com.faunos.skwish.sys.filters
Class SubSegment

java.lang.Object
  com.faunos.skwish.Segment
      com.faunos.skwish.sys.filters.FilterSegment
          com.faunos.skwish.sys.filters.AppendProtectedFilterSegment
              com.faunos.skwish.sys.filters.SubSegment

All Implemented Interfaces:

Range

Direct Known Subclasses:

LiveSegManager.FixedSegment

public class SubSegment
extends AppendProtectedFilterSegment

A fixed-count view of an underlying segment. The entry count of this view remains frozen, even as entries are inserted in the underlying segment.

Author:

Babak Farhang

Field Summary

Fields inherited from class com.faunos.skwish.sys.filters.FilterSegment

inner

Fields inherited from class com.faunos.skwish.Segment

validator

Constructor Summary

SubSegment(Segment inner)
Creates an instance whose entry count is frozen at the current value of the underlying instance.

SubSegment(Segment inner, long size)

Method Summary

void	getEntry(long id, ByteBuffer out, ByteBuffer workBuffer) Returns the contents of the entry with the specified id.
FileChannel	getEntryChannel(long id) Returns the contents of the entry with the given id as a FileChannel, or null, if deleted.
long	getEntryCount() Returns the number of entries in this instance.
long	getEntrySize(long id, ByteBuffer workBuffer) Returns the size of the entry with the specified id.
long	getNextId() Returns the ID the entry will get on the next insertion.

Methods inherited from class com.faunos.skwish.sys.filters.AppendProtectedFilterSegment

insertEntry, insertEntry, killNext

Methods inherited from class com.faunos.skwish.sys.filters.FilterSegment

delete, getBaseId, getEntryPart, isReadOnly

Methods inherited from class com.faunos.skwish.Segment

contains, delete, delete, getEntry, getEntrySize, getEntryStream, hi, isDeleted, isDeleted, killNext, lo, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SubSegment

public SubSegment(Segment inner)

Creates an instance whose entry count is frozen at the current value of the underlying instance.

Parameters:

inner - the underlying segment

SubSegment

public SubSegment(Segment inner,
                  long size)

Method Detail

getEntry

public final void getEntry(long id,
                           ByteBuffer out,
                           ByteBuffer workBuffer)
                    throws IOException

Description copied from class: Segment

Returns the contents of the entry with the specified id. If the entry is deleted, the method returns without modifying the out buffer.

Overrides:

getEntry in class FilterSegment

out - the buffer into which the contents are written. Its remaining bytes must be large enough; o.w., an exception is raised.

workBuffer - a work buffer used internally to read offsets. The minimum capacity of this work buffer must be 16

Throws:

IOException

getEntryChannel

public final FileChannel getEntryChannel(long id)
                                  throws IOException

Description copied from class: Segment

Returns the contents of the entry with the given id as a FileChannel, or null, if deleted. The returned channel is positioned at zero and is read-only.

Overrides:

getEntryChannel in class FilterSegment

Throws:

IOException

getEntryCount

public final long getEntryCount()

Description copied from class: Segment

Returns the number of entries in this instance.

Overrides:

getEntryCount in class FilterSegment

getEntrySize

public final long getEntrySize(long id,
                               ByteBuffer workBuffer)
                        throws IOException

Description copied from class: Segment

Returns the size of the entry with the specified id. A work buffer with a minimum size of 16 must be passed in.

Overrides:

getEntrySize in class FilterSegment

Returns:

the size of the entry if present; -1, if deleted.

Throws:

IOException

getNextId

public final long getNextId()

Description copied from class: Segment

Returns the ID the entry will get on the next insertion.

Overrides:

getNextId in class FilterSegment

See Also:

ID invariants