/// <summary>Constructor</summary>
/// <param name="register">the block register, which is called when the block is closed.
/// </param>
/// <param name="wbs">The writable compression block state.</param>
internal BlockAppender(Writer _enclosing, BCFile.Writer.BlockRegister register, BCFile.Writer.WBlockState
wbs)
: base(wbs.GetOutputStream())
{
this._enclosing = _enclosing;
this.blockRegister = register;
this.wBlkState = wbs;
}
/// <summary>
/// Create a Data Block and obtain an output stream for adding data into the
/// block.
/// </summary>
/// <remarks>
/// Create a Data Block and obtain an output stream for adding data into the
/// block. There can only be one BlockAppender stream active at any time.
/// Data Blocks may not be created after the first Meta Blocks. The caller
/// must call BlockAppender.close() to conclude the block creation.
/// </remarks>
/// <returns>The BlockAppender stream</returns>
/// <exception cref="System.IO.IOException"/>
public virtual BCFile.Writer.BlockAppender PrepareDataBlock()
{
if (blkInProgress == true)
{
throw new InvalidOperationException("Cannot create Data Block until previous block is closed."
);
}
if (metaBlkSeen == true)
{
throw new InvalidOperationException("Cannot create Data Block after Meta Blocks."
);
}
BCFile.Writer.DataBlockRegister dbr = new BCFile.Writer.DataBlockRegister(this);
BCFile.Writer.WBlockState wbs = new BCFile.Writer.WBlockState(GetDefaultCompressionAlgorithm
(), @out, fsOutputBuffer, conf);
BCFile.Writer.BlockAppender ba = new BCFile.Writer.BlockAppender(this, dbr, wbs);
blkInProgress = true;
return(ba);
}
/// <exception cref="System.IO.IOException"/>
/// <exception cref="Org.Apache.Hadoop.IO.File.Tfile.MetaBlockAlreadyExists"/>
private BCFile.Writer.BlockAppender PrepareMetaBlock(string name, Compression.Algorithm
compressAlgo)
{
if (blkInProgress == true)
{
throw new InvalidOperationException("Cannot create Meta Block until previous block is closed."
);
}
if (metaIndex.GetMetaByName(name) != null)
{
throw new MetaBlockAlreadyExists("name=" + name);
}
BCFile.Writer.MetaBlockRegister mbr = new BCFile.Writer.MetaBlockRegister(this, name
, compressAlgo);
BCFile.Writer.WBlockState wbs = new BCFile.Writer.WBlockState(compressAlgo, @out,
fsOutputBuffer, conf);
BCFile.Writer.BlockAppender ba = new BCFile.Writer.BlockAppender(this, mbr, wbs);
blkInProgress = true;
metaBlkSeen = true;
return(ba);
}
