/// <summary>
/// Forcibly unlocks the index in the named directory.
/// <P>
/// Caution: this should only be used by failure recovery code,
/// when it is known that no other process nor thread is in fact
/// currently accessing this index.
/// </summary>
public static void Unlock(Directory directory)
{
directory.MakeLock(IndexWriter.WRITE_LOCK_NAME).Release();
}
internal readonly Codec Codec; // for writing new segments
/// <summary>
/// Constructs a new IndexWriter per the settings given in <code>conf</code>.
/// If you want to make "live" changes to this writer instance, use
/// <seealso cref="#getConfig()"/>.
///
/// <p>
/// <b>NOTE:</b> after ths writer is created, the given configuration instance
/// cannot be passed to another writer. If you intend to do so, you should
/// <seealso cref="IndexWriterConfig#clone() clone"/> it beforehand.
/// </summary>
/// <param name="d">
/// the index directory. The index is either created or appended
/// according <code>conf.getOpenMode()</code>. </param>
/// <param name="conf">
/// the configuration settings according to which IndexWriter should
/// be initialized. </param>
/// <exception cref="IOException">
/// if the directory cannot be read/written to, or if it does not
/// exist and <code>conf.getOpenMode()</code> is
/// <code>OpenMode.APPEND</code> or if there is any other low-level
/// IO error </exception>
public IndexWriter(Directory d, IndexWriterConfig conf)
{
/*if (!InstanceFieldsInitialized)
{
InitializeInstanceFields();
InstanceFieldsInitialized = true;
}*/
readerPool = new ReaderPool(this);
conf.SetIndexWriter(this); // prevent reuse by other instances
Config_Renamed = new LiveIndexWriterConfig(conf);
directory = d;
analyzer = Config_Renamed.Analyzer;
infoStream = Config_Renamed.InfoStream;
mergePolicy = Config_Renamed.MergePolicy;
mergePolicy.IndexWriter = this;
mergeScheduler = Config_Renamed.MergeScheduler;
Codec = Config_Renamed.Codec;
BufferedUpdatesStream = new BufferedUpdatesStream(infoStream);
PoolReaders = Config_Renamed.ReaderPooling;
WriteLock = directory.MakeLock(WRITE_LOCK_NAME);
if (!WriteLock.Obtain(Config_Renamed.WriteLockTimeout)) // obtain write lock
{
throw new LockObtainFailedException("Index locked for write: " + WriteLock);
}
bool success = false;
try
{
OpenMode_e? mode = Config_Renamed.OpenMode;
bool create;
if (mode == OpenMode_e.CREATE)
{
create = true;
}
else if (mode == OpenMode_e.APPEND)
{
create = false;
}
else
{
// CREATE_OR_APPEND - create only if an index does not exist
create = !DirectoryReader.IndexExists(directory);
}
// If index is too old, reading the segments will throw
// IndexFormatTooOldException.
segmentInfos = new SegmentInfos();
bool initialIndexExists = true;
if (create)
{
// Try to read first. this is to allow create
// against an index that's currently open for
// searching. In this case we write the next
// segments_N file with no segments:
try
{
segmentInfos.Read(directory);
segmentInfos.Clear();
}
catch (IOException)
{
// Likely this means it's a fresh directory
initialIndexExists = false;
}
// Record that we have a change (zero out all
// segments) pending:
Changed();
}
else
{
segmentInfos.Read(directory);
IndexCommit commit = Config_Renamed.IndexCommit;
if (commit != null)
{
// Swap out all segments, but, keep metadata in
// SegmentInfos, like version & generation, to
// preserve write-once. this is important if
// readers are open against the future commit
// points.
if (commit.Directory != directory)
{
throw new System.ArgumentException("IndexCommit's directory doesn't match my directory");
}
SegmentInfos oldInfos = new SegmentInfos();
oldInfos.Read(directory, commit.SegmentsFileName);
segmentInfos.Replace(oldInfos);
Changed();
if (infoStream.IsEnabled("IW"))
{
infoStream.Message("IW", "init: loaded commit \"" + commit.SegmentsFileName + "\"");
}
}
}
RollbackSegments = segmentInfos.CreateBackupSegmentInfos();
// start with previous field numbers, but new FieldInfos
GlobalFieldNumberMap = FieldNumberMap;
Config_Renamed.FlushPolicy.Init(Config_Renamed);
DocWriter = new DocumentsWriter(this, Config_Renamed, directory);
eventQueue = DocWriter.EventQueue();
// Default deleter (for backwards compatibility) is
// KeepOnlyLastCommitDeleter:
lock (this)
{
Deleter = new IndexFileDeleter(directory, Config_Renamed.DelPolicy, segmentInfos, infoStream, this, initialIndexExists);
}
if (Deleter.StartingCommitDeleted)
{
// Deletion policy deleted the "head" commit point.
// We have to mark ourself as changed so that if we
// are closed w/o any further changes we write a new
// segments_N file.
Changed();
}
if (infoStream.IsEnabled("IW"))
{
infoStream.Message("IW", "init: create=" + create);
MessageState();
}
success = true;
}
finally
{
if (!success)
{
if (infoStream.IsEnabled("IW"))
{
infoStream.Message("IW", "init: hit exception on init; releasing write lock");
}
WriteLock.Release();
IOUtils.CloseWhileHandlingException(WriteLock);
WriteLock = null;
}
}
}
/// <summary>
/// Returns <code>true</code> iff the index in the named directory is
/// currently locked. </summary>
/// <param name="directory"> the directory to check for a lock </param>
/// <exception cref="IOException"> if there is a low-level IO error </exception>
public static bool IsLocked(Directory directory)
{
return directory.MakeLock(WRITE_LOCK_NAME).Locked;
}