added the possibility to specify relevant IDataSourceType implementat…

…ions in the config file
LinkedDataFragments · Dec 25, 2015 · fc14a72 · fc14a72
1 parent 29a2efe
commit fc14a72
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Showing 2 changed files with 53 additions and 0 deletions.
diff --git a/config-example.json b/config-example.json
@@ -1,6 +1,11 @@
 {
   "title": "My Linked Data Fragments server",
 
+  "datasourcetypes": {
+    "HdtDatasource"       : "org.linkeddatafragments.datasource.hdt.HdtDataSourceType",
+    "JenaTDBDatasource"   : "org.linkeddatafragments.datasource.tdb.JenaTDBDataSourceType"
+  },
+
   "datasources": {
     "dbpedia": {
       "title": "DBPedia",

diff --git a/src/org/linkeddatafragments/config/ConfigReader.java b/src/org/linkeddatafragments/config/ConfigReader.java
@@ -5,6 +5,8 @@
 import java.util.Map;
 import java.util.Map.Entry;
 
+import org.linkeddatafragments.datasource.IDataSourceType;
+
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.gson.JsonParser;
@@ -13,8 +15,10 @@
  * Reads the configuration of a Linked Data Fragments server.
  *
  * @author Ruben Verborgh
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
 public class ConfigReader {
+    private final Map<String, IDataSourceType> dataSourceTypes = new HashMap<>();
     private final Map<String, JsonObject> dataSources = new HashMap<>();
     private final Map<String, String> prefixes = new HashMap<>();
     private final String baseURL;
@@ -28,6 +32,10 @@ public ConfigReader(Reader configReader) {
         JsonObject root = new JsonParser().parse(configReader).getAsJsonObject();
         this.baseURL = root.has("baseURL") ? root.getAsJsonPrimitive("baseURL").getAsString() : null;
 
+        for (Entry<String, JsonElement> entry : root.getAsJsonObject("datasourcetypes").entrySet()) {
+            final String className = entry.getValue().getAsString();
+            dataSourceTypes.put(entry.getKey(), initDataSouceType(className) );
+        }
         for (Entry<String, JsonElement> entry : root.getAsJsonObject("datasources").entrySet()) {
             JsonObject dataSource = entry.getValue().getAsJsonObject();
             this.dataSources.put(entry.getKey(), dataSource);
@@ -37,6 +45,15 @@ public ConfigReader(Reader configReader) {
         }
     }
 
+    /**
+     * Gets the data source types.
+     *
+     * @return a mapping of names of data source types to these types  
+     */
+    public Map<String, IDataSourceType> getDataSourceTypes() {
+        return dataSourceTypes;
+    }
+
     /**
      * Gets the data sources.
      *
@@ -58,4 +75,35 @@ public Map<String, String> getPrefixes() {
     public String getBaseURL() {
         return baseURL;
     }
+
+    protected IDataSourceType initDataSouceType( final String className )
+    {
+        final Class<?> c;
+        try {
+            c = Class.forName( className ); 
+        }
+        catch ( ClassNotFoundException e ) {
+            throw new IllegalArgumentException( "Class not found: " + className,
+                                                e );
+        }
+
+        final Object o;
+        try {
+            o = c.newInstance();
+        }
+        catch ( Exception e ) {
+            throw new IllegalArgumentException(
+                        "Creating an instance of class '" + className + "' " +
+                        "caused a " + e.getClass().getSimpleName() + ": " +
+                        e.getMessage(), e );
+        }
+
+        if ( ! (o instanceof IDataSourceType) )
+            throw new IllegalArgumentException(
+                        "Class '" + className + "' is not an implementation " +
+                        "of IDataSourceType." );
+
+        return (IDataSourceType) o;
+    }
+
 }