Elda

Elda is a Java implementation of the Linked Data API by Epimorphics. Elda provides a configurable way to create an API to access RDF data using simple RESTful URLs. These URLs are translated into queries to a SPARQL endpoint. The API developer writes an API spec – in RDF – which specifies how to translate URLs into queries.

Getting Elda

The currently released version of Elda is 2.0.2

• [Download the current version of the standalone demonstration jar] (http://repository.epimorphics.com/com/epimorphics/lda/elda-standalone/2.0.2/elda-standalone-2.0.2-exec-war.jar)
• See the Github repository for the source code
• See below for an example Apache Maven pom.xml snippet

Documentation index

• Quick start
  Some pre-built examples which allow you to experiment with the style of query and get started with building your own configurations.

• Reference
  Comprehensive reference documentation for API developers

• Velocity renderer
  ELda includes a pre-configured, but customizable, renderer for generating HTML pages from RDF resources using Apache Velocity.

• Java API documentation

• Forthcoming
  The in-development documentation, which may give an indication of forthcoming features or changes.

• Links to the documentation for other Elda versions if you are running a non-current version of Elda.

Elda tutorials

• Text search - worked example

Release history

• Elda release 2.0.2

  Elda 2.0.2 was released on September 21st 2021. This release of Elda contains a minor security update.

• Elda release 2.0.1

  Elda 2.0.1 was released on August 1st 2019. This release of Elda contains a minor update to its Tomcat dependencies.

• Elda release 2.0.0

  Elda 2.0.0 was released on September 17th 2018. This release of Elda contains (minor) backwards-incompatible changes, hence the major version update.

• Elda release 1.5.0-RC

  Elda 1.5.0-RC was released on 1st August 2018.

• Elda release 1.4.3

  Elda 1.4.3 was released on 13th October 2017.

• Elda release 1.4.2

  (This release of Elda contains a bug in standalone run from an executable jar. If you use standalone, use 1.4.3 not 1.4.2.)

• Elda release 1.4.0

  Elda 1.4.0 was released on 10th May 2017, with a new query parameter _query-id whose value is displayed in log messages generated for this query.

• Elda release 1.3.25

  Elda 1.3.25 was released on 24th April 2017.

• Elda release 1.3.24

  Elda 1.3.22 was released on 7th March 2017.

• Elda release 1.3.22

  Elda 1.3.22 was released on 1st March 2017.

• Elda release 1.3.19

  Elda 1.3.19 was released on November 4th 2016.

• Elda release 1.3.18

  Elda 1.3.18 was released on June 6th 2016.

• Elda release 1.3.16

  Elda 1.3.16 was released on September 21st 2015. It supersedes 1.3.15.

• Elda release 1.3.15

  Elda 1.3.15 was released on September 18th 2015. It supersedes 1.3.14.

• Elda release 1.3.14

  Elda 1.3.14 was released on July 23rd 2015. It supersedes 1.3.13.

• Elda release 1.3.13

  Elda 1.3.13 was released on May 22th 2015. It supersedes 1.3.12.

• Elda release 1.3.12

  Elda 1.3.12 was released on May 22th 2015. It supersedes all of .9 – .11.

• Elda release 1.3.11

  Elda 1.3.11 was released on May 19th 2015.

• Elda release 1.3.10

  [Elda 1.3.10 was created on 18th May 2015 but a defect in the release process meant that only a 1.3.10-SNAPSHOT was created. Use 1.3.12 instead.]

• Elda release 1.3.9

  [There is no Elda release 1.3.6, .7, .8, for technical reasons.]

• Elda release 1.3.4

  Elda 1.3.4 was released on 15th January 2015. Support for SPARQL 1.0, elda-bundled, and elda-system-tests has been dropped. The error-page rendering has been improved.

• Elda release 1.3.3

  Elda 1.3.3 was released on 12th January 2015 and corrected a mistake in Elda’s version identification string.

• Elda release 1.3.2

  Elda 1.3.2 was released on 12th January 2015 and contained fixes for issues #111 and #112. Due to a minor defect in its version identification, it was immediately superceded by Elda 1.3.3.

• Elda release 1.3.1

  Elda 1.3.1 was released on 27th November 2014 (groupid com.epimorphics.lda, artifactId and name lda, version 1.3.1), with some changes to the error-reporting behaviour.

• Elda release 1.3.0

  Elda 1.3.0 was released on 12th November 2014 (groupid com.epimorphics.lda, artifactId and name lda, version 1.3.0), with a rewritten Velocity renderer.

• Elda release 1.2.35

  Elda 1.2.35 was released on 30th July 2014 (groupid com.epimorphics.lda, artifactId and name lda, version 1.2.35). i

• Elda release 1.2.34

  Elda 1.2.34 was released on 8th July 2014 (groupid com.epimorphics.lda, artifactId and name lda, version 1.2.33). The default XSLT processer has been changed to Saxon 9.5.1-5. The mapping from strings to resource names for XSLT tenplates and the Velocity root has been made the same and is more precisely defined. It is now possible to specify on an endpoint or in a request URI the name of a non-default graph in the SPARQL endpoint’s dataset.

• Elda release 1.2.33

  Elda 1.2.33 was released on 23rd April 2014 (groupid com.epimorphics.lda, artifactId and name lda, version 1.2.33). It corrects a problem with item endpoints which failed to find the requested item but did not generate a 404 response status. (Version .32 was an intermediate release that incompletely resolved this issue.)

• Elda release 1.2.31

  Elda 1.2.31 (ReleaseNotes/latest.text) was released on 24th March 2014. Elda now allows cache expiry times to be attached to properties, endpoints, and APIs, generates Expires: headers appropriately, and respects those expiry times in its internal caches.

Example Maven configuration

  <?xml version="1.0" encoding="UTF-8"?>
  <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <build>
    </build>
    <dependencies>
      <dependency>
        <groupId>com.epimorphics.lda</groupId>
        <artifactId>elda-lda</artifactId>
        <version>2.0.2</version>
      </dependency>
      <dependency>
        <groupId>com.epimorphics.lda</groupId>
        <artifactId>elda-assets</artifactId>
        <version>2.0.2</version>
        <type>war</type>
      </dependency>
    </dependencies>
    <repositories>
      <repository>
        <id>epi-public-repo</id>
        <name>Epimorphics Public Repository</name>
        <url>http://repository.epimorphics.com</url>
        <layout>default</layout>
        <releases>
          <enabled>true</enabled>
        </releases>
        <snapshots>
          <enabled>true</enabled>
        </snapshots>
      </repository>
    </repositories>
  </project>