == null) {
 423                         // Throw exception
 424                         throw new NullPointerException("list is null"); //NOI18N
 425                 }
 426
 427                 // Debug message
 428                 this.getLogger().debug(MessageFormat.format("contact={0}", instance)); //NOI18N
 429
 430                 // Is the contact read?
 431                 if (instance instanceof FrameworkInterface) {
 432                         // Then add it
 433                         boolean added = list.add(instance);
 434
 435                         // Debug message
 436                         this.getLogger().debug(MessageFormat.format("contact={0} added={1}", instance, added)); //NOI18N
 437
 438                         // Has it been added?
 439                         if (!added) {
 440                                 // Not added
 441                                 this.getLogger().warn("Contact object has not been added."); //NOI18N
 442                         }
 443                 }
 444
 445                 // Trace message
 446                 this.getLogger().trace("EXIT!"); //NOI18N
 447         }
 448
 449         /**
 450          * Returns storage file
 451          *
 452          * @return Storage file instance
 453          */
 454         private RandomAccessFile getStorageFile () {
 455                 return this.storageFile;
 456         }
 457
 458         /**
 459          * Checks whether end of file has been reached
 460          *
 461          * @return Whether lines are left to read
 462          */
 463         private boolean isEndOfFile () {
 464                 // Default is EOF
 465                 boolean isEof = true;
 466
 467                 try {
 468                         isEof = (this.getStorageFile().getFilePointer() >= this.length());
 469                 } catch (final IOException ex) {
 470                         // Length cannot be determined
 471                         this.getLogger().catching(ex);
 472                 }
 473
 474                 // Return status
 475                 this.getLogger().trace(MessageFormat.format("isEof={0} : EXIT!", isEof)); //NOI18N
 476                 return isEof;
 477         }
 478
 479         /**
 480          * Reads a line from file base
 481          *
 482          * @return Read line from file
 483          */
 484         private String readLine () {
 485                 // Trace message
 486                 this.getLogger().trace("CALLED!"); //NOI18N
 487
 488                 // Init input
 489                 String input = null;
 490
 491                 try {
 492                         // Read single line
 493                         String base64 = this.getStorageFile().readLine();
 494
 495                         // Is the line null?
 496                         if (base64 == null) {
 497                                 // Then throw NPE here
 498                                 throw new NullPointerException("base64 is null");
 499                         }
 500
 501                         // Decode BASE-64
 502                         byte[] decoded = Base64.getDecoder().decode(base64);
 503
 504                         // Convert to string
 505                         input = new String(decoded);
 506                 } catch (final IOException ex) {
 507                         this.getLogger().catching(ex);
 508                 }
 509
 510                 // Trace message
 511                 this.getLogger().trace(MessageFormat.format("input={0} - EXIT!", input)); //NOI18N
 512
 513                 // Return read string or null
 514                 return input;
 515         }
 516
 517         /**
 518          * Reads the database file, if available, and adds all read lines into the
 519          * list.
 520          *
 521          * @return A list with Contact instances
 522          */
 523         private List<? extends Storeable> readList () throws BadTokenException {
 524                 this.getLogger().trace("CALLED!"); //NOI18N
 525
 526                 // First rewind
 527                 this.rewind();
 528
 529                 // Get file size and divide it by 140 (possible average length of one line)
 530                 int lines = Math.round(this.length() / 140 + 0.5f);
 531
 532                 // Debug message
 533                 this.getLogger().debug(MessageFormat.format("lines={0}", lines)); //NOI18N
 534
 535                 // Instance list
 536                 // @TODO The maximum length could be guessed from file size?
 537                 List<Storeable> list = new ArrayList<>(lines);
 538
 539                 // Init variables
 540                 String line;
 541                 Storeable instance = null;
 542
 543                 // Read all lines
 544                 while (!this.isEndOfFile()) {
 545                         // Then read a line
 546                         line = this.readLine();
 547
 548                         // Parse line
 549                         instance = this.getWrapper().parseLineToStoreable(line);
 550
 551                         // The contact instance should be there now
 552                         assert (instance instanceof FrameworkInterface) : MessageFormat.format("instance is not set: {0}", instance); //NOI18N
 553
 554                         // Add contact
 555                         this.addToList(instance, list);
 556                 }
 557
 558                 // Return finished list
 559                 this.getLogger().trace(MessageFormat.format("list.size()={0} : EXIT!", list.size())); //NOI18N
 560                 return list;
 561         }
 562 }