svn commit: r1442737 - /jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java

[sa...@apache.org]

Author: sallen
Date: Tue Feb  5 20:49:11 2013
New Revision: 1442737

URL: http://svn.apache.org/viewvc?rev=1442737&view=rev
Log:
Add an example of a non-streaming UpdateEngine.

Added:
    jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java

Added: jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java
URL: http://svn.apache.org/viewvc/jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java?rev=1442737&view=auto
==============================================================================
--- jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java (added)
+++ jena/trunk/jena-arq/src/main/java/com/hp/hpl/jena/sparql/modify/UpdateEngineNonStreaming.java Tue Feb  5 20:49:11 2013
@@ -0,0 +1,117 @@
+/*
+ * 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 com.hp.hpl.jena.sparql.modify;
+
+import com.hp.hpl.jena.sparql.engine.binding.Binding ;
+import com.hp.hpl.jena.sparql.modify.request.UpdateVisitor ;
+import com.hp.hpl.jena.sparql.util.Context ;
+import com.hp.hpl.jena.update.GraphStore ;
+import com.hp.hpl.jena.update.Update ;
+import com.hp.hpl.jena.update.UpdateRequest ;
+
+/**
+ * Default implementation of an update engine that does not stream data, instead it will build it up into an
+ * in-memory UpdateRequest, and then traverse it after all update operations have finished.
+ */
+public class UpdateEngineNonStreaming extends UpdateEngineBase 
+{
+    protected final UpdateRequest request;
+    
+    /**
+     * Creates a new Update Engine
+     * @param graphStore Graph Store the updates operate over
+     * @param initialBinding Initial Bindings
+     * @param context Execution Context
+     */
+    public UpdateEngineNonStreaming(GraphStore graphStore, Binding initialBinding, Context context)
+    {
+        super(graphStore, initialBinding, context) ;
+        request = new UpdateRequest();
+    }
+
+    @Override
+    public void startRequest()
+    {
+        // Do nothing, we will call startRequest() on the graphstore in the execute() method
+    }
+    
+    @Override
+    public void finishRequest()
+    {
+        // Do nothing, we will call finishRequest() on the graphstore in the execute() method
+    }
+    
+    /**
+     * Creates an {@link UpdateSink} that adds all update operations into an internal {@code UpdateRequest} object.
+     * After the last update operation has been added, the {@link #execute()} method is called.
+     */
+    @Override
+    public UpdateSink getUpdateSink()
+    {
+        // Override the close() method to call execute() when we're done accepting update operations
+        return new UpdateRequestSink(request)
+        {
+            @Override
+            public void close()
+            {
+                super.close();
+                execute();
+            }
+        };
+    }
+    
+    /**
+     * Called after all of the update operations have been added to {@link #request}.
+     */
+    protected void execute()
+    {
+        graphStore.startRequest() ;
+        UpdateVisitor worker = this.prepareWorker() ;
+        for ( Update up : request )
+        {
+            up.visit(worker) ;
+        }
+        graphStore.finishRequest();
+    }
+    
+    /**
+     * Creates the {@link UpdateVisitor} which will do the work of applying the updates
+     * @return The update visitor to be used to apply the updates
+     */
+    protected UpdateVisitor prepareWorker() {
+        return new UpdateEngineWorker(graphStore, startBinding, context) ;
+    }
+    
+    private static UpdateEngineFactory factory = new UpdateEngineFactory()
+    {
+        @Override
+        public boolean accept(GraphStore graphStore, Context context)
+        {
+            return true ;
+        }
+        
+        @Override
+        public UpdateEngine create(GraphStore graphStore, Binding initialBinding, Context context)
+        {
+            return new UpdateEngineNonStreaming(graphStore, initialBinding, context);
+        }
+    } ;
+
+    public static UpdateEngineFactory getFactory() { return factory ; }
+}