uk.ac.starlink.table.storage
Class LimitByteStore

java.lang.Object
  extended by uk.ac.starlink.table.storage.LimitByteStore
All Implemented Interfaces:
ByteStore

public class LimitByteStore
extends Object
implements ByteStore

ByteStore wrapper class which will throw an IOException during writing if an attempt is made to store more than a fixed number of bytes.

Since:
29 Mar 2011

Constructor Summary
LimitByteStore(ByteStore base, long limit)
          Constructor.
 
Method Summary
 void close()
          Tidies up.
 void copy(OutputStream out)
          Takes all the data written so far into this store's sink stream and copies it to a destination stream.
 long getLength()
          Returns the number of bytes currently stored in this object.
 OutputStream getOutputStream()
          Returns an output stream which can be used to write to the store.
 ByteBuffer[] toByteBuffers()
          Returns an array of byte buffers containing the bytes written to this store.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LimitByteStore

public LimitByteStore(ByteStore base,
                      long limit)
Constructor.

Parameters:
base - base byte store
limit - maximum capacity of this store in bytes
Method Detail

getOutputStream

public OutputStream getOutputStream()
Description copied from interface: ByteStore
Returns an output stream which can be used to write to the store. May be called multiple times; always returns the same object. Note that this is not in general buffered - it is the responsibility of the user to take steps like wrapping it in a BufferedOutputStream for efficiency if required.

Specified by:
getOutputStream in interface ByteStore
Returns:
data sink stream

getLength

public long getLength()
Description copied from interface: ByteStore
Returns the number of bytes currently stored in this object.

Specified by:
getLength in interface ByteStore
Returns:
byte count

copy

public void copy(OutputStream out)
          throws IOException
Description copied from interface: ByteStore
Takes all the data written so far into this store's sink stream and copies it to a destination stream. The output stream is not closed.

Specified by:
copy in interface ByteStore
Parameters:
out - data destination stream
Throws:
IOException

toByteBuffers

public ByteBuffer[] toByteBuffers()
                           throws IOException
Description copied from interface: ByteStore
Returns an array of byte buffers containing the bytes written to this store. The stored bytes are all of the bytes from the first buffer in the returned array, followed by all in the second, etc. In many cases the returned array will, and probably should, contain a single buffer, but if the written byte count exceeds Integer.MAX_VALUE, more than one will be required. The limit of each buffer indicates the number of bytes it contains.

Usual usage will be to write all data, then call this method once; this model may affect implementation decisions about efficiency.

Specified by:
toByteBuffers in interface ByteStore
Returns:
byte buffer containing bytes written
Throws:
IOException - if there is an I/O error

close

public void close()
Description copied from interface: ByteStore
Tidies up. Should be called when the data in this object is no longer required. This object may no longer be usable following a call to this method.

Specified by:
close in interface ByteStore

Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved.