Merge pull request #1 from LinkedDataFragments/master

Olaf Hartig · Olaf Hartig · commit 38b4d9cbda92 · 2015-12-13T21:09:15.000+01:00
merging in latest changes from origin
diff --git a/src/org/linkeddatafragments/datasource/DataSource.java b/src/org/linkeddatafragments/datasource/DataSource.java
@@ -37,4 +37,7 @@ public String getDescription() {
     public String getTitle() {
         return this.title;
     };
+
+    @Override
+    public void close() {}
 }
diff --git a/src/org/linkeddatafragments/datasource/DataSourceFactory.java b/src/org/linkeddatafragments/datasource/DataSourceFactory.java
@@ -1,20 +1,16 @@
 package org.linkeddatafragments.datasource;
 
 import com.google.gson.JsonObject;
-import java.io.File;
-import java.io.IOException;
 import org.linkeddatafragments.exceptions.DataSourceException;
 import org.linkeddatafragments.exceptions.UnknownDataSourceTypeException;
 
 /**
  *
  * @author Miel Vander Sande
  * @author Bart Hanssens
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
  */
 public class DataSourceFactory {
-    public final static String HDT = "HdtDatasource";
-    public final static String JENA_TDB = "JenaTDBDatasource";
-
     /**
      * Create a datasource using a JSON config
      * 
@@ -25,28 +21,15 @@ public class DataSourceFactory {
     public static IDataSource create(JsonObject config) throws DataSourceException {
         String title = config.getAsJsonPrimitive("title").getAsString();
         String description = config.getAsJsonPrimitive("description").getAsString();
-        String type = config.getAsJsonPrimitive("type").getAsString();
+        String typeName = config.getAsJsonPrimitive("type").getAsString();
         
         JsonObject settings = config.getAsJsonObject("settings");
 
-        switch (type) {
-            case HDT:
-                try {
-                    File file = new File(settings.getAsJsonPrimitive("file").getAsString());
-                    return new HdtDataSource(title, description, file.getAbsolutePath());
-                } catch (IOException ex) {
-                    throw new DataSourceException(ex);
-                }
-                
-            case JENA_TDB:                
-                File file = new File(settings.getAsJsonPrimitive("directory").getAsString());
-                return new JenaTDBDataSource(title, description, file);
-                
-            default:
-                throw new UnknownDataSourceTypeException(type);
-
-        }
+        final IDataSourceType type = DataSourceTypesRegistry.getType(typeName);
+        if ( type == null )
+            throw new UnknownDataSourceTypeException(typeName);
 
+        return type.createDataSource( title, description, settings );
     }
 
 }
diff --git a/src/org/linkeddatafragments/datasource/DataSourceTypesRegistry.java b/src/org/linkeddatafragments/datasource/DataSourceTypesRegistry.java
@@ -0,0 +1,36 @@
+package org.linkeddatafragments.datasource;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A registry of {@link IDataSourceType}s.
+ *
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
+ */
+public class DataSourceTypesRegistry
+{
+    private static Map<String, IDataSourceType> registry =
+                                        new HashMap<String, IDataSourceType>();
+
+    public static synchronized IDataSourceType getType( final String typeName )
+    {
+        return registry.get( typeName );
+    }
+
+    public static synchronized boolean isRegistered( final String typeName )
+    {
+        return registry.containsKey( typeName );
+    }
+
+    public static synchronized void register( final String typeName,
+                                              final IDataSourceType type )
+    {
+        if ( registry.containsKey(typeName) ) {
+            throw new IllegalArgumentException( "The registry already " +
+                       "contains a type with the name '" + typeName + "'." );
+        }
+        registry.put( typeName, type );
+    }
+
+}
diff --git a/src/org/linkeddatafragments/datasource/HdtDataSourceType.java b/src/org/linkeddatafragments/datasource/HdtDataSourceType.java
@@ -0,0 +1,42 @@
+package org.linkeddatafragments.datasource;
+
+import java.io.File;
+import java.io.IOException;
+
+import org.linkeddatafragments.exceptions.DataSourceException;
+
+import com.google.gson.JsonObject;
+
+/**
+ * The type of HDT-backed Triple Pattern Fragment data sources.
+ *
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
+ */
+public class HdtDataSourceType implements IDataSourceType
+{
+    public static final String TYPE_NAME = "HdtDatasource";
+
+    public static void register() {
+        if ( ! DataSourceTypesRegistry.isRegistered(TYPE_NAME) ) {
+            DataSourceTypesRegistry.register( TYPE_NAME,
+                                              new HdtDataSourceType() );
+        }
+    }
+
+    @Override
+    public IDataSource createDataSource( final String title,
+                                         final String description,
+                                         final JsonObject settings )
+                                                     throws DataSourceException
+    {
+        final String fname = settings.getAsJsonPrimitive("file").getAsString();
+        final File file = new File( fname );
+        
+        try {
+            return new HdtDataSource(title, description, file.getAbsolutePath());
+        } catch (IOException ex) {
+            throw new DataSourceException(ex);
+        }
+    }
+
+}
diff --git a/src/org/linkeddatafragments/datasource/IDataSource.java b/src/org/linkeddatafragments/datasource/IDataSource.java
@@ -1,5 +1,7 @@
 package org.linkeddatafragments.datasource;
 
+import java.io.Closeable;
+
 import com.hp.hpl.jena.rdf.model.Property;
 import com.hp.hpl.jena.rdf.model.RDFNode;
 import com.hp.hpl.jena.rdf.model.Resource;
@@ -8,7 +10,7 @@
  * A data source of Basic Linked Data Fragments.
  * @author Ruben Verborgh
  */
-public interface IDataSource {
+public interface IDataSource extends Closeable {
     /**
      * Gets a page of the Basic Linked Data Fragment matching the specified triple pattern.
      * @param subject the subject (null to match any subject)
diff --git a/src/org/linkeddatafragments/datasource/IDataSourceType.java b/src/org/linkeddatafragments/datasource/IDataSourceType.java
@@ -0,0 +1,32 @@
+package org.linkeddatafragments.datasource;
+
+import org.linkeddatafragments.exceptions.DataSourceException;
+
+import com.google.gson.JsonObject;
+
+/**
+ * Represents types of {@link IDataSource}s that can be used to provide some
+ * Linked Data Fragments interface.
+ *
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
+ */
+public interface IDataSourceType
+{
+    /**
+     * Creates a data source of this type.
+     * 
+     * @param title
+     *        The title of the data source (as given in the config file).
+     * 
+     * @param description
+     *        The description of the data source (as given in the config file).
+     *
+     * @param settings
+     *        The properties of the data source to be created; usually, these
+     *        properties are given in the config file of the LDF server. 
+     */
+    IDataSource createDataSource( final String title,
+                                  final String description,
+                                  final JsonObject settings )
+                                                    throws DataSourceException;
+}
diff --git a/src/org/linkeddatafragments/datasource/JenaTDBDataSource.java b/src/org/linkeddatafragments/datasource/JenaTDBDataSource.java
@@ -1,8 +1,5 @@
 package org.linkeddatafragments.datasource;
 
-import com.hp.hpl.jena.graph.Graph;
-import com.hp.hpl.jena.graph.GraphStatisticsHandler;
-import com.hp.hpl.jena.graph.Node;
 import com.hp.hpl.jena.query.Dataset;
 import com.hp.hpl.jena.query.Query;
 import com.hp.hpl.jena.query.QueryExecution;
diff --git a/src/org/linkeddatafragments/datasource/JenaTDBDataSourceType.java b/src/org/linkeddatafragments/datasource/JenaTDBDataSourceType.java
@@ -0,0 +1,42 @@
+package org.linkeddatafragments.datasource;
+
+import java.io.File;
+
+import org.linkeddatafragments.exceptions.DataSourceException;
+
+import com.google.gson.JsonObject;
+
+/**
+ * The type of Triple Pattern Fragment data sources that are backed by
+ * a Jena TDB instance.
+ *
+ * @author <a href="http://olafhartig.de">Olaf Hartig</a>
+ */
+public class JenaTDBDataSourceType implements IDataSourceType
+{
+    public static final String TYPE_NAME = "JenaTDBDatasource";
+
+    public static void register() {
+        if ( ! DataSourceTypesRegistry.isRegistered(TYPE_NAME) ) {
+            DataSourceTypesRegistry.register( TYPE_NAME,
+                                              new JenaTDBDataSourceType() );
+        }
+    }
+
+    @Override
+    public IDataSource createDataSource( final String title,
+                                         final String description,
+                                         final JsonObject settings )
+                                                     throws DataSourceException
+    {
+        final String dname = settings.getAsJsonPrimitive("directory").getAsString();
+        final File dir = new File( dname );
+
+        try {
+            return new JenaTDBDataSource(title, description, dir);
+        } catch (Exception ex) {
+            throw new DataSourceException(ex);
+        }
+    }
+
+}
diff --git a/src/org/linkeddatafragments/exceptions/DataSourceNotFoundException.java b/src/org/linkeddatafragments/exceptions/DataSourceNotFoundException.java
@@ -0,0 +1,19 @@
+package org.linkeddatafragments.exceptions;
+
+import org.linkeddatafragments.datasource.IDataSource;
+
+/**
+ *
+ * @author mielvandersande
+ */
+public class DataSourceNotFoundException extends Exception {
+    private static final long serialVersionUID = 1L;
+
+    public DataSourceNotFoundException(Throwable cause) {
+        super(cause.getMessage());
+    }
+
+    public DataSourceNotFoundException(String dataSourceName) {
+        super("Data source " + dataSourceName + " not found.");
+    }  
+}
diff --git a/src/org/linkeddatafragments/servlet/TriplePatternFragmentServlet.java b/src/org/linkeddatafragments/servlet/TriplePatternFragmentServlet.java
@@ -18,6 +18,8 @@
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map.Entry;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import javax.servlet.ServletConfig;
@@ -31,10 +33,13 @@
 import org.apache.jena.riot.RDFLanguages;
 import org.linkeddatafragments.config.ConfigReader;
 import org.linkeddatafragments.datasource.DataSourceFactory;
+import org.linkeddatafragments.datasource.HdtDataSourceType;
 import org.linkeddatafragments.datasource.IDataSource;
 import org.linkeddatafragments.datasource.IndexDataSource;
+import org.linkeddatafragments.datasource.JenaTDBDataSourceType;
 import org.linkeddatafragments.datasource.TriplePatternFragment;
 import org.linkeddatafragments.exceptions.DataSourceException;
+import org.linkeddatafragments.exceptions.DataSourceNotFoundException;
 import org.linkeddatafragments.util.CommonResources;
 import org.linkeddatafragments.util.MIMEParse;
 
@@ -64,6 +69,11 @@ public class TriplePatternFragmentServlet extends HttpServlet {
     private final HashMap<String, IDataSource> dataSources = new HashMap<>();
     private final Collection<String> mimeTypes = new ArrayList<>();
 
+    public TriplePatternFragmentServlet() {
+        HdtDataSourceType.register();
+        JenaTDBDataSourceType.register();
+    }
+
     private File getConfigFile(ServletConfig config) throws IOException {
         String path = config.getServletContext().getRealPath("/");
         if (path == null) {
@@ -104,14 +114,27 @@ public void init(ServletConfig servletConfig) throws ServletException {
         }
     }
 
+    @Override
+    public void destroy()
+    {
+        for ( IDataSource dataSource : dataSources.values() ) {
+            try {
+                dataSource.close();
+            }
+            catch( Exception e ) {
+                // ignore
+            }
+        }   
+    }
+
     /**
      * Get the datasource
      *
      * @param request
      * @return
      * @throws IOException
      */
-    private IDataSource getDataSource(HttpServletRequest request) throws IOException {
+    private IDataSource getDataSource(HttpServletRequest request) throws DataSourceNotFoundException {
         String contextPath = request.getContextPath();
         String requestURI = request.getRequestURI();
 
@@ -126,7 +149,7 @@ private IDataSource getDataSource(HttpServletRequest request) throws IOException
         String dataSourceName = path.substring(1);
         IDataSource dataSource = dataSources.get(dataSourceName);
         if (dataSource == null) {
-            throw new IOException("Data source not found.");
+            throw new DataSourceNotFoundException(dataSourceName);
         }
         return dataSource;
     }
@@ -292,8 +315,15 @@ public void doGet(HttpServletRequest request, HttpServletResponse response) thro
 
             RDFDataMgr.write(response.getOutputStream(), output, contentType);
         } catch (IOException | URISyntaxException e) {
-            e.printStackTrace();
             throw new ServletException(e);
+        } catch (DataSourceNotFoundException ex) {
+            try {
+                response.setStatus(404);
+                response.getOutputStream().println(ex.getMessage());
+                response.getOutputStream().close();
+            } catch (IOException ex1) {
+                throw new ServletException(ex1);
+            }
         }
     }
 
diff --git a/src/test/java/org/linkeddatafragments/TestSuite.java b/src/test/java/org/linkeddatafragments/TestSuite.java
@@ -0,0 +1,25 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package test.java.org.linkeddatafragments;
+
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+
+import test.java.org.linkeddatafragments.datasource.HdtDataSourceTest;
+import test.java.org.linkeddatafragments.datasource.JenaTDBDataSourceTest;
+
+/**
+ *
+ * @author Bart Hanssens <bart.hanssens@fedict.be>
+ */
+@RunWith(Suite.class)
+@Suite.SuiteClasses({
+   HdtDataSourceTest.class,
+   JenaTDBDataSourceTest.class
+})
+public class TestSuite {
+    
+}
diff --git a/src/test/java/org/linkeddatafragments/datasource/DataSourceTest.java b/src/test/java/org/linkeddatafragments/datasource/DataSourceTest.java
diff --git a/src/test/java/org/linkeddatafragments/datasource/HdtDataSourceTest.java b/src/test/java/org/linkeddatafragments/datasource/HdtDataSourceTest.java
diff --git a/src/test/java/org/linkeddatafragments/datasource/JenaTDBDataSourceTest.java b/src/test/java/org/linkeddatafragments/datasource/JenaTDBDataSourceTest.java
diff --git a/src/test/resources/demo.nt b/src/test/resources/demo.nt

Original file line number	Diff line number	Diff line change
`@@ -37,4 +37,7 @@ public String getDescription() {`
`37`	`37`	`public String getTitle() {`
`38`	`38`	`return this.title;`
`39`	`39`	`};`
	`40`	`+`
	`41`	`+ @Override`
	`42`	`+ public void close() {}`
`40`	`43`	`}`