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Elda 2.0.2 {.not-toc}

An implementation of the linked-data API {.not-toc}

Epimorphics.com

Table of contents {.not-toc}

Text Search Worked Example

This document builds an example text search configuration for Elda, based on a Fuseki snapshot for 1.0.1. It contains live links to localhost:8080, which will only work when you’re running a suitably configured Elda.

Download the standalone jar

Download the latest Elda standalone jar from the Epimorphic’s Maven repository: http://repository.epimorphics.com/com/epimorphics/lda/elda-standalone/2.0.2/elda-standalone-2.0.2.jar. Put it somewhere handy; we’ll call the directory it’s in $STANDALONE and use it to set up an Elda server later on. (If you already have a server that you can configure for Elda, you might choose to use that instead.)

Download Fuseki

Go to fuseki snapshot 1.0.1 and download the distribution zip.

Unzip the distribution in a directory of your choice. cd into the jena-fuseki directory. Export the name of this directory as FUSEKI.

Load example data

Download the example data from Elda’s standalone jar. Copy it into $FUSEKI.

We’re going to use the supplied configuration file config-tdb-text.ttl to steer the load and indexing. This sets up a dataset for holding the example data in a TDB in the directory DB.

in $FUSEKI, run:

java -cp ./fuseki-server.jar tdb.tdbloader --tdb=config-tdb-text.ttl example-data.ttl

The config file is being used to set up the dataset, which is why it’s being supplied to the --tdb command parameter.

Index the data

We can use the same configuration to run the indexer:

again in $FUSEKI, run:

 java -cp ./fuseki-server.jar jena.textindexer --desc=config-tdb-text.ttl

This time the configuration file is supplied to the –desc command parameter. The loader set up the normal dataset; the indexer is setting up the text-searchable dataset.

Start serving the data

Now we can start Fuseki serving the indexed example data:

./fuseki-server --conf=config-tdb-text.ttl

Fuseki will serve the dataset in DB under the dataset name “/ds” on port 3030 (by default).

Now we’ve got Fuseki running, we can point a browser at , and explore the data with SPARQL queries, before going on to use _search in Elda.

Make a suitable LDA configuration

Fetch the example LDA configuration file from the stand-alone jar’s example configurations.

Comment out the line

; api:sparqlEndpoint <local:data/example-data.ttl>

which tells Elda that this configuration reads its data from the webapp-relative file data/example-data.ttl. Comment in the line

# ; api:sparqlEndpoint <http://localhost:3030/ds/query>

which tells Elda to query the local Fuseki we have set up above.

Save this file somewhere suitable; we’ll refer to it as $CONFIG.

Run the standalone jar

In $STANDALONE, run the standalone jar:

java -jar elda.jar -Delda.spec=$CONFIG

which runs Elda on port 8080 using the provided configuration file. (If port 8080 is already in use, you can change Elda’s port using -Djetty.port=yourPortNumber.)

Exercise _search

In your preferred browser, open

    http://localhost:8080/standalone/again/games

to display a list of games. The names of the games are in the example data as objects of rdfs:label, and the config-tdb-text.ttl indexing configuration indexes rdfs:label as the default field. Try searching with

?_search=Age

?_search=Steam

?_search=Industry

?_search=”Steam Industry”

_search=Inventions

_search=Industry

_search=”Industry AND Inventions”

_search=”Industry Inventions”

appended to the games URI above.

Wrapup

You should now be in a position to work with data of your own choosing and to experiment (if necessary) with different query configurations for different Elda endpoints.