src/main/java/net/pterodactylus/sone/web/SearchPage.java

   1 /*
   2  * Sone - SearchPage.java - Copyright © 2010–2013 David Roden
   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
  18 package net.pterodactylus.sone.web;
  19
  20 import java.util.ArrayList;
  21 import java.util.Collection;
  22 import java.util.Collections;
  23 import java.util.Comparator;
  24 import java.util.HashSet;
  25 import java.util.List;
  26 import java.util.Set;
  27 import java.util.concurrent.TimeUnit;
  28 import java.util.logging.Level;
  29 import java.util.logging.Logger;
  30
  31 import net.pterodactylus.sone.data.Post;
  32 import net.pterodactylus.sone.data.PostReply;
  33 import net.pterodactylus.sone.data.Profile;
  34 import net.pterodactylus.sone.data.Profile.Field;
  35 import net.pterodactylus.sone.data.Reply;
  36 import net.pterodactylus.sone.data.Sone;
  37 import net.pterodactylus.sone.web.page.FreenetRequest;
  38 import net.pterodactylus.util.collection.Pagination;
  39 import net.pterodactylus.util.logging.Logging;
  40 import net.pterodactylus.util.number.Numbers;
  41 import net.pterodactylus.util.template.Template;
  42 import net.pterodactylus.util.template.TemplateContext;
  43 import net.pterodactylus.util.text.StringEscaper;
  44 import net.pterodactylus.util.text.TextException;
  45
  46 import com.google.common.base.Function;
  47 import com.google.common.base.Optional;
  48 import com.google.common.base.Predicate;
  49 import com.google.common.cache.CacheBuilder;
  50 import com.google.common.cache.CacheLoader;
  51 import com.google.common.cache.LoadingCache;
  52 import com.google.common.collect.Collections2;
  53 import com.google.common.collect.FluentIterable;
  54 import com.google.common.collect.Ordering;
  55
  56 /**
  57  * This page lets the user search for posts and replies that contain certain
  58  * words.
  59  *
  60  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  61  */
  62 public class SearchPage extends SoneTemplatePage {
  63
  64         /** The logger. */
  65         private static final Logger logger = Logging.getLogger(SearchPage.class);
  66
  67         /** Short-term cache. */
  68         private final LoadingCache<List<Phrase>, Set<Hit<Post>>> hitCache = CacheBuilder.newBuilder().expireAfterWrite(5, TimeUnit.MINUTES).build(new CacheLoader<List<Phrase>, Set<Hit<Post>>>() {
  69
  70                 @Override
  71                 @SuppressWarnings("synthetic-access")
  72                 public Set<Hit<Post>> load(List<Phrase> phrases) {
  73                         Set<Post> posts = new HashSet<Post>();
  74                         for (Sone sone : webInterface.getCore().getSones()) {
  75                                 posts.addAll(sone.getPosts());
  76                         }
  77                         return getHits(Collections2.filter(posts, Post.FUTURE_POSTS_FILTER), phrases, new PostStringGenerator());
  78                 }
  79         });
  80
  81         /**
  82          * Creates a new search page.
  83          *
  84          * @param template
  85          *            The template to render
  86          * @param webInterface
  87          *            The Sone web interface
  88          */
  89         public SearchPage(Template template, WebInterface webInterface) {
  90                 super("search.html", template, "Page.Search.Title", webInterface);
  91         }
  92
  93         //
  94         // SONETEMPLATEPAGE METHODS
  95         //
  96
  97         /**
  98          * {@inheritDoc}
  99          */
 100         @Override
 101         @SuppressWarnings("synthetic-access")
 102         protected void processTemplate(FreenetRequest request, TemplateContext templateContext) throws RedirectException {
 103                 super.processTemplate(request, templateContext);
 104                 String query = request.getHttpRequest().getParam("query").trim();
 105                 if (query.length() == 0) {
 106                         throw new RedirectException("index.html");
 107                 }
 108
 109                 List<Phrase> phrases = parseSearchPhrases(query);
 110                 if (phrases.isEmpty()) {
 111                         throw new RedirectException("index.html");
 112                 }
 113
 114                 /* check for a couple of shortcuts. */
 115                 if (phrases.size() == 1) {
 116                         String phrase = phrases.get(0).getPhrase();
 117
 118                         /* is it a Sone ID? */
 119                         redirectIfNotNull(getSoneId(phrase), "viewSone.html?sone=");
 120
 121                         /* is it a post ID? */
 122                         redirectIfNotNull(getPostId(phrase), "viewPost.html?post=");
 123
 124                         /* is it a reply ID? show the post. */
 125                         redirectIfNotNull(getReplyPostId(phrase), "viewPost.html?post=");
 126
 127                         /* is it an album ID? */
 128                         redirectIfNotNull(getAlbumId(phrase), "imageBrowser.html?album=");
 129
 130                         /* is it an image ID? */
 131                         redirectIfNotNull(getImageId(phrase), "imageBrowser.html?image=");
 132                 }
 133
 134                 Collection<Sone> sones = webInterface.getCore().getSones();
 135                 Collection<Hit<Sone>> soneHits = getHits(sones, phrases, SoneStringGenerator.COMPLETE_GENERATOR);
 136
 137                 Collection<Hit<Post>> postHits = hitCache.getUnchecked(phrases);
 138
 139                 /* now filter. */
 140                 soneHits = Collections2.filter(soneHits, Hit.POSITIVE_FILTER);
 141                 postHits = Collections2.filter(postHits, Hit.POSITIVE_FILTER);
 142
 143                 /* now sort. */
 144                 List<Hit<Sone>> sortedSoneHits = Ordering.from(Hit.DESCENDING_COMPARATOR).sortedCopy(soneHits);
 145                 List<Hit<Post>> sortedPostHits = Ordering.from(Hit.DESCENDING_COMPARATOR).sortedCopy(postHits);
 146
 147                 /* extract Sones and posts. */
 148                 List<Sone> resultSones = FluentIterable.from(sortedSoneHits).transform(new HitMapper<Sone>()).toList();
 149                 List<Post> resultPosts = FluentIterable.from(sortedPostHits).transform(new HitMapper<Post>()).toList();
 150
 151                 /* pagination. */
 152                 Pagination<Sone> sonePagination = new Pagination<Sone>(resultSones, webInterface.getCore().getPreferences().getPostsPerPage()).setPage(Numbers.safeParseInteger(request.getHttpRequest().getParam("sonePage"), 0));
 153                 Pagination<Post> postPagination = new Pagination<Post>(resultPosts, webInterface.getCore().getPreferences().getPostsPerPage()).setPage(Numbers.safeParseInteger(request.getHttpRequest().getParam("postPage"), 0));
 154
 155                 templateContext.set("sonePagination", sonePagination);
 156                 templateContext.set("soneHits", sonePagination.getItems());
 157                 templateContext.set("postPagination", postPagination);
 158                 templateContext.set("postHits", postPagination.getItems());
 159         }
 160
 161         //
 162         // PRIVATE METHODS
 163         //
 164
 165         /**
 166          * Collects hit information for the given objects. The objects are converted
 167          * to a {@link String} using the given {@link StringGenerator}, and the
 168          * {@link #calculateScore(List, String) calculated score} is stored together
 169          * with the object in a {@link Hit}, and all resulting {@link Hit}s are then
 170          * returned.
 171          *
 172          * @param <T>
 173          *            The type of the objects
 174          * @param objects
 175          *            The objects to search over
 176          * @param phrases
 177          *            The phrases to search for
 178          * @param stringGenerator
 179          *            The string generator for the objects
 180          * @return The hits for the given phrases
 181          */
 182         private static <T> Set<Hit<T>> getHits(Collection<T> objects, List<Phrase> phrases, StringGenerator<T> stringGenerator) {
 183                 Set<Hit<T>> hits = new HashSet<Hit<T>>();
 184                 for (T object : objects) {
 185                         String objectString = stringGenerator.generateString(object);
 186                         double score = calculateScore(phrases, objectString);
 187                         hits.add(new Hit<T>(object, score));
 188                 }
 189                 return hits;
 190         }
 191
 192         /**
 193          * Parses the given query into search phrases. The query is split on
 194          * whitespace while allowing to group words using single or double quotes.
 195          * Isolated phrases starting with a “+” are
 196          * {@link Phrase.Optionality#REQUIRED}, phrases with a “-” are
 197          * {@link Phrase.Optionality#FORBIDDEN}.
 198          *
 199          * @param query
 200          *            The query to parse
 201          * @return The parsed phrases
 202          */
 203         private static List<Phrase> parseSearchPhrases(String query) {
 204                 List<String> parsedPhrases = null;
 205                 try {
 206                         parsedPhrases = StringEscaper.parseLine(query);
 207                 } catch (TextException te1) {
 208                         /* invalid query. */
 209                         return Collections.emptyList();
 210                 }
 211
 212                 List<Phrase> phrases = new ArrayList<Phrase>();
 213                 for (String phrase : parsedPhrases) {
 214                         if (phrase.startsWith("+")) {
 215                                 if (phrase.length() > 1) {
 216                                         phrases.add(new Phrase(phrase.substring(1), Phrase.Optionality.REQUIRED));
 217                                 } else {
 218                                         phrases.add(new Phrase("+", Phrase.Optionality.OPTIONAL));
 219                                 }
 220                         } else if (phrase.startsWith("-")) {
 221                                 if (phrase.length() > 1) {
 222                                         phrases.add(new Phrase(phrase.substring(1), Phrase.Optionality.FORBIDDEN));
 223                                 } else {
 224                                         phrases.add(new Phrase("-", Phrase.Optionality.OPTIONAL));
 225                                 }
 226                         } else {
 227                                 phrases.add(new Phrase(phrase, Phrase.Optionality.OPTIONAL));
 228                         }
 229                 }
 230                 return phrases;
 231         }
 232
 233         /**
 234          * Calculates the score for the given expression when using the given
 235          * phrases.
 236          *
 237          * @param phrases
 238          *            The phrases to search for
 239          * @param expression
 240          *            The expression to search
 241          * @return The score of the expression
 242          */
 243         private static double calculateScore(List<Phrase> phrases, String expression) {
 244                 logger.log(Level.FINEST, String.format("Calculating Score for “%s”…", expression));
 245                 double optionalHits = 0;
 246                 double requiredHits = 0;
 247                 int forbiddenHits = 0;
 248                 int requiredPhrases = 0;
 249                 for (Phrase phrase : phrases) {
 250                         String phraseString = phrase.getPhrase().toLowerCase();
 251                         if (phrase.getOptionality() == Phrase.Optionality.REQUIRED) {
 252                                 ++requiredPhrases;
 253                         }
 254                         int matches = 0;
 255                         int index = 0;
 256                         double score = 0;
 257                         while (index < expression.length()) {
 258                                 int position = expression.toLowerCase().indexOf(phraseString, index);
 259                                 if (position == -1) {
 260                                         break;
 261                                 }
 262                                 score += Math.pow(1 - position / (double) expression.length(), 2);
 263                                 index = position + phraseString.length();
 264                                 logger.log(Level.FINEST, String.format("Got hit at position %d.", position));
 265                                 ++matches;
 266                         }
 267                         logger.log(Level.FINEST, String.format("Score: %f", score));
 268                         if (matches == 0) {
 269                                 continue;
 270                         }
 271                         if (phrase.getOptionality() == Phrase.Optionality.REQUIRED) {
 272                                 requiredHits += score;
 273                         }
 274                         if (phrase.getOptionality() == Phrase.Optionality.OPTIONAL) {
 275                                 optionalHits += score;
 276                         }
 277                         if (phrase.getOptionality() == Phrase.Optionality.FORBIDDEN) {
 278                                 forbiddenHits += matches;
 279                         }
 280                 }
 281                 return requiredHits * 3 + optionalHits + (requiredHits - requiredPhrases) * 5 - (forbiddenHits * 2);
 282         }
 283
 284         /**
 285          * Throws a
 286          * {@link net.pterodactylus.sone.web.page.FreenetTemplatePage.RedirectException}
 287          * if the given object is not {@code null}, appending the object to the
 288          * given target URL.
 289          *
 290          * @param object
 291          *            The object on which to redirect
 292          * @param target
 293          *            The target of the redirect
 294          * @throws RedirectException
 295          *             if {@code object} is not {@code null}
 296          */
 297         private static void redirectIfNotNull(String object, String target) throws RedirectException {
 298                 if (object != null) {
 299                         throw new RedirectException(target + object);
 300                 }
 301         }
 302
 303         /**
 304          * If the given phrase contains a Sone ID (optionally prefixed by
 305          * “sone://”), returns said Sone ID, otherwise return {@code null}.
 306          *
 307          * @param phrase
 308          *            The phrase that maybe is a Sone ID
 309          * @return The Sone ID, or {@code null}
 310          */
 311         private String getSoneId(String phrase) {
 312                 String soneId = phrase.startsWith("sone://") ? phrase.substring(7) : phrase;
 313                 return (webInterface.getCore().getSone(soneId).isPresent()) ? soneId : null;
 314         }
 315
 316         /**
 317          * If the given phrase contains a post ID (optionally prefixed by
 318          * “post://”), returns said post ID, otherwise return {@code null}.
 319          *
 320          * @param phrase
 321          *            The phrase that maybe is a post ID
 322          * @return The post ID, or {@code null}
 323          */
 324         private String getPostId(String phrase) {
 325                 String postId = phrase.startsWith("post://") ? phrase.substring(7) : phrase;
 326                 return (webInterface.getCore().getPost(postId).isPresent()) ? postId : null;
 327         }
 328
 329         /**
 330          * If the given phrase contains a reply ID (optionally prefixed by
 331          * “reply://”), returns the ID of the post the reply belongs to, otherwise
 332          * return {@code null}.
 333          *
 334          * @param phrase
 335          *            The phrase that maybe is a reply ID
 336          * @return The reply’s post ID, or {@code null}
 337          */
 338         private String getReplyPostId(String phrase) {
 339                 String replyId = phrase.startsWith("reply://") ? phrase.substring(8) : phrase;
 340                 Optional<PostReply> postReply = webInterface.getCore().getPostReply(replyId);
 341                 if (!postReply.isPresent()) {
 342                         return null;
 343                 }
 344                 return postReply.get().getPostId();
 345         }
 346
 347         /**
 348          * If the given phrase contains an album ID (optionally prefixed by
 349          * “album://”), returns said album ID, otherwise return {@code null}.
 350          *
 351          * @param phrase
 352          *            The phrase that maybe is an album ID
 353          * @return The album ID, or {@code null}
 354          */
 355         private String getAlbumId(String phrase) {
 356                 String albumId = phrase.startsWith("album://") ? phrase.substring(8) : phrase;
 357                 return webInterface.getCore().getAlbum(albumId).isPresent() ? albumId : null;
 358         }
 359
 360         /**
 361          * If the given phrase contains an image ID (optionally prefixed by
 362          * “image://”), returns said image ID, otherwise return {@code null}.
 363          *
 364          * @param phrase
 365          *            The phrase that maybe is an image ID
 366          * @return The image ID, or {@code null}
 367          */
 368         private String getImageId(String phrase) {
 369                 String imageId = phrase.startsWith("image://") ? phrase.substring(8) : phrase;
 370                 return webInterface.getCore().getImage(imageId).isPresent() ? imageId : null;
 371         }
 372
 373         /**
 374          * Converts a given object into a {@link String}.
 375          *
 376          * @param <T>
 377          *            The type of the objects
 378          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 379          */
 380         private static interface StringGenerator<T> {
 381
 382                 /**
 383                  * Generates a {@link String} for the given object.
 384                  *
 385                  * @param object
 386                  *            The object to generate the {@link String} for
 387                  * @return The generated {@link String}
 388                  */
 389                 public String generateString(T object);
 390
 391         }
 392
 393         /**
 394          * Generates a {@link String} from a {@link Sone}, concatenating the name of
 395          * the Sone and all {@link Profile} {@link Field} values.
 396          *
 397          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 398          */
 399         private static class SoneStringGenerator implements StringGenerator<Sone> {
 400
 401                 /** A static instance of a complete Sone string generator. */
 402                 public static final SoneStringGenerator COMPLETE_GENERATOR = new SoneStringGenerator(true);
 403
 404                 /**
 405                  * A static instance of a Sone string generator that will only use the
 406                  * name of the Sone.
 407                  */
 408                 public static final SoneStringGenerator NAME_GENERATOR = new SoneStringGenerator(false);
 409
 410                 /** Whether to generate a string from all data of a Sone. */
 411                 private final boolean complete;
 412
 413                 /**
 414                  * Creates a new Sone string generator.
 415                  *
 416                  * @param complete
 417                  *            {@code true} to use the profile’s fields, {@code false} to
 418                  *            not to use the profile‘s fields
 419                  */
 420                 private SoneStringGenerator(boolean complete) {
 421                         this.complete = complete;
 422                 }
 423
 424                 /**
 425                  * {@inheritDoc}
 426                  */
 427                 @Override
 428                 public String generateString(Sone sone) {
 429                         StringBuilder soneString = new StringBuilder();
 430                         soneString.append(sone.getName());
 431                         Profile soneProfile = sone.getProfile();
 432                         if (soneProfile.getFirstName() != null) {
 433                                 soneString.append(' ').append(soneProfile.getFirstName());
 434                         }
 435                         if (soneProfile.getMiddleName() != null) {
 436                                 soneString.append(' ').append(soneProfile.getMiddleName());
 437                         }
 438                         if (soneProfile.getLastName() != null) {
 439                                 soneString.append(' ').append(soneProfile.getLastName());
 440                         }
 441                         if (complete) {
 442                                 for (Field field : soneProfile.getFields()) {
 443                                         soneString.append(' ').append(field.getValue());
 444                                 }
 445                         }
 446                         return soneString.toString();
 447                 }
 448
 449         }
 450
 451         /**
 452          * Generates a {@link String} from a {@link Post}, concatenating the text of
 453          * the post, the text of all {@link Reply}s, and the name of all
 454          * {@link Sone}s that have replied.
 455          *
 456          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 457          */
 458         private class PostStringGenerator implements StringGenerator<Post> {
 459
 460                 /**
 461                  * {@inheritDoc}
 462                  */
 463                 @Override
 464                 public String generateString(Post post) {
 465                         StringBuilder postString = new StringBuilder();
 466                         postString.append(post.getText());
 467                         if (post.getRecipient().isPresent()) {
 468                                 postString.append(' ').append(SoneStringGenerator.NAME_GENERATOR.generateString(post.getRecipient().get()));
 469                         }
 470                         for (PostReply reply : Collections2.filter(webInterface.getCore().getReplies(post.getId()), Reply.FUTURE_REPLY_FILTER)) {
 471                                 postString.append(' ').append(SoneStringGenerator.NAME_GENERATOR.generateString(reply.getSone()));
 472                                 postString.append(' ').append(reply.getText());
 473                         }
 474                         return postString.toString();
 475                 }
 476
 477         }
 478
 479         /**
 480          * A search phrase.
 481          *
 482          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 483          */
 484         private static class Phrase {
 485
 486                 /**
 487                  * The optionality of a search phrase.
 488                  *
 489                  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’
 490                  *         Roden</a>
 491                  */
 492                 public enum Optionality {
 493
 494                         /** The phrase is optional. */
 495                         OPTIONAL,
 496
 497                         /** The phrase is required. */
 498                         REQUIRED,
 499
 500                         /** The phrase is forbidden. */
 501                         FORBIDDEN
 502
 503                 }
 504
 505                 /** The phrase to search for. */
 506                 private final String phrase;
 507
 508                 /** The optionality of the phrase. */
 509                 private final Optionality optionality;
 510
 511                 /**
 512                  * Creates a new phrase.
 513                  *
 514                  * @param phrase
 515                  *            The phrase to search for
 516                  * @param optionality
 517                  *            The optionality of the phrase
 518                  */
 519                 public Phrase(String phrase, Optionality optionality) {
 520                         this.optionality = optionality;
 521                         this.phrase = phrase;
 522                 }
 523
 524                 /**
 525                  * Returns the phrase to search for.
 526                  *
 527                  * @return The phrase to search for
 528                  */
 529                 public String getPhrase() {
 530                         return phrase;
 531                 }
 532
 533                 /**
 534                  * Returns the optionality of the phrase.
 535                  *
 536                  * @return The optionality of the phrase
 537                  */
 538                 public Optionality getOptionality() {
 539                         return optionality;
 540                 }
 541
 542                 //
 543                 // OBJECT METHODS
 544                 //
 545
 546                 /**
 547                  * {@inheritDoc}
 548                  */
 549                 @Override
 550                 public int hashCode() {
 551                         return phrase.hashCode() ^ ((optionality == Optionality.FORBIDDEN) ? (0xaaaaaaaa) : ((optionality == Optionality.REQUIRED) ? 0x55555555 : 0));
 552                 }
 553
 554                 /**
 555                  * {@inheritDoc}
 556                  */
 557                 @Override
 558                 public boolean equals(Object object) {
 559                         if (!(object instanceof Phrase)) {
 560                                 return false;
 561                         }
 562                         Phrase phrase = (Phrase) object;
 563                         return (this.optionality == phrase.optionality) && this.phrase.equals(phrase.phrase);
 564                 }
 565
 566         }
 567
 568         /**
 569          * A hit consists of a searched object and the score it got for the phrases
 570          * of the search.
 571          *
 572          * @see SearchPage#calculateScore(List, String)
 573          * @param <T>
 574          *            The type of the searched object
 575          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 576          */
 577         private static class Hit<T> {
 578
 579                 /** Filter for {@link Hit}s with a score of more than 0. */
 580                 public static final Predicate<Hit<?>> POSITIVE_FILTER = new Predicate<Hit<?>>() {
 581
 582                         @Override
 583                         public boolean apply(Hit<?> hit) {
 584                                 return (hit == null) ? false : hit.getScore() > 0;
 585                         }
 586
 587                 };
 588
 589                 /** Comparator that sorts {@link Hit}s descending by score. */
 590                 public static final Comparator<Hit<?>> DESCENDING_COMPARATOR = new Comparator<Hit<?>>() {
 591
 592                         @Override
 593                         public int compare(Hit<?> leftHit, Hit<?> rightHit) {
 594                                 return (rightHit.getScore() < leftHit.getScore()) ? -1 : ((rightHit.getScore() > leftHit.getScore()) ? 1 : 0);
 595                         }
 596
 597                 };
 598
 599                 /** The object that was searched. */
 600                 private final T object;
 601
 602                 /** The score of the object. */
 603                 private final double score;
 604
 605                 /**
 606                  * Creates a new hit.
 607                  *
 608                  * @param object
 609                  *            The object that was searched
 610                  * @param score
 611                  *            The score of the object
 612                  */
 613                 public Hit(T object, double score) {
 614                         this.object = object;
 615                         this.score = score;
 616                 }
 617
 618                 /**
 619                  * Returns the object that was searched.
 620                  *
 621                  * @return The object that was searched
 622                  */
 623                 public T getObject() {
 624                         return object;
 625                 }
 626
 627                 /**
 628                  * Returns the score of the object.
 629                  *
 630                  * @return The score of the object
 631                  */
 632                 public double getScore() {
 633                         return score;
 634                 }
 635
 636         }
 637
 638         /**
 639          * Extracts the object from a {@link Hit}.
 640          *
 641          * @param <T>
 642          *            The type of the object to extract
 643          * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
 644          */
 645         private static class HitMapper<T> implements Function<Hit<T>, T> {
 646
 647                 /**
 648                  * {@inheritDoc}
 649                  */
 650                 @Override
 651                 public T apply(Hit<T> input) {
 652                         return input.getObject();
 653                 }
 654
 655         }
 656
 657 }