fixed the main problem in graphhopper#112

Author: Peter

core/src/main/java/com/graphhopper/GraphHopper.java

@@ -72,6 +72,8 @@ public static void main( String[] strs ) throws Exception
     private boolean sortGraph = false;
     boolean removeZipped = true;
     private boolean elevation = false;
+    private LockFactory lockFactory = new NativeFSLockFactory();
+    private final String fileLockName = "write.lock";
     // for routing
     private boolean simplifyRequest = true;
     // for index
@@ -495,6 +497,27 @@ public GraphHopper init( CmdArgs args )
         sortGraph = args.getBool("graph.doSort", sortGraph);
         removeZipped = args.getBool("graph.removeZipped", removeZipped);
         turnCosts = args.getBool("graph.turnCosts", turnCosts);
+        if (args.get("graph.locktype", "native").equals("simple"))
+            lockFactory = new SimpleFSLockFactory();
+        else
+            lockFactory = new NativeFSLockFactory();
+
+        // elevation
+        String eleProviderStr = args.get("graph.elevation.provider", "noop").toLowerCase();
+        String cacheDirStr = args.get("graph.elevation.cachedir", "");
+        String baseURL = args.get("graph.elevation.baseurl", "");
+        DAType elevationDAType = DAType.fromString(args.get("graph.elevation.dataaccess", "MMAP"));
+        ElevationProvider tmpProvider = ElevationProvider.NOOP;
+        if (eleProviderStr.equalsIgnoreCase("srtm"))
+            tmpProvider = new SRTMProvider();
+        // later:
+//        else if(eleProviderStr.startsWith("cgiar:"))        
+//            eleProvider = new CGIARProvider().setCacheDir(new File());        
+
+        tmpProvider.setCacheDir(new File(cacheDirStr));
+        tmpProvider.setBaseURL(baseURL);
+        tmpProvider.setInMemory(elevationDAType.isInMemory());
+        setElevationProvider(tmpProvider);
 
         // optimizable prepare
         minNetworkSize = args.getInt("prepare.minNetworkSize", minNetworkSize);
@@ -519,23 +542,6 @@ public GraphHopper init( CmdArgs args )
         workerThreads = args.getInt("osmreader.workerThreads", workerThreads);
         enableInstructions = args.getBool("osmreader.instructions", enableInstructions);
 
-        // elevation
-        String eleProviderStr = args.get("graph.elevation.provider", "noop").toLowerCase();
-        String cacheDirStr = args.get("graph.elevation.cachedir", "");
-        String baseURL = args.get("graph.elevation.baseurl", "");
-        DAType elevationDAType = DAType.fromString(args.get("graph.elevation.dataaccess", "MMAP"));
-        ElevationProvider tmpProvider = ElevationProvider.NOOP;
-        if (eleProviderStr.equalsIgnoreCase("srtm"))
-            tmpProvider = new SRTMProvider();
-        // later:
-//        else if(eleProviderStr.startsWith("cgiar:"))        
-//            eleProvider = new CGIARProvider().setCacheDir(new File());        
-
-        tmpProvider.setCacheDir(new File(cacheDirStr));
-        tmpProvider.setBaseURL(baseURL);
-        tmpProvider.setInMemory(elevationDAType.isInMemory());
-        setElevationProvider(tmpProvider);
-
         // index
         preciseIndexResolution = args.getInt("index.highResolution", preciseIndexResolution);
         return this;
@@ -571,18 +577,34 @@ public GraphHopper importOrLoad()
     private GraphHopper process( String graphHopperLocation )
     {
         setGraphHopperLocation(graphHopperLocation);
+        Lock lock = null;
         try
         {
-            importData();
-            graph.getProperties().put("osmreader.import.date", formatDateTime(new Date()));
-        } catch (IOException ex)
+            if (graph.getDirectory().getDefaultType().isStoring())
+            {
+                lockFactory.setLockDir(new File(graphHopperLocation));
+                lock = lockFactory.create(fileLockName);
+                if (!lock.obtain())
+                    throw new RuntimeException("To avoid multiple writers we need to obtain a lock but it failed. In " + graphHopperLocation);
+            }
+
+            try
+            {
+                importData();
+                graph.getProperties().put("osmreader.import.date", formatDateTime(new Date()));
+            } catch (IOException ex)
+            {
+                throw new RuntimeException("Cannot parse OSM file " + getOSMFile(), ex);
+            }
+            cleanUp();
+            optimize();
+            postProcessing();
+            flush();
+        } finally
         {
-            throw new RuntimeException("Cannot parse OSM file " + getOSMFile(), ex);
+            if (lock != null)
+                lock.release();
         }
-        cleanUp();
-        optimize();
-        postProcessing();
-        flush();
         return this;
     }
 
@@ -676,12 +698,29 @@ else if (turnCosts)
             graph = new GraphHopperStorage(dir, encodingManager, hasElevation());
 
         graph.setSegmentSize(defaultSegmentSize);
-        if (!graph.loadExisting())
-            return false;
 
-        postProcessing();
-        fullyLoaded = true;
-        return true;
+        Lock lock = null;
+        try
+        {
+            if (graph.getDirectory().getDefaultType().isStoring())
+            {
+                lockFactory.setLockDir(new File(ghLocation));
+                lock = lockFactory.create(fileLockName);
+                if (!lock.obtain())
+                    throw new RuntimeException("To avoid reading partial data we need to obtain the lock but it failed. In " + ghLocation + ", ");
+            }
+
+            if (!graph.loadExisting())
+                return false;
+
+            postProcessing();
+            fullyLoaded = true;
+            return true;
+        } finally
+        {
+            if (lock != null)
+                lock.release();
+        }
     }
 
     /**

core/src/main/java/com/graphhopper/storage/Lock.java

@@ -0,0 +1,35 @@
+/*
+ *  Licensed to Peter Karich under one or more contributor license
+ *  agreements. See the NOTICE file distributed with this work for
+ *  additional information regarding copyright ownership.
+ *
+ *  Peter Karich 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.graphhopper.storage;
+
+/**
+ * A write lock. Influenced by Lucene code
+ * <p>
+ * @author Peter Karich
+ */
+public interface Lock
+{
+    String getName();
+
+    boolean obtain();
+
+    boolean isLocked();
+
+    void release();
+}

core/src/main/java/com/graphhopper/storage/LockFactory.java

@@ -0,0 +1,33 @@
+/*
+ *  Licensed to Peter Karich under one or more contributor license
+ *  agreements. See the NOTICE file distributed with this work for
+ *  additional information regarding copyright ownership.
+ *
+ *  Peter Karich 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.graphhopper.storage;
+
+import java.io.File;
+
+/**
+ * @author Peter Karich
+ */
+public interface LockFactory
+{
+    void setLockDir( File lockDir );
+
+    Lock create( String fileName );
+
+    void forceRemove( String fileName );
+}