/// <summary>
/// Tries to load an object based on information from the Configuration Graph
/// </summary>
/// <param name="g">Configuration Graph</param>
/// <param name="objNode">Object Node</param>
/// <param name="targetType">Target Type</param>
/// <param name="obj">Output Object</param>
/// <returns></returns>
public bool TryLoadObject(IGraph g, INode objNode, Type targetType, out object obj)
{
obj = null;
INode index = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "index"));
//INode indexer = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "indexer"));
INode searcher = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "searcher"));
INode analyzer = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "analyzer"));
INode schema = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "schema"));
INode version = g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "version"));
Object tempIndex, tempAnalyzer, tempSchema;
int ver = 2900;
//Always check for the version
ver = ConfigurationLoader.GetConfigurationInt32(g, objNode, version, 2900);
switch (targetType.FullName)
{
case DefaultIndexSchema:
obj = new DefaultIndexSchema();
break;
case FullTextOptimiser:
//Need to get the Search Provider
INode providerNode = ConfigurationLoader.GetConfigurationNode(g, objNode, searcher);
if (providerNode == null) throw new DotNetRdfConfigurationException("Unable to load the Full Text Optimiser specified by the Node '" + objNode.ToString() + "' as there was no value specified for the required dnr-ft:searcher property");
Object tempSearcher = ConfigurationLoader.LoadObject(g, providerNode);
if (tempSearcher is IFullTextSearchProvider)
{
obj = new FullTextOptimiser((IFullTextSearchProvider)tempSearcher);
}
else
{
throw new DotNetRdfConfigurationException("Unable to load the Full Text Optimiser specified by the Node '" + objNode.ToString() + "' as the value specified for the dnr-ft:searcher property pointed to an object which could not be loaded as a type that implements the required IFullTextSearchProvider interface");
}
break;
case LuceneObjectsIndexer:
case LucenePredicatesIndexer:
case LuceneSubjectsIndexer:
case LuceneSearchProvider:
//For any Lucene Indexer/Search Provider need to know the Index, Analyzer and Schema to be used
//Then get the Index
tempIndex = ConfigurationLoader.GetConfigurationNode(g, objNode, index);
if (tempIndex == null) throw new DotNetRdfConfigurationException("Unable to load the Lucene Indexer specified by the Node '" + objNode.ToString() + "' as there was no value specified for the required dnr-ft:index property");
tempIndex = ConfigurationLoader.LoadObject(g, (INode)tempIndex);
if (tempIndex is Directory)
{
//Next get the Analyzer (assume Standard if none specified)
tempAnalyzer = ConfigurationLoader.GetConfigurationNode(g, objNode, analyzer);
if (tempAnalyzer == null)
{
tempAnalyzer = new StandardAnalyzer(this.GetLuceneVersion(ver));
}
else
{
tempAnalyzer = ConfigurationLoader.LoadObject(g, (INode)tempAnalyzer);
}
if (tempAnalyzer is Analyzer)
{
//Finally get the Schema (assume Default if none specified)
tempSchema = ConfigurationLoader.GetConfigurationNode(g, objNode, schema);
if (tempSchema == null)
{
tempSchema = new DefaultIndexSchema();
}
else
{
tempSchema = ConfigurationLoader.LoadObject(g, (INode)tempSchema);
}
if (tempSchema is IFullTextIndexSchema)
{
//Now we can create the Object
switch (targetType.FullName)
{
case LuceneObjectsIndexer:
obj = new LuceneObjectsIndexer((Directory)tempIndex, (Analyzer)tempAnalyzer, (IFullTextIndexSchema)tempSchema);
break;
case LucenePredicatesIndexer:
obj = new LucenePredicatesIndexer((Directory)tempIndex, (Analyzer)tempAnalyzer, (IFullTextIndexSchema)tempSchema);
break;
case LuceneSubjectsIndexer:
obj = new LuceneSubjectsIndexer((Directory)tempIndex, (Analyzer)tempAnalyzer, (IFullTextIndexSchema)tempSchema);
break;
case LuceneSearchProvider:
//Before the Search Provider has been loaded determine whether we need to carry out auto-indexing
List<INode> sources = ConfigurationLoader.GetConfigurationData(g, objNode, g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "buildIndexFor"))).ToList();
if (sources.Count > 0)
{
//If there are sources to index ensure we have an indexer to index with
INode indexerNode = ConfigurationLoader.GetConfigurationNode(g, objNode, g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "buildIndexWith")));
if (indexerNode == null) throw new DotNetRdfConfigurationException("Unable to load the Lucene Search Provider specified by the Node '" + objNode.ToString() + "' as there were values specified for the dnr-ft:buildIndexFor property but no dnr-ft:buildIndexWith property was found");
IFullTextIndexer indexer = ConfigurationLoader.LoadObject(g, indexerNode) as IFullTextIndexer;
if (indexer == null) throw new DotNetRdfConfigurationException("Unable to load the Lucene Search Provider specified by the Node '" + objNode.ToString() + "' as the value given for the dnr-ft:buildIndexWith property pointed to an Object which could not be loaded as a type that implements the required IFullTextIndexer interface");
try
{
//For Each Source load it and Index it
foreach (INode sourceNode in sources)
{
Object source = ConfigurationLoader.LoadObject(g, sourceNode);
if (source is ISparqlDataset)
{
indexer.Index((ISparqlDataset)source);
}
else if (source is ITripleStore)
{
foreach (IGraph graph in ((ITripleStore)source).Graphs)
{
indexer.Index(graph);
}
}
else if (source is IGraph)
{
indexer.Index((IGraph)source);
}
else
{
throw new DotNetRdfConfigurationException("Unable to load the Lucene Search Provider specified by the Node '" + objNode.ToString() + "' as a value given for the dnr-ft:buildIndexFor property ('" + sourceNode.ToString() + "') pointed to an Object which could not be loaded as a type that implements one of the required interfaces: IGraph, ITripleStore or ISparqlDataset");
}
}
}
finally
{
indexer.Dispose();
}
}
//Then we actually load the Search Provider
obj = new LuceneSearchProvider(this.GetLuceneVersion(ver), (Directory)tempIndex, (Analyzer)tempAnalyzer, (IFullTextIndexSchema)tempSchema);
break;
}
}
else
{
throw new DotNetRdfConfigurationException("Unable to load the Lucene Indexer specified by the Node '" + objNode.ToString() + "' as the value given for the dnr-ft:schema property pointed to an Object which could not be loaded as a type that implements the required IFullTextIndexSchema interface");
}
}
else
{
throw new DotNetRdfConfigurationException("Unable to load the Lucene Indexer specified by the Node '" + objNode.ToString() + "' as the value given for the dnr-ft:analyzer property pointed to an Object which could not be loaded as a type that derives from the required Lucene.Net.Analysis.Analyzer type");
}
}
else
{
throw new DotNetRdfConfigurationException("Unable to load the Lucene Indexer specified by the Node '" + objNode.ToString() + "' as the value given for the dnr-ft:index property pointed to an Object which could not be loaded as a type that derives from the required Lucene.Net.Store.Directory type");
}
break;
default:
try
{
if (this._luceneAnalyzerType.IsAssignableFrom(targetType))
{
if (targetType.GetConstructor(new Type[] { typeof(LucVersion) }) != null)
{
obj = Activator.CreateInstance(targetType, new Object[] { this.GetLuceneVersion(ver) });
}
else
{
obj = Activator.CreateInstance(targetType);
}
}
else if (this._luceneDirectoryType.IsAssignableFrom(targetType))
{
String dir = ConfigurationLoader.GetConfigurationString(g, objNode, ConfigurationLoader.CreateConfigurationNode(g, ConfigurationLoader.PropertyFromFile));
if (dir != null)
{
try
{
obj = Activator.CreateInstance(targetType, new Object[] { dir });
}
catch
{
MethodInfo method = targetType.GetMethod("Open", new Type[] { typeof(DirInfo) });
if (method != null)
{
obj = method.Invoke(null, new Object[] { new DirInfo(ConfigurationLoader.ResolvePath(dir)) });
}
}
}
else
{
obj = Activator.CreateInstance(targetType);
}
//Ensure the Index if necessary
if (obj != null)
{
if (ConfigurationLoader.GetConfigurationBoolean(g, objNode, g.CreateUriNode(new Uri(FullTextHelper.FullTextConfigurationNamespace + "ensureIndex")), false))
{
IndexWriter writer = new IndexWriter((Directory)obj, new StandardAnalyzer(this.GetLuceneVersion(ver)));
writer.Close();
}
}
}
}
catch
{
//Since we know we don't allow loading of all analyzers and directories we allow for users to inject other object factories
//which may know how to load those specific instances
obj = null;
}
break;
}
return (obj != null);
}