HSEARCH-1658 Expose configuration to enable Lucene Infostream

documentation/src/main/asciidoc/ch03.asciidoc

@@ -1097,6 +1097,11 @@ parallelism. If you have many cores and contention on the internal structures of
 becomes a bottleneck you should configure an higher value, at the cost of slightly higher memory
 consumption.
 |8
+
+|hibernate.search.​[default\|<indexname>].​indexwriter.infostream
+|Enable low level trace information about Lucene's internal components.
+Causes performance degradation, should only be used for troubleshooting purposes
+|false
 |===============
 
 

engine/src/main/java/org/hibernate/search/backend/configuration/impl/IndexWriterSetting.java

@@ -11,6 +11,7 @@
 import org.apache.lucene.index.IndexWriterConfig;
 import org.apache.lucene.index.LogByteSizeMergePolicy;
 import org.hibernate.search.util.configuration.impl.ConfigurationParseHelper;
+import org.hibernate.search.util.logging.impl.LoggerInfoStream;
 
 /**
  * Represents possible options to be applied to an
@@ -123,6 +124,22 @@ public void applySetting(IndexWriterConfig writerConfig, int value) {
 		public void applySetting(IndexWriterConfig writerConfig, int value) {
 			writerConfig.setMaxThreadStates( value );
 		}
+	},
+	/**
+	 * @see org.apache.lucene.index.IndexWriterConfig#setInfoStream(org.apache.lucene.util.InfoStream)
+	 */
+	INFOSTREAM ( "infostream" ) {
+		@Override
+		public Integer parseVal(String value) {
+			return INFOSTREAM.parseBoolean( value );
+		}
+		@Override
+		public void applySetting(IndexWriterConfig writerConfig, int value) {
+			boolean enableInfoStream = intToBoolean( value );
+			if ( enableInfoStream ) {
+				writerConfig.setInfoStream( new LoggerInfoStream() );
+			}
+		}
 	};
 
 	private static final Integer TRUE = 1;

engine/src/main/java/org/hibernate/search/util/logging/impl/Log.java

@@ -666,4 +666,8 @@ public interface Log extends BasicLogger {
 			+ "If you experience errors on this index you might need to remove the lock, or rebuild the index." )
 	void lockingFailureDuringInitialization(String directoryDescription);
 
+	@LogMessage(level = TRACE)
+	@Message(id = 226, value = "%s: %s" )
+	void logInfoStreamMessage(String componentName, String message);
+
 }

engine/src/main/java/org/hibernate/search/util/logging/impl/LoggerInfoStream.java

@@ -0,0 +1,33 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.util.logging.impl;
+
+import org.apache.lucene.util.InfoStream;
+
+import java.io.IOException;
+
+/**
+ * An implementation of {@link org.apache.lucene.util.InfoStream}
+ * that redirects output to a logger
+ */
+public class LoggerInfoStream extends InfoStream {
+
+	private final Log logger = LoggerFactory.make();
+
+	@Override
+	public void message(String component, String message) {
+		logger.logInfoStreamMessage( component, message );
+	}
+
+	@Override
+	public boolean isEnabled(String component) {
+		return true;
+	}
+
+	@Override
+	public void close() throws IOException { }
+}