lucene 4: extrace Lucene#readSegmentsInfo, and use it where applicable

src/main/java/org/elasticsearch/common/lucene/Lucene.java

@@ -23,6 +23,7 @@ import org.apache.lucene.analysis.core.KeywordAnalyzer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.index.*;
 import org.apache.lucene.search.*;
+import org.apache.lucene.store.Directory;
 import org.apache.lucene.util.Version;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -40,7 +41,7 @@ import java.lang.reflect.Field;
  */
 public class Lucene {
 
-    public static final Version VERSION = Version.LUCENE_36;
+    public static final Version VERSION = Version.LUCENE_40;
     public static final Version ANALYZER_VERSION = VERSION;
     public static final Version QUERYPARSER_VERSION = VERSION;
 
@@ -57,6 +58,9 @@ public class Lucene {
         if (version == null) {
             return defaultVersion;
         }
+        if ("4.0".equals(version)) {
+            return Version.LUCENE_40;
+        }
         if ("3.6".equals(version)) {
             return Version.LUCENE_36;
         }
@@ -82,6 +86,27 @@ public class Lucene {
         return defaultVersion;
     }
 
+    /**
+     * Reads the segments infos, returning null if it doesn't exists
+     */
+    @Nullable
+    public static SegmentInfos readSegmentInfosIfExists(Directory directory) {
+        try {
+            return readSegmentInfos(directory);
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    /**
+     * Reads the segments infos, failing if it fails to load
+     */
+    public static SegmentInfos readSegmentInfos(Directory directory) throws IOException {
+        final SegmentInfos sis = new SegmentInfos();
+        sis.read(directory);
+        return sis;
+    }
+
     public static long count(IndexSearcher searcher, Query query) throws IOException {
         TotalHitCountCollector countCollector = new TotalHitCountCollector();
         // we don't need scores, so wrap it in a constant score query

src/main/java/org/elasticsearch/index/engine/robin/RobinEngine.java

@@ -23,9 +23,6 @@ import com.google.common.collect.Lists;
 import org.apache.lucene.index.*;
 import org.apache.lucene.search.*;
 import org.apache.lucene.store.AlreadyClosedException;
-import org.apache.lucene.store.Directory;
-import org.apache.lucene.store.IOContext;
-import org.apache.lucene.util.IOUtils;
 import org.elasticsearch.ElasticSearchException;
 import org.elasticsearch.ElasticSearchIllegalStateException;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
@@ -244,7 +241,7 @@ public class RobinEngine extends AbstractIndexShardComponent implements Engine {
                 // commit on a just opened writer will commit even if there are no changes done to it
                 // we rely on that for the commit data translog id key
                 if (DirectoryReader.indexExists(store.directory())) {
-                    Map<String, String> commitUserData = getCommitUserData(store.directory());
+                    Map<String, String> commitUserData = Lucene.readSegmentInfos(store.directory()).getUserData();
                     if (commitUserData.containsKey(Translog.TRANSLOG_ID_KEY)) {
                         translogIdGenerator.set(Long.parseLong(commitUserData.get(Translog.TRANSLOG_ID_KEY)));
                     } else {
@@ -859,7 +856,7 @@ public class RobinEngine extends AbstractIndexShardComponent implements Engine {
                             indexWriter.commit(MapBuilder.<String, String>newMapBuilder().put(Translog.TRANSLOG_ID_KEY, Long.toString(translogId)).map());
                             if (flush.force()) {
                                 // if we force, we might not have committed, we need to check that its the same id
-                                Map<String, String> commitUserData = getCommitUserData(store.directory());
+                                Map<String, String> commitUserData = Lucene.readSegmentInfos(store.directory()).getUserData();
                                 long committedTranslogId = Long.parseLong(commitUserData.get(Translog.TRANSLOG_ID_KEY));
                                 if (committedTranslogId != translogId) {
                                     // we did not commit anything, revert to the old translog
@@ -1529,13 +1526,4 @@ public class RobinEngine extends AbstractIndexShardComponent implements Engine {
             return searcher;
         }
     }
-    
-    /**
-     * Reads the latest commit and loads the userdata
-     */
-    private static final Map<String, String> getCommitUserData(final Directory directory) throws IOException {
-        final SegmentInfos sis = new SegmentInfos();
-        sis.read(directory);
-        return sis.getUserData();
-    }
 }

src/main/java/org/elasticsearch/index/gateway/blobstore/BlobStoreIndexShardGateway.java

@@ -22,7 +22,7 @@ package org.elasticsearch.index.gateway.blobstore;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Lists;
-import org.apache.lucene.index.IndexReader;
+import org.apache.lucene.index.DirectoryReader;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
@@ -32,6 +32,7 @@ import org.elasticsearch.common.blobstore.*;
 import org.elasticsearch.common.io.FastByteArrayInputStream;
 import org.elasticsearch.common.io.FastByteArrayOutputStream;
 import org.elasticsearch.common.io.stream.BytesStreamInput;
+import org.elasticsearch.common.lucene.Lucene;
 import org.elasticsearch.common.lucene.store.InputStreamIndexInput;
 import org.elasticsearch.common.lucene.store.ThreadSafeInputStreamIndexInput;
 import org.elasticsearch.common.settings.Settings;
@@ -609,8 +610,8 @@ public abstract class BlobStoreIndexShardGateway extends AbstractIndexShardCompo
         // read the gateway data persisted
         long version = -1;
         try {
-            if (IndexReader.indexExists(store.directory())) {
+            if (DirectoryReader.indexExists(store.directory())) {
-                version = IndexReader.getCurrentVersion(store.directory());
+                version = Lucene.readSegmentInfos(store.directory()).getVersion();
             }
         } catch (IOException e) {
             throw new IndexShardGatewayRecoveryException(shardId(), "Failed to fetch index version after copying it over", e);

src/main/java/org/elasticsearch/index/gateway/local/LocalIndexShardGateway.java

@@ -20,9 +20,9 @@
 package org.elasticsearch.index.gateway.local;
 
 import com.google.common.io.Closeables;
-import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.IndexWriter;
 import org.apache.lucene.index.IndexWriterConfig;
+import org.apache.lucene.index.SegmentInfos;
 import org.elasticsearch.ElasticSearchException;
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.io.stream.InputStreamStreamInput;
@@ -49,7 +49,6 @@ import java.io.EOFException;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.util.Map;
 import java.util.concurrent.ScheduledFuture;
 
 /**
@@ -101,12 +100,12 @@ public class LocalIndexShardGateway extends AbstractIndexShardComponent implemen
         long version = -1;
         long translogId = -1;
         try {
-            if (IndexReader.indexExists(indexShard.store().directory())) {
+            SegmentInfos si = Lucene.readSegmentInfosIfExists(indexShard.store().directory());
+            if (si != null) {
                 if (indexShouldExists) {
-                    version = IndexReader.getCurrentVersion(indexShard.store().directory());
+                    version = si.getVersion();
-                    Map<String, String> commitUserData = IndexReader.getCommitUserData(indexShard.store().directory());
+                    if (si.getUserData().containsKey(Translog.TRANSLOG_ID_KEY)) {
-                    if (commitUserData.containsKey(Translog.TRANSLOG_ID_KEY)) {
+                        translogId = Long.parseLong(si.getUserData().get(Translog.TRANSLOG_ID_KEY));
-                        translogId = Long.parseLong(commitUserData.get(Translog.TRANSLOG_ID_KEY));
                     } else {
                         translogId = version;
                     }