Text Class Collection Implementation

DLXS Workshop, February 2002

Text Class Instructor: Chris Powell

This portion of the DLXS Workshop focuses on implementing a collection in the Text Class. It is organized as a hands-on lesson, with the entire process outlined in detail. All of the steps are included so that it can be repeated or used as a guide later. Links to the detailed Text Class documentation are included.

A printed copy of this document will be available at the workshop.

Workshop Day 2 -- Tuesday Afternoon

Workshop Day 3 -- Wednesday Morning

Workshop Day 3 -- Wednesday Afternoon

Workshop Day 2 -- Tuesday Afternoon

Text Class Content Prep

In Text Class Content Prep we discuss the elements and attributes required for Text Class delivery, the necessary architecture for storing texts and collections, strategies and methods for converting texts to conform to the Text Class DTD, and normalization.

Text Class DTD Overview

It is assumed that any texts to be converted to Text Class already validate against another DTD for encoding monographic materials, such as TEI Lite, that represents corresponding structures (chapters, pages, etc.). Because of the extremely lax content modelling (almost every element is defined to permit ANY of the named elements), the Text Class DTD is only useful to ensure that the nomenclatures have been changed appropriately.

The following elements and attributes are required:

The Text Class DTD is a fluid document; more attributes, and occassionally elements, are added as the need arises in processing new collections. These basic requirements are unlikely to change, however.

Text Conversion Strategies

DLPS does not have any preferred methods or quick and easy tools for this stage of the process. Only you, looking at your texts and your encoding practices, can do the intellectual work required to convert the texts. You should do this with the tools you are most comfortable using, whether they be macros in your favorite editor, perl scripts if you have strong programming skills, OmniMark if you like that, or XSLT (my personal choice). We have a fairly detailed XSLT strategy on the documentation website, which uses freely-available or ubiquitous tools, and if you are creating XML documents anyway, this might be a reasonable route to pursue.

We have also used a perl script to do conversions of TEI Lite-encoded SGML into Text Class SGML, and are willing to make these (largely undocumented) scripts available. We are happy to offer suggestions and our historical experience in converting collections, but cannot really support you with specific tools or methods in your conversion, as it is particular to the encoding of your texts.

For today, we are going to be working with some texts that are already in Text Class, and one file that is in a DTD based on TEI Lite. We will be building them into a collection we are going to call workshoptc.

This documentation will make use of the concept of the $DLXSROOT, which is the place at which your DLXS directory structure starts. We generally use /l1/, but for the workshop, we each have our own $DLXSROOT in the form of /l1/workshop/userX. To determine what your $DLXSROOT is, type the following commands at the command prompt:


Create directory $DLXSROOT/prep/w/workshoptc with the following command:

mkdir -p $DLXSROOT/prep/w/workshoptc/data

Move into that directory with the following command:

cd $DLXSROOT/prep/w/workshoptc/data

This will be your staging area for all the things you will be doing to your texts, and ultimately to your collection. At present, all it contains is the data subdirectory you created a moment ago. We will be populating it further over the course of the next two days. Unlike the contents of other directories, everything in prep should be ultimately expendable in the production environment.

Copy the necessary files into your data directory with the following commands:

cp $DLXSROOT/obj/b/a/b/bab3633.0001.001/bab3633.0001.001.sgm $DLXSROOT/prep/w/workshoptc/data
cp $DLXSROOT/obj/a/a/s/aas7611.0001.001/aas7611.0001.001.sgm $DLXSROOT/prep/w/workshoptc/data
cp $DLXSROOT/obj/a/b/e/abe5413.0001.001/abe5413.0001.001.sgm $DLXSROOT/prep/w/workshoptc/data
cp $DLXSROOT/obj/a/b/u/abu0246.0001.001/abu0246.0001.001.sgm $DLXSROOT/prep/w/workshoptc/data
cp $DLXSROOT/obj/a/f/g/afg3177.0001.001/afg3177.0001.001.sgm $DLXSROOT/prep/w/workshoptc/data

The first file, bab3633.0001.001.sgm, is not yet in the Text Class DTD. However, since it is a very simple text, a few changes will make it so:

We'll also change the N attribute value in the EDITORIALDECL to 4, as it is pretty fully encoded for its size. If you feel confident in your file editing skills in the unix environment, you can do so now (don't forget the end tags!). Otherwise, copy the following script and use it to change your file (this is just for this file -- for real document conversion, see Converting Documents to Text Class below):

$DLXSROOT/prep/s/sampletc/tagfixer.pl  $DLXSROOT/prep/w/workshoptc/data/bab3633.0001.001.sgm

Other Text Modifications

You need to decide whether you wish to keep character entities (for example, é) in your text files or replace them with their 8-bit ISO Latin 1 equivalent (for example, é). If you choose to do this, you will be able to search for blessed, for example, and retrieve both blesséd and blessed, because the indexing process maps both of these characters to just e. Otherwise, you would have to search for blesséd to retrieve the word with the diacritic. If you want to do this (and this process is not necessarily valid for XML, only SGML!), use the following command:

$DLXSROOT/bin/t/text/isolat128bit.pl $DLXSROOT/prep/w/workshoptc/data/bab3633.0001.001.sgm

One way to help the cgi with identifying specific text structures, like divisions, exactly is to insert unique attributes based on a combination of the IDNO and the sequence of the division in the text. This is an expendable ID and not meant to permanently identify a structure -- use you own throughtfully assigned and permanent ID attributes for that. Before indexing, check to see if node attributes have been applied when the documents were converted to Text Class -- they will appear in the DIV tags for each division and will look like this: <DIV1 NODE="AAN8938.0001.001:1">. If they have not, use the following command to insert them:

$DLXSROOT/bin/t/text/nodefy $DLXSROOT/prep/w/workshoptc/data/bab3633.0001.001.sgm
cp $DLXSROOT/prep/w/workshoptc/data/bab3633.0001.001.sgm.noded $DLXSROOT/prep/w/workshoptc/data/bab3633.0001.001.sgm

Validate and Normalize SGML

This step checks the SGML against the Text Class DTD to validate the SGML. It also normalizes the SGML, which, if necessary, adjusts the SGML tagging so that it is consistent in terms of case and order of element attributes.

There are not likely to be any errors with the workshoptc data, but tell the instructor if there are.

foreach file (*.sgm)
sgmlnorm $DLXSROOT/prep/s/sampletc/sampletc.text.inp $file > $file.norm

This will normalize the texts and result in new texts with a .norm extension added. These are the files we will use to build our new collection tomorrow morning.

Storing Texts and Page Images

As you may have noticed from our file copying steps earlier, we store each digitized text in its own directory, based on its DLPS ID, along with the related page images. The DLPS ID is a unique ID for each text, based on the ID assigned to its MARC record by the OPAC. Directories are created in the form $DLXSROOT/obj/d/l/p/dlpsid (the DLPS ID can consist of a mix of number and letter characters). Pageviewer defaults to search for page images stored in a directory based on this form, although there is a method that can be overriden.

To facilitate links between the texts and the images stored in the $DLXSROOT/obj directories, the middleware is configured to read a four-million row table on our MySQL server containing page image metadata. In $DLXSROOT/misc/bb there's a file called Pageview that is a CSV version of that table that continas only the rows for the pages in the sample collection. We are not using this during the workshop. During DLXS installation yesterday, Alan and Phil could have chosen CSV as the database format, and you can always look at this table as an example of necessary metadata fields. However, we have found that CSV does not scale, and while it is feasible for the fewer than 2000 pages in the sample collection, it was not adequate in our production environment. The most recent release of the DLXS middleware does not support pageview.dat files. If you have created pageview.dat files in the past and would like to upgrade to the new middleware, we are delivering a program ($DLXSROOT/bin/t/text/makepageviewdata.pl) that will convert pageview.dat files into MySQL rows. Invocation is simple (don't do it -- just FYI):

$DLXSROOT/bin/t/text/importpageviewdata.pl [-f] -d "$DLXSROOT/obj"

The -f flag indicates a "full run", i.e., process all files regardless of whether they've changed since the last run (otherwise, there is a timestamp file to determine which files have changed since the last run). Based on what database format you chose during DLXS installation, this process will populate the database with the information from any pageview.dat files it encounters as it runs through the directory you specified recursively.

More Documentation

Workshop Day 3 -- Wednesday Morning

Text Class Index Building with XPat

In this section the workshoptc SGML will be concatenated and indexed with the XPat search engine, preparing it for use with the DLXS middleware.

Set Up Directories and Files for XPat Indexing

Yesterday, we did what we needed to do with our materials "by hand" -- today, we will work with the materials packaged in the sampletc collection and adapt them for use with workshoptc. This should parallel what you'll be doing back at your institutions. First, we need to create the rest of the directories in the workshoptc environment with the following commands:

mkdir -p $DLXSROOT/bin/w/workshoptc
mkdir -p $DLXSROOT/obj/w/workshoptc
mkdir -p $DLXSROOT/idx/w/workshoptc

The bin directory holds and scripts or tools used for the collection specifically; obj holds the "object" or SGML/XML file for the collection, and idx holds the XPat indexes. Now we need to populate the directories. First, change directories into $DLXSROOT/prep/w/workshoptc/data and concatenate the texts into one collection with the following command:

cat bab3633.0001.001.sgm.norm aas7611.0001.001.sgm.norm abe5413.0001.001.sgm.norm abu0246.0001.001.sgm.norm afg3177.0001.001.sgm.norm > $DLXSROOT/obj/w/workshoptc/workshoptc.sgm

Next, we'll copy and edit the necessary files from sampletc to get our workshoptc collection together.

cp $DLXSROOT/bin/s/sampletc/Makefile $DLXSROOT/bin/w/workshoptc/Makefile
cp $DLXSROOT/prep/s/sampletc/charents.frag $DLXSROOT/prep/w/workshoptc
cp $DLXSROOT/prep/s/sampletc/textclass.stripped.dtd $DLXSROOT/prep/w/workshoptc
cp $DLXSROOT/prep/s/sampletc/sampletc.single.blank.dd $DLXSROOT/prep/w/workshoptc/workshoptc.single.blank.dd
cp $DLXSROOT/prep/s/sampletc/sampletc.extra.srch $DLXSROOT/prep/w/workshoptc/workshoptc.extra.srch
cp $DLXSROOT/prep/s/sampletc/sampletc.inp $DLXSROOT/prep/w/workshoptc/workshoptc.inp

Four of these files need to be edited to reflect the new collection name and the paths to your particular directories. This will be true when you use these at your home institution as well, even if you use the same directory architecture as we do, because they will always need to reflect the uniqname of each collection. Failure to change even one file can result in puzzling errors, because the scripts are working, just not necessarily in the directories you are looking at.

If you are comfortable editing in the unix environment, in the Makefile, workshoptc.single.blank.dd, workshoptc.extra.srch, and workshoptc.inp, change all references to /l1/ to your $DLXSROOT value, /s/ to /w/ and sampletc to workshoptc. Otherwise, run the following command:

sh $DLXSROOT/paths

Build the Collection Specific Text Class DTD

Before indexing your collection, you will need to create a collection-specific Text Class DTD. Because the class DTD supports any element having any of the declared attributes (for convenience of DTD creation), indexing "as-is" with XPat will cause your index to be unnecessarily large. This may also cause problems for SGML/XML validation tools. A copy of the textclass.stripped.dtd is included in the sample collection; you can create your own from more recent versions of the Text Class DTD by running the following command: (don't do it -- just FYI)

egrep -i "<\!ELEMENT" textclass.dtd > textclass.stripped.dtd

Next, use the "make dtd" command from the Makefile to determine which attributes are used in your collection and build a custom DTD. Using the "make validate" command will then validate your collection against the new DTD. If the individual texts validated before, they should validate as a concatenated collection now.

cd $DLXSROOT/bin/w/workshoptc
make dtd
make validate

Build the XPat Index

Everything is now set up to build the XPat index. The Makefile in the bin directory contains the commands necessary to build the index, and can be executed easily.

To create an index for use with the Text Class interface, you will need to index the words in the collection, then index the SGML/XML (the structural metadata, if you will), and then finally "fabricate" structures based on a combination of elements (for example, defining what the "main entry" is, without adding a <MAINENTRY> tag around the appropriate <AUTHOR> or <TITLE> element). The following commands can be used to make the index, alone or in combination. We will be using "make singledd," make sgml," and "make post."

make singledd indexes words for texts that have been concatenated into on large file for a collection. This is the recommended process.

make sgml indexes the SGML structure by reading the DTD. Validates as it indexes. Slower than multiregion indexing (see below) for this reason. However, necessary for collections that have nested elements of the same name (for example a P within a NOTE1 within a P).

make multi (multiregion structure indexing) indexes the SGML structure and relies on a "tags file" (included in the sample collection) to know what SGML elements and attributes to index. Rarely used with fully-encoded full-text collections because of the nesting problem mentioned above. If you'd like to try this on your own, index only the new text (bab3433.0001.001.sgm.norm)

make mfsdd (multi-file system indexing) indexes words and structure for each SGML text listed in the data dictionary (dd) individually. Seems like a good idea -- no redundant copies of files! -- but searching is slower than an index built of concatenated files. Also, if any one of the files referenced changes in any way, the entire index fails. We no longer use MFS indexes ourselves for this reason. If you'd like to try this on your own, note that this is pointing to the obj directories for the individual texts, and does not include the fifth file we edited yesterday. You'd want to point to your normalized texts in $DLXSROOT/prep/w/workshoptc/data or rename those and copy them out to their individual $DLXSROOT/obj/x/y/z directories.

make post builds and indexes fabricated regions based on the XPat queries stored in the workshoptc.extra.srch file.

make singledd
cp /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.single.blank.dd /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd
/l/local/xpat/bin/xpatbld -m 12m -D /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd
cp /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.presgml.dd
make sgml
cp /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.presgml.dd /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd
/l/local/xpat/bin/sgmlrgn -m region -o /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc -D /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.inp //l1/workshop/sooty/dlxs/obj/w/workshoptc/workshoptc.sgm
cp /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.prepost.dd
make post
cp /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.prepost.dd /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd
touch /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.init
/l/local/xpat/bin/xpat -q /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd < /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.extra.srch | /l1/workshop/sooty/dlxs/bin/t/text/output.dd.frag.pl /l1/workshop/sooty/dlxs/idx/w/workshoptc/ > /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.extra.dd
/l1/workshop/sooty/dlxs/bin/t/text/inc.extra.dd.pl /l1/workshop/sooty/dlxs/prep/w/workshoptc/workshoptc.extra.dd /l1/workshop/sooty/dlxs/idx/w/workshoptc/workshoptc.dd

Workshop Day 3 -- Wednesday Afternoon

Text Class Collection to Web

These are the final steps in deploying an Text Class collection online. Here the Collection Manager will be used to review the Collection Database entry for workshoptc . The Collection Manager will also be used to check the Group Database. Finally, we need to work with the collection map and the set up the collection's web directory.

Review the Collection Database Entry with CollMgr

Each collection has a record in the collection database that holds collection specific configurations for the middleware. CollMgr (Collection Manager) is a web based interface to the collection database that provides functionality for editing each collection's record. Collections can be checked-out for editing, checked-in for testing, and released to production.A collection database record for workshoptc has already been created and we will edit it. In general, a new collection needs to have a CollMgr record created from scratch before the middleware can be used. Take a look at the record to become familiar with it.


Notice that it thinks it's the sampletc collection. Change references to s/sampletc to w/workshoptc . Since we are not building word wheels, remove the data in that field. Let's change the name as well -- remove the reference to graphic:most-logo3bd3.gif and change it to text:whatever you want to call it.

More Documentation

Review the Groups Database Entry with CollMgr

Another function of CollMgr allows the grouping of collections for cross-collection searching. Any number of collection groups may be created for Text Class. Text Class supports a group with the groupid "all". It is not a requirement that all collections be in this group, though that's the basic idea. Groups are created and modified using CollMgr. For this workshop, the group "all" record has already been edited to include the workshoptc collection. Take a look at the record to become familiar with it.


We won't be doing anythign with groups; I'm sure you will in Image Class.

Make Collection Map

Collection mapper files exist to identify the regions and operators used by the middleware when interacting with the search forms. Each collection will need one, but most collections can use a fairly standard map file, such as the one in the sampletc collection. The map files for all Text Class collections are stored in $DLXSROOT/misc/t/text/maps

Map files take language that is used in the forms and translates it into language for the cgi and for XPat. For example, if you want your users to be able to search within chapters, you would need to add a mapping for how you want it to appear in the search interface (case is important, as is pluralization!), how the cgi variable would be set (usually all caps, and not stepping on an existing variable), and how XPat will identify and retrieve this natively.

The first part of the file is operator mapping, for the form, the cgi, and XPat. The second part is for region mapping, as in the example above. There is an optional third part for collections with metadata applied bibliographically, such as genre categories.

cd $DLXSROOT/misc/t/text/maps
cp sampletc.map workshoptc.map

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Set Up the Collection's Web Directory

Each collection may have a web directory with custom Cascading Style Sheets, interface templates, graphics, and javascript. The default is for a collection to use the web templates at $DLXSROOT/web/t/text. A collection specific web directory may be created, and it is necessary if you have any customization at all. For a minimal collection, you will want three files: index.html, home.tpl, and textclass-specific.css.

mkdir -p $DLXSROOT/web/w/workshoptc
cp $DLXSROOT/web/s/sampletc/index.html $DLXSROOT/web/w/workshoptc/index.html
cp $DLXSROOT/web/s/sampletc/home.tpl $DLXSROOT/web/w/workshoptc/home.tpl
cp $DLXSROOT/web/s/sampletc/testclass-specific.css $DLXSROOT/web/w/workshoptc/textclass-specific.css
or for a more simple set of pages to edit
cp /l1/workshop/test01/dlxs/web/s/sampletc/* $DLXSROOT/web/w/workshoptc

As always, we'll need to change the collection name and paths. You might want to change the look radically, if your HTML skills are up to it.

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Try It Out


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