Index: lucene/contrib/benchmark/CHANGES.txt
===================================================================
--- lucene/contrib/benchmark/CHANGES.txt	(revision 938459)
+++ lucene/contrib/benchmark/CHANGES.txt	(working copy)
@@ -2,6 +2,8 @@
 
 The Benchmark contrib package contains code for benchmarking Lucene in a variety of ways.
 
+4/27/2010: WriteLineDocTask now supports multi-threading. (Shai Erera)
+
 4/07/2010
   LUCENE-2377: Enable the use of NoMergePolicy and NoMergeScheduler by 
   CreateIndexTask. (Shai Erera)
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/AbstractQueryMaker.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/AbstractQueryMaker.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/AbstractQueryMaker.java	(working copy)
@@ -17,7 +17,6 @@
 
 import org.apache.lucene.search.Query;
 import org.apache.lucene.benchmark.byTask.utils.Config;
-import org.apache.lucene.benchmark.byTask.utils.Format;
 
 /**
  * Abstract base query maker. 
@@ -45,7 +44,7 @@
     StringBuffer sb = new StringBuffer();
     if (queries != null) {
       for (int i = 0; i < queries.length; i++) {
-        sb.append(i+". "+ Format.simpleName(queries[i].getClass())+" - "+queries[i].toString());
+        sb.append(i+". "+ queries[i].getClass().getSimpleName()+" - "+queries[i].toString());
         sb.append(newline);
       }
     }
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DirContentSource.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DirContentSource.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DirContentSource.java	(working copy)
@@ -40,8 +40,6 @@
  * denotes a relative path (<b>default=work</b>).
  * <li><b>docs.dir</b> - specifies the directory the Dir collection. Can be set
  * to a relative path if "work.dir" is also specified (<b>default=dir-out</b>).
- * <li><b>html.parser</b> - specifies the {@link HTMLParser} class to use for
- * parsing the TREC documents content (<b>default=DemoHTMLParser</b>).
  * </ul>
  */
 public class DirContentSource extends ContentSource {
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DocMaker.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DocMaker.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/DocMaker.java	(working copy)
@@ -333,7 +333,7 @@
     String col = "                  ";
     StringBuffer sb = new StringBuffer();
     String newline = System.getProperty("line.separator");
-    sb.append("------------> ").append(Format.simpleName(getClass())).append(" statistics (").append(printNum).append("): ").append(newline);
+    sb.append("------------> ").append(getClass().getSimpleName()).append(" statistics (").append(printNum).append("): ").append(newline);
     int nut = source.getTotalDocsCount();
     if (nut > lastPrintedNumUniqueTexts) {
       print = true;
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/LongToEnglishContentSource.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/LongToEnglishContentSource.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/LongToEnglishContentSource.java	(working copy)
@@ -1,34 +1,56 @@
 package org.apache.lucene.benchmark.byTask.feeds;
 
+/**
+ * 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.apache.lucene.util.English;
 
 import java.io.IOException;
 import java.util.Date;
 
-
 /**
- *
- *
- **/
+ * Creates documents whose content is a <code>long</code> number starting from
+ * <code>{@link Long#MIN_VALUE} + 10</code>.
+ */
 public class LongToEnglishContentSource extends ContentSource{
   private long counter = Long.MIN_VALUE + 10;
 
   @Override
   public void close() throws IOException {
-
   }
-  //TODO: reduce/clean up synchonization
+  
   @Override
   public synchronized DocData getNextDocData(DocData docData) throws NoMoreDataException, IOException {
     docData.clear();
-    docData.setBody(English.longToEnglish(counter));
-    docData.setName("doc_" + String.valueOf(counter));
-    docData.setTitle("title_" + String.valueOf(counter));
+    // store the current counter to avoid synchronization
+    long curCounter;
+    synchronized (this) {
+      curCounter = counter;
+    }    
+    docData.setBody(English.longToEnglish(curCounter));
+    docData.setName("doc_" + String.valueOf(curCounter));
+    docData.setTitle("title_" + String.valueOf(curCounter));
     docData.setDate(new Date());
-    if (counter == Long.MAX_VALUE){
-      counter = Long.MIN_VALUE + 10;//loop around
+    synchronized (this) {
+      if (counter == Long.MAX_VALUE){
+        counter = Long.MIN_VALUE + 10;//loop around
+      }
+      counter++;
     }
-    counter++;
     return docData;
   }
 
@@ -36,4 +58,5 @@
   public void resetInputs() throws IOException {
     counter = Long.MIN_VALUE + 10;
   }
+  
 }
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/TrecContentSource.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/TrecContentSource.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/feeds/TrecContentSource.java	(working copy)
@@ -32,7 +32,7 @@
 import java.util.zip.GZIPInputStream;
 
 import org.apache.lucene.benchmark.byTask.utils.Config;
-import org.apache.lucene.benchmark.byTask.utils.StringBufferReader;
+import org.apache.lucene.benchmark.byTask.utils.StringBuilderReader;
 import org.apache.lucene.util.ThreadInterruptedException;
 
 /**
@@ -53,7 +53,6 @@
  * </ul>
  */
 public class TrecContentSource extends ContentSource {
-  // TODO (3.0): change StringBuffer to StringBuilder
 
   private static final class DateFormatInfo {
     DateFormat[] dfs;
@@ -79,8 +78,8 @@
   };
 
   private ThreadLocal<DateFormatInfo> dateFormats = new ThreadLocal<DateFormatInfo>();
-  private ThreadLocal<StringBufferReader> trecDocReader = new ThreadLocal<StringBufferReader>();
-  private ThreadLocal<StringBuffer> trecDocBuffer = new ThreadLocal<StringBuffer>();
+  private ThreadLocal<StringBuilderReader> trecDocReader = new ThreadLocal<StringBuilderReader>();
+  private ThreadLocal<StringBuilder> trecDocBuffer = new ThreadLocal<StringBuilder>();
   private File dataDir = null;
   private ArrayList<File> inputFiles = new ArrayList<File>();
   private int nextFile = 0;
@@ -110,19 +109,19 @@
     return dfi;
   }
 
-  private StringBuffer getDocBuffer() {
-    StringBuffer sb = trecDocBuffer.get();
+  private StringBuilder getDocBuffer() {
+    StringBuilder sb = trecDocBuffer.get();
     if (sb == null) {
-      sb = new StringBuffer();
+      sb = new StringBuilder();
       trecDocBuffer.set(sb);
     }
     return sb;
   }
   
-  private Reader getTrecDocReader(StringBuffer docBuffer) {
-    StringBufferReader r = trecDocReader.get();
+  private Reader getTrecDocReader(StringBuilder docBuffer) {
+    StringBuilderReader r = trecDocReader.get();
     if (r == null) {
-      r = new StringBufferReader(docBuffer);
+      r = new StringBuilderReader(docBuffer);
       trecDocReader.set(r);
     } else {
       r.set(docBuffer);
@@ -131,7 +130,7 @@
   }
 
   // read until finding a line that starts with the specified prefix, or a terminating tag has been found.
-  private void read(StringBuffer buf, String prefix, boolean collectMatchLine,
+  private void read(StringBuilder buf, String prefix, boolean collectMatchLine,
                     boolean collectAll, String terminatingTag)
       throws IOException, NoMoreDataException {
     String sep = "";
@@ -248,7 +247,7 @@
         openNextFile();
       }
 
-      StringBuffer docBuf = getDocBuffer();
+      StringBuilder docBuf = getDocBuffer();
       
       // 1. skip until doc start
       docBuf.setLength(0);
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/PerfTask.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/PerfTask.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/PerfTask.java	(working copy)
@@ -23,7 +23,6 @@
 import org.apache.lucene.benchmark.byTask.stats.Points;
 import org.apache.lucene.benchmark.byTask.stats.TaskStats;
 import org.apache.lucene.benchmark.byTask.utils.Config;
-import org.apache.lucene.benchmark.byTask.utils.Format;
 
 /**
  * An abstract task to be tested for performance. <br>
@@ -67,7 +66,7 @@
 
   /** Should not be used externally */
   private PerfTask() {
-    name = Format.simpleName(getClass());
+    name = getClass().getSimpleName();
     if (name.endsWith("Task")) {
       name = name.substring(0, name.length() - 4);
     }
@@ -99,13 +98,7 @@
     this.maxDepthLogStart = config.get("task.max.depth.log",0);
 
     String logStepAtt = "log.step";
-    // TODO (1.5): call getClass().getSimpleName() instead.
-    String taskName = getClass().getName();
-    int idx = taskName.lastIndexOf('.');
-    // To support test internal classes. when we move to getSimpleName, this can be removed.
-    int idx2 = taskName.indexOf('$', idx);
-    if (idx2 != -1) idx = idx2;
-    String taskLogStepAtt = "log.step." + taskName.substring(idx + 1, taskName.length() - 4 /* w/o the 'Task' part */);
+    String taskLogStepAtt = "log.step." + name;
     if (config.get(taskLogStepAtt, null) != null) {
       logStepAtt = taskLogStepAtt;
     }
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.java	(working copy)
@@ -22,6 +22,7 @@
 import java.io.FileOutputStream;
 import java.io.OutputStream;
 import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -56,8 +57,9 @@
   private static final Matcher NORMALIZER = Pattern.compile("[\t\r\n]+").matcher("");
 
   private int docSize = 0;
-  private BufferedWriter lineFileOut = null;
+  private PrintWriter lineFileOut = null;
   private DocMaker docMaker;
+  private ThreadLocal<StringBuilder> threadBuffer = new ThreadLocal<StringBuilder>();
   
   public WriteLineDocTask(PerfRunData runData) throws Exception {
     super(runData);
@@ -85,7 +87,7 @@
       out = new BufferedOutputStream(out, 1 << 16);
       out = new CompressorStreamFactory().createCompressorOutputStream("bzip2", out);
     }
-    lineFileOut = new BufferedWriter(new OutputStreamWriter(out, "UTF-8"), 1 << 16);
+    lineFileOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(out, "UTF-8"), 1 << 16));
     docMaker = runData.getDocMaker();
   }
 
@@ -109,12 +111,15 @@
       f = doc.getField(DocMaker.DATE_FIELD);
       String date = f != null ? NORMALIZER.reset(f.stringValue()).replaceAll(" ") : "";
       
-      lineFileOut.write(title, 0, title.length());
-      lineFileOut.write(SEP);
-      lineFileOut.write(date, 0, date.length());
-      lineFileOut.write(SEP);
-      lineFileOut.write(body, 0, body.length());
-      lineFileOut.newLine();
+      StringBuilder sb = threadBuffer.get();
+      if (sb == null) {
+        sb = new StringBuilder();
+        threadBuffer.set(sb);
+      }
+      sb.setLength(0);
+      sb.append(title).append(SEP).append(date).append(SEP).append(body);
+      // lineFileOut is a PrintWriter, which synchronizes internally in println.
+      lineFileOut.println(sb.toString());
     }
     return 1;
   }
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/Format.java	(working copy)
@@ -107,19 +107,4 @@
     return res.substring(res.length() - col.length());
   }
 
-  /**
-   * Extract simple class name 
-   * @param cls class whose simple name is required 
-   * @return simple class name
-   */
-  public static String simpleName (Class<?> cls) {
-    String c = cls.getName();
-    String p = cls.getPackage().getName();
-    int k = c.lastIndexOf(p+".");
-    if (k<0) {
-      return c;
-    }
-    return c.substring(k+1+p.length());
-  }
-  
 }
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBufferReader.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBufferReader.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBufferReader.java	(working copy)
@@ -1,181 +0,0 @@
-package org.apache.lucene.benchmark.byTask.utils;
-
-/**
- * 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 java.io.IOException;
-import java.io.Reader;
-
-/**
- * Implements a {@link Reader} over a {@link StringBuffer} instance. Although
- * one can use {@link java.io.StringReader} by passing it
- * {@link StringBuffer#toString()}, it is better to use this class, as it
- * doesn't mark the passed-in {@link StringBuffer} as shared (which will cause
- * inner char[] allocations at the next append() attempt).<br>
- * Notes:
- * <ul>
- * <li>This implementation assumes the underlying {@link StringBuffer} is not
- * changed during the use of this {@link Reader} implementation.
- * <li>This implementation is thread-safe.
- * <li>The implementation looks very much like {@link java.io.StringReader} (for
- * the right reasons).
- * <li>If one wants to reuse that instance, then the following needs to be done:
- * <pre>
- * StringBuffer sb = new StringBuffer("some text");
- * Reader reader = new StringBufferReader(sb);
- * ... read from reader - don't close it ! ...
- * sb.setLength(0);
- * sb.append("some new text");
- * reader.reset();
- * ... read the new string from the reader ...
- * </pre>
- * </ul>
- */
-public class StringBufferReader extends Reader {
-  
-  // TODO (3.0): change to StringBuffer (including the name of the class)
-  
-  // The StringBuffer to read from.
-  private StringBuffer sb;
-
-  // The length of 'sb'.
-  private int length;
-
-  // The next position to read from the StringBuffer.
-  private int next = 0;
-
-  // The mark position. The default value 0 means the start of the text.
-  private int mark = 0;
-
-  public StringBufferReader(StringBuffer sb) {
-    set(sb);
-  }
-
-  /** Check to make sure that the stream has not been closed. */
-  private void ensureOpen() throws IOException {
-    if (sb == null) {
-      throw new IOException("Stream has already been closed");
-    }
-  }
-
-  @Override
-  public void close() {
-    synchronized (lock) {
-      sb = null;
-    }
-  }
-
-  /**
-   * Mark the present position in the stream. Subsequent calls to reset() will
-   * reposition the stream to this point.
-   * 
-   * @param readAheadLimit Limit on the number of characters that may be read
-   *        while still preserving the mark. Because the stream's input comes
-   *        from a StringBuffer, there is no actual limit, so this argument 
-   *        must not be negative, but is otherwise ignored.
-   * @exception IllegalArgumentException If readAheadLimit is < 0
-   * @exception IOException If an I/O error occurs
-   */
-  @Override
-  public void mark(int readAheadLimit) throws IOException {
-    if (readAheadLimit < 0){
-      throw new IllegalArgumentException("Read-ahead limit cannpt be negative: " + readAheadLimit);
-    }
-    synchronized (lock) {
-      ensureOpen();
-      mark = next;
-    }
-  }
-
-  @Override
-  public boolean markSupported() {
-    return true;
-  }
-
-  @Override
-  public int read() throws IOException {
-    synchronized (lock) {
-      ensureOpen();
-      return next >= length ? -1 : sb.charAt(next++);
-    }
-  }
-
-  @Override
-  public int read(char cbuf[], int off, int len) throws IOException {
-    synchronized (lock) {
-      ensureOpen();
-
-      // Validate parameters
-      if (off < 0 || off > cbuf.length || len < 0 || off + len > cbuf.length) {
-        throw new IndexOutOfBoundsException("off=" + off + " len=" + len + " cbuf.length=" + cbuf.length);
-      }
-
-      if (len == 0) {
-        return 0;
-      }
-
-      if (next >= length) {
-        return -1;
-      }
-
-      int n = Math.min(length - next, len);
-      sb.getChars(next, next + n, cbuf, off);
-      next += n;
-      return n;
-    }
-  }
-
-  @Override
-  public boolean ready() throws IOException {
-    synchronized (lock) {
-      ensureOpen();
-      return true;
-    }
-  }
-
-  @Override
-  public void reset() throws IOException {
-    synchronized (lock) {
-      ensureOpen();
-      next = mark;
-      length = sb.length();
-    }
-  }
-
-  public void set(StringBuffer sb) {
-    synchronized (lock) {
-      this.sb = sb;
-      length = sb.length();
-    }
-  }
-  @Override
-  public long skip(long ns) throws IOException {
-    synchronized (lock) {
-      ensureOpen();
-      if (next >= length) {
-        return 0;
-      }
-
-      // Bound skip by beginning and end of the source
-      long n = Math.min(length - next, ns);
-      n = Math.max(-next, n);
-      next += n;
-      return n;
-    }
-  }
-
-}
Index: lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBuilderReader.java
===================================================================
--- lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBuilderReader.java	(revision 938459)
+++ lucene/contrib/benchmark/src/java/org/apache/lucene/benchmark/byTask/utils/StringBuilderReader.java	(working copy)
@@ -21,22 +21,22 @@
 import java.io.Reader;
 
 /**
- * Implements a {@link Reader} over a {@link StringBuffer} instance. Although
+ * Implements a {@link Reader} over a {@link StringBuilder} instance. Although
  * one can use {@link java.io.StringReader} by passing it
- * {@link StringBuffer#toString()}, it is better to use this class, as it
- * doesn't mark the passed-in {@link StringBuffer} as shared (which will cause
+ * {@link StringBuilder#toString()}, it is better to use this class, as it
+ * doesn't mark the passed-in {@link StringBuilder} as shared (which will cause
  * inner char[] allocations at the next append() attempt).<br>
  * Notes:
  * <ul>
- * <li>This implementation assumes the underlying {@link StringBuffer} is not
+ * <li>This implementation assumes the underlying {@link StringBuilder} is not
  * changed during the use of this {@link Reader} implementation.
  * <li>This implementation is thread-safe.
  * <li>The implementation looks very much like {@link java.io.StringReader} (for
  * the right reasons).
  * <li>If one wants to reuse that instance, then the following needs to be done:
  * <pre>
- * StringBuffer sb = new StringBuffer("some text");
- * Reader reader = new StringBufferReader(sb);
+ * StringBuilder sb = new StringBuilder("some text");
+ * Reader reader = new StringBuilderReader(sb);
  * ... read from reader - don't close it ! ...
  * sb.setLength(0);
  * sb.append("some new text");
@@ -45,23 +45,21 @@
  * </pre>
  * </ul>
  */
-public class StringBufferReader extends Reader {
+public class StringBuilderReader extends Reader {
   
-  // TODO (3.0): change to StringBuffer (including the name of the class)
-  
-  // The StringBuffer to read from.
-  private StringBuffer sb;
+  // The StringBuilder to read from.
+  private StringBuilder sb;
 
   // The length of 'sb'.
   private int length;
 
-  // The next position to read from the StringBuffer.
+  // The next position to read from the StringBuilder.
   private int next = 0;
 
   // The mark position. The default value 0 means the start of the text.
   private int mark = 0;
 
-  public StringBufferReader(StringBuffer sb) {
+  public StringBuilderReader(StringBuilder sb) {
     set(sb);
   }
 
@@ -85,7 +83,7 @@
    * 
    * @param readAheadLimit Limit on the number of characters that may be read
    *        while still preserving the mark. Because the stream's input comes
-   *        from a StringBuffer, there is no actual limit, so this argument 
+   *        from a StringBuilder, there is no actual limit, so this argument 
    *        must not be negative, but is otherwise ignored.
    * @exception IllegalArgumentException If readAheadLimit is < 0
    * @exception IOException If an I/O error occurs
@@ -156,7 +154,7 @@
     }
   }
 
-  public void set(StringBuffer sb) {
+  public void set(StringBuilder sb) {
     synchronized (lock) {
       this.sb = sb;
       length = sb.length();
Index: lucene/contrib/benchmark/src/test/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTaskTest.java
===================================================================
--- lucene/contrib/benchmark/src/test/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTaskTest.java	(revision 938459)
+++ lucene/contrib/benchmark/src/test/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTaskTest.java	(working copy)
@@ -22,7 +22,9 @@
 import java.io.FileInputStream;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.util.HashSet;
 import java.util.Properties;
+import java.util.Set;
 
 import org.apache.commons.compress.compressors.CompressorStreamFactory;
 import org.apache.lucene.benchmark.BenchmarkTestCase;
@@ -97,6 +99,21 @@
     }
   }
   
+  // class has to be public so that Class.forName.newInstance() will work
+  public static final class ThreadingDocMaker extends DocMaker {
+  
+    @Override
+    public Document makeDocument() throws Exception {
+      Document doc = new Document();
+      String name = Thread.currentThread().getName();
+      doc.add(new Field(BODY_FIELD, "body_" + name, Store.NO, Index.NOT_ANALYZED_NO_NORMS));
+      doc.add(new Field(TITLE_FIELD, "title_" + name, Store.NO, Index.NOT_ANALYZED_NO_NORMS));
+      doc.add(new Field(DATE_FIELD, "date_" + name, Store.NO, Index.NOT_ANALYZED_NO_NORMS));
+      return doc;
+    }
+    
+  }
+
   private static final CompressorStreamFactory csFactory = new CompressorStreamFactory();
 
   private PerfRunData createPerfRunData(File file, boolean setBZCompress,
@@ -225,5 +242,49 @@
       br.close();
     }
   }
-  
+
+  public void testMultiThreaded() throws Exception {
+    File file = new File(getWorkDir(), "one-line");
+    PerfRunData runData = createPerfRunData(file, false, null, ThreadingDocMaker.class.getName());
+    final WriteLineDocTask wldt = new WriteLineDocTask(runData);
+    Thread[] threads = new Thread[10];
+    for (int i = 0; i < threads.length; i++) {
+      threads[i] = new Thread("t" + i) {
+        @Override
+        public void run() {
+          try {
+            wldt.doLogic();
+          } catch (Exception e) {
+            throw new RuntimeException(e);
+          }
+        }
+      };
+    }
+    
+    for (Thread t : threads) t.start();
+    for (Thread t : threads) t.join();
+    
+    wldt.close();
+    
+    Set<String> ids = new HashSet<String>();
+    BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file), "utf-8"));
+    try {
+      for (int i = 0; i < threads.length; i++) {
+        String line = br.readLine();
+        String[] parts = line.split(Character.toString(WriteLineDocTask.SEP));
+        assertEquals(3, parts.length);
+        // check that all thread names written are the same in the same line
+        String tname = parts[0].substring(parts[0].indexOf('_'));
+        ids.add(tname);
+        assertEquals(tname, parts[1].substring(parts[1].indexOf('_')));
+        assertEquals(tname, parts[2].substring(parts[2].indexOf('_')));
+      }
+      // only threads.length lines should exist
+      assertNull(br.readLine());
+      assertEquals(threads.length, ids.size());
+    } finally {
+      br.close();
+    }
+  }
+
 }