js/pz2.js

   1 /*
   2 ** $Id: pz2.js,v 1.68 2007-12-20 13:09:40 jakub Exp $
   3 ** pz2.js - pazpar2's javascript client library.
   4 */
   5
   6 //since explorer is flawed
   7 if (!window['Node']) {
   8     window.Node = new Object();
   9     Node.ELEMENT_NODE = 1;
  10     Node.ATTRIBUTE_NODE = 2;
  11     Node.TEXT_NODE = 3;
  12     Node.CDATA_SECTION_NODE = 4;
  13     Node.ENTITY_REFERENCE_NODE = 5;
  14     Node.ENTITY_NODE = 6;
  15     Node.PROCESSING_INSTRUCTION_NODE = 7;
  16     Node.COMMENT_NODE = 8;
  17     Node.DOCUMENT_NODE = 9;
  18     Node.DOCUMENT_TYPE_NODE = 10;
  19     Node.DOCUMENT_FRAGMENT_NODE = 11;
  20     Node.NOTATION_NODE = 12;
  21 }
  22
  23 // prevent execution of more than once
  24 if(typeof window.pz2 == "undefined") {
  25 window.undefined = window.undefined;
  26
  27 var pz2 = function ( paramArray )
  28 {
  29
  30     // at least one callback required
  31     if ( !paramArray )
  32         throw new Error("Pz2.js: Array with parameters has to be suplied.");
  33
  34     //supported pazpar2's protocol version
  35     this.suppProtoVer = '1';
  36     if (typeof paramArray.pazpar2path != "undefined")
  37         this.pz2String = paramArray.pazpar2path;
  38     else
  39         this.pz2String = "/pazpar2/search.pz2";
  40     this.useSessions = true;
  41
  42     this.stylesheet = paramArray.detailstylesheet || null;
  43     //load stylesheet if required in async mode
  44     if( this.stylesheet ) {
  45         var context = this;
  46         var request = new pzHttpRequest( this.stylesheet );
  47         request.get( {}, function ( doc ) { context.xslDoc = doc; } );
  48     }
  49
  50     this.errorHandler = paramArray.errorhandler || null;
  51
  52     // function callbacks
  53     this.initCallback = paramArray.oninit || null;
  54     this.statCallback = paramArray.onstat || null;
  55     this.showCallback = paramArray.onshow || null;
  56     this.termlistCallback = paramArray.onterm || null;
  57     this.recordCallback = paramArray.onrecord || null;
  58     this.bytargetCallback = paramArray.onbytarget || null;
  59     this.resetCallback = paramArray.onreset || null;
  60
  61     // termlist keys
  62     this.termKeys = paramArray.termlist || "subject";
  63
  64     // some configurational stuff
  65     this.keepAlive = 50000;
  66
  67     if ( paramArray.keepAlive < this.keepAlive )
  68         this.keepAlive = paramArray.keepAlive;
  69
  70     this.sessionID = null;
  71     this.initStatusOK = false;
  72     this.pingStatusOK = false;
  73     this.searchStatusOK = false;
  74
  75     // for sorting
  76     this.currentSort = "relevance";
  77
  78     // where are we?
  79     this.currentStart = 0;
  80     this.currentNum = 20;
  81
  82     // last full record retrieved
  83     this.currRecID = null;
  84
  85     // current query
  86     this.currQuery = null;
  87
  88     //timers
  89     this.statTime = paramArray.stattime || 1000;
  90     this.statTimer = null;
  91     this.termTime = paramArray.termtime || 1000;
  92     this.termTimer = null;
  93     this.showTime = paramArray.showtime || 1000;
  94     this.showTimer = null;
  95     this.showFastCount = 4;
  96     this.bytargetTime = paramArray.bytargettime || 1000;
  97     this.bytargetTimer = null;
  98
  99     // counters for each command and applied delay
 100     this.dumpFactor = 500;
 101     this.showCounter = 0;
 102     this.termCounter = 0;
 103     this.statCounter = 0;
 104     this.bytargetCounter = 0;
 105
 106     // active clients, updated by stat and show
 107     // might be an issue since bytarget will poll accordingly
 108     this.activeClients = 1;
 109
 110     // if in proxy mode no need to init
 111     if (paramArray.usesessions != undefined) {
 112          this.useSessions = paramArray.usesessions;
 113         this.initStatusOK = true;
 114     }
 115     // else, auto init session or wait for a user init?
 116     if (this.useSessions && paramArray.autoInit !== false) {
 117         this.init();
 118     }
 119 };
 120
 121 pz2.prototype =
 122 {
 123     //error handler for async error throws
 124    throwError: function (errMsg, errCode)
 125    {
 126         var err = new Error(errMsg);
 127         if (errCode) err.code = errCode;
 128
 129         if (this.errorHandler) {
 130             this.errorHandler(err);
 131         }
 132         else {
 133             throw err;
 134         }
 135    },
 136
 137     // stop activity by clearing tiemouts
 138    stop: function ()
 139    {
 140        clearTimeout(this.statTimer);
 141        clearTimeout(this.showTimer);
 142        clearTimeout(this.termTimer);
 143        clearTimeout(this.bytargetTimer);
 144     },
 145
 146     // reset status variables
 147     reset: function ()
 148     {
 149         if ( this.useSessions ) {
 150             this.sessionID = null;
 151             this.initStatusOK = false;
 152             this.pingStatusOK = false;
 153         }
 154         this.searchStatusOK = false;
 155         this.stop();
 156
 157         if ( this.resetCallback )
 158                 this.resetCallback();
 159     },
 160
 161     init: function ( sessionId )
 162     {
 163         this.reset();
 164
 165         // session id as a param
 166         if ( sessionId != undefined && this.useSessions ) {
 167             this.initStatusOK = true;
 168             this.sessionID = sessionId;
 169             this.ping();
 170         // old school direct pazpar2 init
 171         } else if (this.useSessions) {
 172             var context = this;
 173             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 174             request.get(
 175                 { "command": "init" },
 176                 function(data) {
 177                     if ( data.getElementsByTagName("status")[0]
 178                             .childNodes[0].nodeValue == "OK" ) {
 179                         if ( data.getElementsByTagName("protocol")[0]
 180                                 .childNodes[0].nodeValue
 181                             != context.suppProtoVer )
 182                             throw new Error(
 183                                 "Server's protocol not supported by the client"
 184                             );
 185                         context.initStatusOK = true;
 186                         context.sessionID =
 187                             data.getElementsByTagName("session")[0]
 188                                 .childNodes[0].nodeValue;
 189                         setTimeout(
 190                             function () {
 191                                 context.ping();
 192                             },
 193                             context.keepAlive
 194                         );
 195                         if ( context.initCallback )
 196                             context.initCallback();
 197                     }
 198                     else
 199                         context.throwError('Init failed. Malformed WS resonse.',
 200                                             110);
 201                 }
 202             );
 203         // when through proxy no need to init
 204         } else {
 205             this.initStatusOK = true;
 206         }
 207     },
 208     // no need to ping explicitly
 209     ping: function ()
 210     {
 211         // pinging only makes sense when using pazpar2 directly
 212         if( !this.initStatusOK || !this.useSessions )
 213             throw new Error(
 214             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 215             );
 216         var context = this;
 217         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 218         request.get(
 219             { "command": "ping", "session": this.sessionID },
 220             function(data) {
 221                 if ( data.getElementsByTagName("status")[0]
 222                         .childNodes[0].nodeValue == "OK" ) {
 223                     context.pingStatusOK = true;
 224                     setTimeout(
 225                         function () {
 226                             context.ping();
 227                         },
 228                         context.keepAlive
 229                     );
 230                 }
 231                 else
 232                     context.throwError('Ping failed. Malformed WS resonse.',
 233                                         111);
 234             }
 235         );
 236     },
 237     search: function (query, num, sort, filter, showfrom)
 238     {
 239         clearTimeout(this.statTimer);
 240         clearTimeout(this.showTimer);
 241         clearTimeout(this.termTimer);
 242         clearTimeout(this.bytargetTimer);
 243
 244         this.showCounter = 0;
 245         this.termCounter = 0;
 246         this.bytargetCounter = 0;
 247         this.statCounter = 0;
 248
 249         // no proxy mode
 250         if( !this.initStatusOK )
 251             throw new Error('Pz2.js: session not initialized.');
 252
 253         if( query !== undefined )
 254             this.currQuery = query;
 255         else
 256             throw new Error("Pz2.js: no query supplied to the search command.");
 257
 258         if ( showfrom !== undefined )
 259             var start = showfrom;
 260         else
 261             var start = 0;
 262
 263         var searchParams = {
 264             "command": "search",
 265             "query": this.currQuery,
 266             "session": this.sessionID
 267         };
 268
 269         if (filter !== undefined)
 270             searchParams["filter"] = filter;
 271
 272         var context = this;
 273         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 274         request.get(
 275             searchParams,
 276             function(data) {
 277                 if ( data.getElementsByTagName("status")[0]
 278                         .childNodes[0].nodeValue == "OK" ) {
 279                     context.searchStatusOK = true;
 280                     //piggyback search
 281                     context.show(start, num, sort);
 282                     if ( context.statCallback )
 283                         context.stat();
 284                     if ( context.termlistCallback )
 285                         context.termlist();
 286                     if ( context.bytargetCallback )
 287                         context.bytarget();
 288                 }
 289                 else
 290                     context.throwError('Search failed. Malformed WS resonse.',
 291                                         112);
 292             }
 293         );
 294     },
 295     stat: function()
 296     {
 297         if( !this.initStatusOK )
 298             throw new Error('Pz2.js: session not initialized.');
 299
 300         // if called explicitly takes precedence
 301         clearTimeout(this.statTimer);
 302
 303         var context = this;
 304         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 305         request.get(
 306             { "command": "stat", "session": this.sessionID },
 307             function(data) {
 308                 if ( data.getElementsByTagName("stat") ) {
 309                     var activeClients =
 310                         Number( data.getElementsByTagName("activeclients")[0]
 311                                     .childNodes[0].nodeValue );
 312                     context.activeClients = activeClients;
 313                     var stat = {
 314                         "activeclients": activeClients,
 315                         "hits":
 316                             Number( data.getElementsByTagName("hits")[0]
 317                                         .childNodes[0].nodeValue ),
 318                         "records":
 319                             Number( data.getElementsByTagName("records")[0]
 320                                         .childNodes[0].nodeValue ),
 321                         "clients":
 322                             Number( data.getElementsByTagName("clients")[0]
 323                                         .childNodes[0].nodeValue ),
 324                         "initializing":
 325                             Number( data.getElementsByTagName("initializing")[0]
 326                                         .childNodes[0].nodeValue ),
 327                         "searching":
 328                             Number( data.getElementsByTagName("searching")[0]
 329                                         .childNodes[0].nodeValue ),
 330                         "presenting":
 331                             Number( data.getElementsByTagName("presenting")[0]
 332                                         .childNodes[0].nodeValue ),
 333                         "idle":
 334                             Number( data.getElementsByTagName("idle")[0]
 335                                         .childNodes[0].nodeValue ),
 336                         "failed":
 337                             Number( data.getElementsByTagName("failed")[0]
 338                                         .childNodes[0].nodeValue ),
 339                         "error":
 340                             Number( data.getElementsByTagName("error")[0]
 341                                         .childNodes[0].nodeValue )
 342                     };
 343
 344                     context.statCounter++;
 345                     var delay = context.statTime
 346                         + context.statCounter * context.dumpFactor;
 347
 348                     if ( activeClients > 0 )
 349                         context.statTimer =
 350                             setTimeout(
 351                                 function () {
 352                                     context.stat();
 353                                 },
 354                                 delay
 355                             );
 356                     context.statCallback(stat);
 357                 }
 358                 else
 359                     context.throwError('Stat failed. Malformed WS resonse.',
 360                                         113);
 361             }
 362         );
 363     },
 364     show: function(start, num, sort)
 365     {
 366         if( !this.searchStatusOK && this.useSessions )
 367             throw new Error(
 368                 'Pz2.js: show command has to be preceded with a search command.'
 369             );
 370
 371         // if called explicitly takes precedence
 372         clearTimeout(this.showTimer);
 373
 374         if( sort !== undefined )
 375             this.currentSort = sort;
 376         if( start !== undefined )
 377             this.currentStart = Number( start );
 378         if( num !== undefined )
 379             this.currentNum = Number( num );
 380
 381         var context = this;
 382         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 383         request.get(
 384             {
 385                 "command": "show",
 386                 "session": this.sessionID,
 387                 "start": this.currentStart,
 388                 "num": this.currentNum,
 389                 "sort": this.currentSort,
 390                 "block": 1
 391             },
 392             function(data) {
 393                 if ( data.getElementsByTagName("status")[0]
 394                         .childNodes[0].nodeValue == "OK" ) {
 395                     // first parse the status data send along with records
 396                     // this is strictly bound to the format
 397                     var activeClients =
 398                         Number( data.getElementsByTagName("activeclients")[0]
 399                                     .childNodes[0].nodeValue );
 400                     context.activeClients = activeClients;
 401                     var show = {
 402                         "activeclients": activeClients,
 403                         "merged":
 404                             Number( data.getElementsByTagName("merged")[0]
 405                                         .childNodes[0].nodeValue ),
 406                         "total":
 407                             Number( data.getElementsByTagName("total")[0]
 408                                         .childNodes[0].nodeValue ),
 409                         "start":
 410                             Number( data.getElementsByTagName("start")[0]
 411                                         .childNodes[0].nodeValue ),
 412                         "num":
 413                             Number( data.getElementsByTagName("num")[0]
 414                                         .childNodes[0].nodeValue ),
 415                         "hits": []
 416                     };
 417                     // parse all the first-level nodes for all <hit> tags
 418                     var hits = data.getElementsByTagName("hit");
 419                     var hit = new Array();
 420                     for (i = 0; i < hits.length; i++) {
 421                         show.hits[i] = new Array();
 422                         show.hits[i]['location'] = new Array();
 423                         var locCount = 0;
 424                         for ( j = 0; j < hits[i].childNodes.length; j++) {
 425                             if ( hits[i].childNodes[j].nodeType
 426                                 == Node.ELEMENT_NODE ) {
 427                                 if (hits[i].childNodes[j].nodeName
 428                                     == 'location') {
 429                                     var locNode = hits[i].childNodes[j];
 430                                     var id = locNode.getAttribute('id');
 431                                     show.hits[i]['location'][locCount] = {
 432                                         "id": locNode.getAttribute("id"),
 433                                         "name": locNode.getAttribute("name")
 434                                     };
 435                                     locCount++;
 436                                 }
 437                                 else {
 438                                     var nodeName =
 439                                         hits[i].childNodes[j].nodeName;
 440                                     var nodeText = 'ERROR'
 441                                     if ( hits[i].childNodes[j].firstChild )
 442                                         nodeText =
 443                                             hits[i].childNodes[j]
 444                                                 .firstChild.nodeValue;
 445                                     show.hits[i][nodeName] = nodeText;
 446                                 }
 447                             }
 448                         }
 449                     }
 450                     context.showCounter++;
 451                     var delay = context.showTime;
 452                     if (context.showCounter > context.showFastCount)
 453                             delay += context.showCounter * context.dumpFactor;
 454                     if ( activeClients > 0 )
 455                         context.showTimer = setTimeout(
 456                             function () {
 457                                 context.show();
 458                             },
 459                             delay);
 460
 461                     context.showCallback(show);
 462                 }
 463                 else
 464                     context.throwError('Show failed. Malformed WS resonse.',
 465                                         114);
 466             }
 467         );
 468     },
 469     record: function(id, offset, pass_params)
 470     {
 471         // we may call record with no previous search if in proxy mode
 472         if( !this.searchStatusOK && this.useSessions)
 473            throw new Error(
 474             'Pz2.js: record command has to be preceded with a search command.'
 475             );
 476         var params = {};
 477         if ( pass_params != undefined )
 478             params = pass_params;
 479
 480         var callback;
 481         if ( params.callback != undefined ) {
 482             callback = params.callback;
 483         } else {
 484             callback = this.recordCallback;
 485         }
 486
 487         var handle;
 488         if ( params['handle'] == undefined )
 489             handle = {};
 490         else
 491             handle = params['handle'];
 492
 493         if( id !== undefined )
 494             this.currRecID = id;
 495
 496         var context = this;
 497         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 498
 499         var recordParams = { "command": "record",
 500                             "session": this.sessionID,
 501                             "id": this.currRecID };
 502
 503         if (offset !== undefined) {
 504             recordParams["offset"] = offset;
 505         }
 506
 507         if (params.syntax != undefined) {
 508             recordParams['syntax'] = params.syntax;
 509         }
 510
 511         this.currRecOffset = offset;
 512
 513         request.get(
 514             recordParams,
 515             function(data) {
 516                 var recordNode;
 517                 var record = new Array();
 518                 record['xmlDoc'] = data;
 519                 if (context.currRecOffset !== undefined) {
 520                     record['offset'] = context.currRecOffset;
 521                     callback(record, handle);
 522                 } else if ( recordNode =
 523                     data.getElementsByTagName("record")[0] ) {
 524                     // if stylesheet was fetched do not parse the response
 525                     if ( context.xslDoc ) {
 526                         record['recid'] =
 527                             recordNode.getElementsByTagName("recid")[0]
 528                                 .firstChild.nodeValue;
 529                         record['xslDoc'] =
 530                             context.xslDoc;
 531                     } else {
 532                         for ( i = 0; i < recordNode.childNodes.length; i++) {
 533                             if ( recordNode.childNodes[i].nodeType
 534                                 == Node.ELEMENT_NODE
 535                                 && recordNode.childNodes[i].nodeName
 536                                 != 'location' ) {
 537                                 var nodeName =
 538                                     recordNode.childNodes[i].nodeName;
 539                                 var nodeText = '';
 540                                 if (recordNode.childNodes[i].firstChild)
 541                                     nodeText = recordNode.childNodes[i]
 542                                         .firstChild.nodeValue;
 543                                 record[nodeName] = nodeText;
 544                             }
 545                         }
 546                         // the location might be empty!!
 547                         var locationNodes =
 548                             recordNode.getElementsByTagName("location");
 549                         record["location"] = new Array();
 550                         for ( i = 0; i < locationNodes.length; i++ ) {
 551                             record["location"][i] = {
 552                                 "id": locationNodes[i].getAttribute("id"),
 553                                 "name": locationNodes[i].getAttribute("name")
 554                             };
 555
 556                             for (j = 0;
 557                                 j < locationNodes[i].childNodes.length;
 558                                 j++) {
 559                                 if ( locationNodes[i].childNodes[j].nodeType
 560                                     == Node.ELEMENT_NODE ) {
 561                                     var nodeName =
 562                                         locationNodes[i].childNodes[j].nodeName;
 563                                     var nodeText = '';
 564                                     if (locationNodes[i].childNodes[j]
 565                                             .firstChild)
 566                                         nodeText =
 567                                             locationNodes[i].childNodes[j]
 568                                                 .firstChild.nodeValue;
 569                                     // this is stupid
 570                                     if (nodeName == 'md-subject') {
 571                                         if (record["location"][i][nodeName]) {
 572                                             record["location"][i][nodeName]
 573                                                 .push(nodeText)
 574                                         } else {
 575                                             record["location"][i][nodeName]
 576                                                 = new Array();
 577                                             record["location"][i][nodeName]
 578                                                 .push(nodeText)
 579                                         }
 580                                     } else {
 581                                         record["location"][i][nodeName]
 582                                             = nodeText;
 583                                     }
 584                                 }
 585                             }
 586                         }
 587                     }
 588
 589                     callback(record, handle);
 590                 }
 591                 else
 592                     context.throwError('Record failed. Malformed WS resonse.',
 593                                         115);
 594             }
 595         );
 596     },
 597
 598     termlist: function()
 599     {
 600         if( !this.searchStatusOK && this.useSessions )
 601             throw new Error(
 602             'Pz2.js: termlist command has to be preceded with a search command.'
 603             );
 604
 605         // if called explicitly takes precedence
 606         clearTimeout(this.termTimer);
 607
 608         var context = this;
 609         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 610         request.get(
 611             {
 612                 "command": "termlist",
 613                 "session": this.sessionID,
 614                 "name": this.termKeys
 615             },
 616             function(data) {
 617                 if ( data.getElementsByTagName("termlist") ) {
 618                     var activeClients =
 619                         Number( data.getElementsByTagName("activeclients")[0]
 620                                     .childNodes[0].nodeValue );
 621                     context.activeClients = activeClients;
 622                     var termList = { "activeclients":  activeClients };
 623                     var termLists = data.getElementsByTagName("list");
 624                     //for each termlist
 625                     for (i = 0; i < termLists.length; i++) {
 626                         var listName = termLists[i].getAttribute('name');
 627                         termList[listName] = new Array();
 628                         var terms = termLists[i].getElementsByTagName('term');
 629                         //for each term in the list
 630                         for (j = 0; j < terms.length; j++) {
 631                             var term = {
 632                                 "name":
 633                                     (terms[j].getElementsByTagName("name")[0]
 634                                         .childNodes.length
 635                                     ? terms[j].getElementsByTagName("name")[0]
 636                                         .childNodes[0].nodeValue
 637                                     : 'ERROR'),
 638                                 "freq":
 639                                     terms[j]
 640                                     .getElementsByTagName("frequency")[0]
 641                                     .childNodes[0].nodeValue || 'ERROR'
 642                             };
 643
 644                             var termIdNode =
 645                                 terms[j].getElementsByTagName("id");
 646                             if(terms[j].getElementsByTagName("id").length)
 647                                 term["id"] =
 648                                     termIdNode[0].childNodes[0].nodeValue;
 649                             termList[listName][j] = term;
 650                         }
 651                     }
 652
 653                     context.termCounter++;
 654                     var delay = context.termTime
 655                         + context.termCounter * context.dumpFactor;
 656                     if ( activeClients > 0 )
 657                         context.termTimer =
 658                             setTimeout(
 659                                 function () {
 660                                     context.termlist();
 661                                 },
 662                                 delay
 663                             );
 664
 665                    context.termlistCallback(termList);
 666                 }
 667                 else
 668                     context.throwError('Termlist failed. Malformed WS resonse.',
 669                                         116);
 670             }
 671         );
 672
 673     },
 674     bytarget: function()
 675     {
 676         if( !this.initStatusOK && this.useSessions )
 677             throw new Error(
 678             'Pz2.js: bytarget command has to be preceded with a search command.'
 679             );
 680
 681         // no need to continue
 682         if( !this.searchStatusOK )
 683             return;
 684
 685         // if called explicitly takes precedence
 686         clearTimeout(this.bytargetTimer);
 687
 688         var context = this;
 689         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 690         request.get(
 691             { "command": "bytarget", "session": this.sessionID },
 692             function(data) {
 693                 if ( data.getElementsByTagName("status")[0]
 694                         .childNodes[0].nodeValue == "OK" ) {
 695                     var targetNodes = data.getElementsByTagName("target");
 696                     var bytarget = new Array();
 697                     for ( i = 0; i < targetNodes.length; i++) {
 698                         bytarget[i] = new Array();
 699                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 700                             if ( targetNodes[i].childNodes[j].nodeType
 701                                 == Node.ELEMENT_NODE ) {
 702                                 var nodeName =
 703                                     targetNodes[i].childNodes[j].nodeName;
 704                                 var nodeText =
 705                                     targetNodes[i].childNodes[j]
 706                                         .firstChild.nodeValue;
 707                                 bytarget[i][nodeName] = nodeText;
 708                             }
 709                         }
 710                     }
 711
 712                     context.bytargetCounter++;
 713                     var delay = context.bytargetTime
 714                         + context.bytargetCounter * context.dumpFactor;
 715                     if ( context.activeClients > 0 )
 716                         context.bytargetTimer =
 717                             setTimeout(
 718                                 function () {
 719                                     context.bytarget();
 720                                 },
 721                                 delay
 722                             );
 723
 724                     context.bytargetCallback(bytarget);
 725                 }
 726                 else
 727                     context.throwError('Bytarget failed. Malformed WS resonse.',
 728                                         117);
 729             }
 730         );
 731     },
 732
 733     // just for testing, probably shouldn't be here
 734     showNext: function(page)
 735     {
 736         var step = page || 1;
 737         this.show( ( step * this.currentNum ) + this.currentStart );
 738     },
 739
 740     showPrev: function(page)
 741     {
 742         if (this.currentStart == 0 )
 743             return false;
 744         var step = page || 1;
 745         var newStart = this.currentStart - (step * this.currentNum );
 746         this.show( newStart > 0 ? newStart : 0 );
 747     },
 748
 749     showPage: function(pageNum)
 750     {
 751         //var page = pageNum || 1;
 752         this.show(pageNum * this.currentNum);
 753     }
 754 };
 755
 756 /*
 757 ********************************************************************************
 758 ** AJAX HELPER CLASS ***********************************************************
 759 ********************************************************************************
 760 */
 761 var pzHttpRequest = function ( url, errorHandler ) {
 762         this.request = null;
 763         this.url = url;
 764         this.errorHandler = errorHandler || null;
 765         this.async = true;
 766
 767         if ( window.XMLHttpRequest ) {
 768             this.request = new XMLHttpRequest();
 769         } else if ( window.ActiveXObject ) {
 770             try {
 771                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 772             } catch (err) {
 773                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 774             }
 775         }
 776 };
 777
 778 pzHttpRequest.prototype =
 779 {
 780     get: function ( params, callback )
 781     {
 782         this._send( 'GET', params, '', callback );
 783     },
 784
 785     post: function ( params, data, callback )
 786     {
 787         this._send( 'POST', params, data, callback );
 788     },
 789
 790     load: function ()
 791     {
 792         this.async = false;
 793         this.request.open( 'GET', this.url, this.async );
 794         this.request.send('');
 795         if ( this.request.status == 200 )
 796             return this.request.responseXML;
 797     },
 798
 799     _send: function ( type, params, data, callback )
 800     {
 801         this.callback = callback;
 802         var context = this;
 803         this.async = true;
 804         this.request.open( type, this._urlAppendParams(params), this.async );
 805         this.request.onreadystatechange = function () {
 806             context._handleResponse();
 807         }
 808         this.request.send(data);
 809     },
 810
 811     _urlAppendParams: function (params)
 812     {
 813         var getUrl = this.url;
 814
 815         var sep = '?';
 816         var el = params;
 817         for (var key in el) {
 818             if (el[key] != null) {
 819                 getUrl += sep + key + '=' + encodeURIComponent(el[key]);
 820                 sep = '&';
 821             }
 822         }
 823         return getUrl;
 824     },
 825
 826     _handleResponse: function ()
 827     {
 828         if ( this.request.readyState == 4 ) {
 829             // pick up pazpr2 errors first
 830             if ( this.request.responseXML
 831                 && this.request.responseXML.documentElement.nodeName == 'error'
 832                 && this.request.responseXML.getElementsByTagName("error")
 833                     .length ) {
 834                 var errAddInfo = '';
 835                 if ( this.request.responseXML.getElementsByTagName("error")[0]
 836                         .childNodes.length )
 837                     errAddInfo = ': ' +
 838                         this.request.responseXML
 839                             .getElementsByTagName("error")[0]
 840                             .childNodes[0].nodeValue;
 841                 var errMsg =
 842                     this.request.responseXML.getElementsByTagName("error")[0]
 843                         .getAttribute("msg");
 844                 var errCode =
 845                     this.request.responseXML.getElementsByTagName("error")[0]
 846                         .getAttribute("code");
 847
 848                 var err = new Error(errMsg + errAddInfo);
 849                 err.code = errCode;
 850
 851                 if (this.errorHandler) {
 852                     this.errorHandler(err);
 853                 }
 854                 else {
 855                     throw err;
 856                 }
 857             } else if ( this.request.status == 200 ) {
 858                 this.callback( this.request.responseXML );
 859             } else {
 860                 var err = new Error("Pz2.js: HTTP request error (AJAX). Code: "
 861                             + this.request.status + " Info: "
 862                             + this.request.statusText );
 863                 err.code = 'HTTP';
 864
 865                 if (this.errorHandler) {
 866                     this.errorHandler(err);
 867                 }
 868                 else {
 869                     throw err;
 870                 }
 871             }
 872         }
 873     }
 874 };
 875
 876 /*
 877 ********************************************************************************
 878 ** XML HELPER FUNCTIONS ********************************************************
 879 ********************************************************************************
 880 */
 881
 882 // DOMDocument
 883
 884 if ( window.ActiveXObject) {
 885     var DOMDoc = document;
 886 } else {
 887     var DOMDoc = Document.prototype;
 888 }
 889
 890 DOMDoc.newXmlDoc = function ( root )
 891 {
 892     var doc;
 893
 894     if (document.implementation && document.implementation.createDocument) {
 895         doc = document.implementation.createDocument('', root, null);
 896     } else if ( window.ActiveXObject ) {
 897         doc = new ActiveXObject("MSXML2.DOMDocument");
 898         doc.loadXML('<' + root + '/>');
 899     } else {
 900         throw new Error ('No XML support in this browser');
 901     }
 902
 903     return doc;
 904 }
 905
 906
 907 DOMDoc.parseXmlFromString = function ( xmlString )
 908 {
 909     var doc;
 910
 911     if ( window.DOMParser ) {
 912         var parser = new DOMParser();
 913         doc = parser.parseFromString( xmlString, "text/xml");
 914     } else if ( window.ActiveXObject ) {
 915         doc = new ActiveXObject("MSXML2.DOMDocument");
 916         doc.loadXML( xmlString );
 917     } else {
 918         throw new Error ("No XML parsing support in this browser.");
 919     }
 920
 921     return doc;
 922 }
 923
 924 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 925 {
 926     if ( window.XSLTProcessor ) {
 927         var proc = new XSLTProcessor();
 928         proc.importStylesheet( xslDoc );
 929         return proc.transformToDocument(xmlDoc);
 930     } else if ( window.ActiveXObject ) {
 931         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 932     } else {
 933         alert( 'Unable to perform XSLT transformation in this browser' );
 934     }
 935 }
 936
 937 // DOMElement
 938
 939 Element_removeFromDoc = function (DOM_Element)
 940 {
 941     DOM_Element.parentNode.removeChild(DOM_Element);
 942 }
 943
 944 Element_emptyChildren = function (DOM_Element)
 945 {
 946     while( DOM_Element.firstChild ) {
 947         DOM_Element.removeChild( DOM_Element.firstChild )
 948     }
 949 }
 950
 951 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 952 {
 953     if ( window.XSLTProcessor ) {
 954         var proc = new XSLTProcessor();
 955         proc.importStylesheet( xslDoc );
 956         var docFrag = false;
 957         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 958         DOM_Element.appendChild(docFrag);
 959     } else if ( window.ActiveXObject ) {
 960         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 961     } else {
 962         alert( 'Unable to perform XSLT transformation in this browser' );
 963     }
 964 }
 965
 966 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 967 {
 968     var node = DOM_Element.ownerDocument.createElement(tagName);
 969     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 970
 971     DOM_Element.appendChild(node);
 972     node.appendChild(text);
 973
 974     return node;
 975 }
 976
 977 Element_setTextContent = function ( DOM_Element, textContent )
 978 {
 979     if (typeof DOM_Element.textContent !== "undefined") {
 980         DOM_Element.textContent = textContent;
 981     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 982         DOM_Element.innerText = textContent;
 983     } else {
 984         throw new Error("Cannot set text content of the node, no such method.");
 985     }
 986 }
 987
 988 Element_getTextContent = function (DOM_Element)
 989 {
 990     if ( typeof DOM_Element.textContent != 'undefined' ) {
 991         return DOM_Element.textContent;
 992     } else if (typeof DOM_Element.text != 'undefined') {
 993         return DOM_Element.text;
 994     } else {
 995         throw new Error("Cannot get text content of the node, no such method.");
 996     }
 997 }
 998
 999 /* do not remove trailing bracket */
1000 }