prajna.structure.accessor

Class DbpediaAccessor

java.lang.Object

prajna.structure.AbstractDataAccessor<DataRecord,DataRecord>

prajna.structure.accessor.RecordAccessor

prajna.structure.accessor.DbpediaAccessor

All Implemented Interfaces:

DataAccessor<DataRecord,DataRecord>

Direct Known Subclasses:

DbpediaVerifier

public class DbpediaAccessor
extends RecordAccessor

Accessor which uses Dbpedia to retrieve information. This method uses a few pre-constructed SPARQL queries to retrieve information from the Dbpedia RDF store. It parses the information, and assembles the records into DataRecord items, and builds trees, graphs, and grids from the resulting data. It can query groups of objects by RDF type or by the SKOS subject.

Author:

Edward Swing

Constructor Summary

Constructors

Constructor and Description
DbpediaAccessor()

Method Summary

Methods

Modifier and Type	Method and Description
MultiValueMap<java.lang.String>	queryResource(java.lang.String resourceName) Query Dbpedia for a particular resource.
java.util.HashSet<java.lang.String>	queryResource(java.lang.String resourceName, java.lang.String propertyName) Query Dbpedia for a particular resource and property.
protected java.util.Set<DataRecord>	retrieveRecords(DataTemplate template) Retrieve a set of data records for a particular DataTemplate.
void	setInitParameters(java.util.Map<java.lang.String,java.lang.String> parameters) Set any initialization parameters required by this data accessor.
void	setLanguage(java.lang.String language) Set the language used by the accessor.
void	setQuery(java.lang.String query) Set the query used to identify records from Dbpedia.

Methods inherited from class prajna.structure.accessor.RecordAccessor

addFieldHandler, addToGraph, addToTree, createReferenceNode, extendGraph, extendTree, getDataset, getFieldHandler, getGraph, getGrid, getMaxRecords, getReasoner, getStructureReasoners, getTree, setMaxRecords, setReasoner, setReasoner

Methods inherited from class prajna.structure.AbstractDataAccessor

addStructure, addTemplate, getDatasetNames, getGraphNames, getGridNames, getSpec, getStructureType, getTemplate, getTemplateNames, getTreeNames, setConfig, setConfigFile, setConfigFile

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DbpediaAccessor

public DbpediaAccessor()

Method Detail

queryResource

public MultiValueMap<java.lang.String> queryResource(java.lang.String resourceName)

Query Dbpedia for a particular resource. The resource name should include the full dbpedia resource specification for the resource.

Parameters:

resourceName - the resource reference

Returns:

a map containing the properties and values of the reference

queryResource

public java.util.HashSet<java.lang.String> queryResource(java.lang.String resourceName,
                                                java.lang.String propertyName)

Query Dbpedia for a particular resource and property. The resource name and property name should include the full dbpedia resource specification for the resource. The resourceName is the subject, the propertyName is the Predicate. The matching Objects are returned

Parameters:

resourceName - the resource reference - the Subject

propertyName - the property value - the Predicate

Returns:

a set containing the values (Objects) from Dbpedia's RDF store

retrieveRecords

protected java.util.Set<DataRecord> retrieveRecords(DataTemplate template)

Retrieve a set of data records for a particular DataTemplate. This method is used by the various getStructure methods.

Specified by:

retrieveRecords in class RecordAccessor

Parameters:

template - The data template specifying field mappings and descriptions

Returns:

the set of DataRecords for the template

setInitParameters

public void setInitParameters(java.util.Map<java.lang.String,java.lang.String> parameters)

Set any initialization parameters required by this data accessor. The key for the only parameters are query, which should contain the type query for Dbpedia, and the optional language parameter, which indicates the language used by the accessor. The default query should be in Solr format. If the language is not set, the accessor uses English.

Parameters:

parameters - a map of initialization parameters

setLanguage

public void setLanguage(java.lang.String language)

Set the language used by the accessor. The language string should be one of the standardized 2-character language strings.

Parameters:

language - the specifier for the language

setQuery

public void setQuery(java.lang.String query)

Set the query used to identify records from Dbpedia. If the query string is of the form field=value, the Otherwise, the internal topic is set to the query. The topic should be something matching either the skos subject field, or the rdf type. The query will be converted to camel notation for RDF, and any spaces will be converted to underscores for skos subjects.

Specified by:

setQuery in class AbstractDataAccessor<DataRecord,DataRecord>

Parameters:

query - the query string