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From wik...@apache.org
Subject [2/9] git commit: MARMOTTA-556: added basic service implementation of Linked Data Fragments
Date Mon, 27 Oct 2014 08:01:38 GMT
MARMOTTA-556: added basic service implementation of Linked Data Fragments


Project: http://git-wip-us.apache.org/repos/asf/marmotta/repo
Commit: http://git-wip-us.apache.org/repos/asf/marmotta/commit/d0dbb7d5
Tree: http://git-wip-us.apache.org/repos/asf/marmotta/tree/d0dbb7d5
Diff: http://git-wip-us.apache.org/repos/asf/marmotta/diff/d0dbb7d5

Branch: refs/heads/MARMOTTA-556
Commit: d0dbb7d59c63780ac5acfb1f18a49769b3c8e550
Parents: 1a96333
Author: Sergio Fernández <wikier@apache.org>
Authored: Fri Oct 24 18:31:25 2014 +0200
Committer: Sergio Fernández <wikier@apache.org>
Committed: Fri Oct 24 18:31:25 2014 +0200

----------------------------------------------------------------------
 platform/marmotta-ldf/pom.xml                   |   4 +
 .../marmotta/platform/ldf/api/LdfService.java   |  65 +++++++++++
 .../platform/ldf/logging/LdfLoggingModule.java  |  55 +++++++++
 .../platform/ldf/services/LdfServiceImpl.java   |  62 ++++++++++
 .../platform/ldf/sesame/PagedRDFHandler.java    | 114 +++++++++++++++++++
 5 files changed, 300 insertions(+)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/marmotta/blob/d0dbb7d5/platform/marmotta-ldf/pom.xml
----------------------------------------------------------------------
diff --git a/platform/marmotta-ldf/pom.xml b/platform/marmotta-ldf/pom.xml
index cc3fd49..de1ae45 100644
--- a/platform/marmotta-ldf/pom.xml
+++ b/platform/marmotta-ldf/pom.xml
@@ -165,6 +165,10 @@
             <version>${project.version}</version>
         </dependency>
         <dependency>
+            <groupId>org.openrdf.sesame</groupId>
+            <artifactId>sesame-rio-api</artifactId>
+        </dependency>
+        <dependency>
             <groupId>org.jboss.resteasy</groupId>
             <artifactId>resteasy-cdi</artifactId>
         </dependency>

http://git-wip-us.apache.org/repos/asf/marmotta/blob/d0dbb7d5/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/api/LdfService.java
----------------------------------------------------------------------
diff --git a/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/api/LdfService.java
b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/api/LdfService.java
new file mode 100644
index 0000000..2d7e3e2
--- /dev/null
+++ b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/api/LdfService.java
@@ -0,0 +1,65 @@
+package org.apache.marmotta.platform.ldf.api;
+
+import org.openrdf.model.Model;
+import org.openrdf.model.Resource;
+import org.openrdf.model.URI;
+import org.openrdf.rio.RDFFormat;
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import org.openrdf.model.Value;
+import org.openrdf.repository.RepositoryException;
+
+import java.io.OutputStream;
+
+/**
+ * Linked Media Fragments service
+ *
+ * @author Sergio Fernández
+ */
+public interface LdfService {
+
+    /**
+     * Writes a fragment matching the specified triple fragment pattern
+     * specified (null values are wildcards).
+     *
+     * @param subject fragment subject
+     * @param predicate fragmnent predicate
+     * @param object fragment object
+     * @param offset index at which to start the page
+     * @param limit maximum number of triples
+     * @param format RDF serialization
+     * @param out output stream where write the fragment
+     */
+    void writeFragment(URI subject, URI predicate, Value object, int offset, int limit, RDFFormat
format, OutputStream out) throws RepositoryException;
+
+    /**
+     * Writes a fragment matching the specified quad fragment pattern
+     * specified (null values are wildcards).
+     *
+     * @param subject fragment subject
+     * @param predicate fragmnent predicate
+     * @param object fragment object
+     * @param context named graph
+     * @param offset index at which to start the page
+     * @param limit maximum number of triples
+     * @param format RDF serialization
+     * @param out output stream where write the fragment
+     */
+    void writeFragment(URI subject, URI predicate, Value object, Resource context, int offset,
int limit, RDFFormat format, OutputStream out) throws RepositoryException;
+
+}

http://git-wip-us.apache.org/repos/asf/marmotta/blob/d0dbb7d5/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/logging/LdfLoggingModule.java
----------------------------------------------------------------------
diff --git a/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/logging/LdfLoggingModule.java
b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/logging/LdfLoggingModule.java
new file mode 100644
index 0000000..54a6495
--- /dev/null
+++ b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/logging/LdfLoggingModule.java
@@ -0,0 +1,55 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.marmotta.platform.ldf.logging;
+
+import ch.qos.logback.classic.Level;
+import org.apache.marmotta.platform.core.logging.BaseLoggingModule;
+
+import javax.enterprise.context.ApplicationScoped;
+import java.util.Collection;
+import java.util.Collections;
+
+/**
+ * Logging Module for LDF
+ *
+ * @author Sergio Fernández
+ */
+@ApplicationScoped
+public class LdfLoggingModule extends BaseLoggingModule {
+
+    @Override
+    public String getId() {
+        return "ldf";
+    }
+
+    @Override
+    public String getName() {
+        return "LDF";
+    }
+
+    @Override
+    public Collection<String> getPackages() {
+        return Collections.singleton("org.apache.marmotta.platform.ldf");
+    }
+
+    @Override
+    public Level getDefaultLevel() {
+        return Level.DEBUG;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/marmotta/blob/d0dbb7d5/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/services/LdfServiceImpl.java
----------------------------------------------------------------------
diff --git a/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/services/LdfServiceImpl.java
b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/services/LdfServiceImpl.java
new file mode 100644
index 0000000..49ca8ff
--- /dev/null
+++ b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/services/LdfServiceImpl.java
@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.marmotta.platform.ldf.services;
+
+import org.apache.marmotta.commons.sesame.repository.ResultUtils;
+import org.apache.marmotta.platform.core.api.triplestore.SesameService;
+import org.apache.marmotta.platform.ldf.api.LdfService;
+import org.apache.marmotta.platform.ldf.sesame.PagedRDFHandler;
+import org.openrdf.model.*;
+import org.openrdf.repository.RepositoryConnection;
+import org.openrdf.repository.RepositoryException;
+import org.openrdf.repository.RepositoryResult;
+import org.openrdf.rio.*;
+
+import javax.inject.Inject;
+import java.io.OutputStream;
+
+/**
+ * Linked Media Fragments service implementation
+ *
+ * @author Sergio Fernández
+ */
+public class LdfServiceImpl implements LdfService {
+
+    @Inject
+    private SesameService sesameService;
+
+    @Override
+    public void writeFragment(URI subject, URI predicate, Value object, int offset, int limit,
RDFFormat format, OutputStream out) throws RepositoryException {
+        writeFragment(subject, predicate, object, null, offset, limit, format, out);
+    }
+
+    @Override
+    public void writeFragment(URI subject, URI predicate, Value object, Resource context,
int offset, int limit, RDFFormat format, OutputStream out) throws RepositoryException {
+        final RepositoryConnection conn = sesameService.getConnection();
+        try {
+            conn.begin();
+            RepositoryResult<Statement> statements = conn.getStatements(subject, predicate,
object, true, context);
+            RDFHandler handler = new PagedRDFHandler(Rio.createWriter(format, out), offset,
limit);
+            Rio.write(ResultUtils.iterable(statements), handler);
+        } catch (RDFHandlerException e) {
+            e.printStackTrace();
+        } finally {
+            conn.close();
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/marmotta/blob/d0dbb7d5/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/sesame/PagedRDFHandler.java
----------------------------------------------------------------------
diff --git a/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/sesame/PagedRDFHandler.java
b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/sesame/PagedRDFHandler.java
new file mode 100644
index 0000000..36f59cf
--- /dev/null
+++ b/platform/marmotta-ldf/src/main/java/org/apache/marmotta/platform/ldf/sesame/PagedRDFHandler.java
@@ -0,0 +1,114 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.marmotta.platform.ldf.sesame;
+
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
+import org.openrdf.model.Literal;
+import org.openrdf.model.Resource;
+import org.openrdf.model.Statement;
+import org.openrdf.rio.RDFHandler;
+import org.openrdf.rio.RDFHandlerException;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * Paginates statements before sending them to the delegated RDFHandler.
+ * (TODO: find a more performance solution)
+ *
+ * @author Sergio Fernández
+ */
+public class PagedRDFHandler implements RDFHandler {
+
+    private List<Statement> statements;
+    private RDFHandler handler;
+    private int offset;
+    private int limit;
+
+    /**
+     * Constructs a PagedRDFHandler with a delegate handler
+     *
+     * @param handler The handler to delegate the calls to
+     */
+    public PagedRDFHandler(RDFHandler handler, int offset, int limit) {
+        super();
+        this.statements = new ArrayList<>();
+        this.handler = handler;
+        this.offset = offset;
+        this.limit = limit;
+    }
+
+    @Override
+    public void startRDF() throws RDFHandlerException {
+        handler.startRDF();
+    }
+
+    @Override
+    public void endRDF() throws RDFHandlerException {
+        //first order by a fixed criteria
+        Collections.sort(statements, new Comparator<Statement>() {
+            @Override
+            public int compare(Statement s1, Statement s2) {
+                int subjectComparison = s1.getSubject().stringValue().compareTo(s2.getSubject().stringValue());
+                int predicatedComparison = s1.getPredicate().stringValue().compareTo(s2.getPredicate().stringValue());
+
+                if (subjectComparison != 0) {
+                    return subjectComparison;
+                } else if (predicatedComparison != 0) {
+                    return predicatedComparison;
+                } else if((s1.getObject() instanceof Literal) && (s2.getObject()
instanceof Resource)) {
+                    return 1;
+                } else if((s1.getObject() instanceof Resource) && (s2.getObject()
instanceof Literal)) {
+                    return -1;
+                } else {
+                    return s1.getObject().stringValue().compareTo(s2.getObject().stringValue());
+                }
+            }
+        });
+
+        //then filter
+        List<Statement> filteredStatements = Lists.newArrayList(Iterables.limit(statements,
20));
+
+        //send statements to delegate writer
+        for (Statement statement : filteredStatements) {
+            handler.handleStatement(statement);
+        }
+
+        //and actually end the rdf
+        handler.endRDF();
+    }
+
+    @Override
+    public void handleNamespace(String prefix, String uri) throws RDFHandlerException {
+        handler.handleNamespace(prefix, uri);
+    }
+
+    @Override
+    public void handleStatement(Statement statement) throws RDFHandlerException {
+        statements.add(statement);
+    }
+
+    @Override
+    public void handleComment(String comment) throws RDFHandlerException {
+        handler.handleComment(comment);
+    }
+
+}


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