ostore.read
Class BytesReadReq

java.lang.Object
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  +--ostore.read.ReadReq
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        +--ostore.read.BytesReadReq

All Implemented Interfaces:

QueueElementIF, QuickSerializable

public class BytesReadReq

extends ReadReq

Events sent from the ReplicaStage to the ReadStage requesting the latter to read a portion of a DataObject and return the bytes read.

Version:

$Id: BytesReadReq.java,v 1.23 2002/07/29 18:48:53 geels Exp $

Author:

Dennis Geels

Field Summary

protected SortedMap

spare_blocks A VID->block map containing blocks that the ReadStage may use in addition to those found in the memory cache, or null if none.

Fields inherited from class ostore.read.ReadReq

digest, FAIL, fault_mode, FETCH_ALL, PARTIAL, sel, target, tree_id

Constructor Summary

BytesReadReq(InputBuffer buffer)
Constructs a BytesReadReq from its serialized form.

BytesReadReq(VID target, SecureHash tree_id, Selection sel, byte fault_mode, Map spare_blocks)
Constructs a new BytesReadReq.

Method Summary

Map	get_spares() Returns the VID->block map that contains extra blocks that the ReadStage may use in addition to those found in the memory cache.
void	serialize(OutputBuffer buffer) Add the object to the buffer.

Methods inherited from class ostore.read.ReadReq

get_digest, get_fault_mode, get_selection, get_seq_num, get_target, get_tree_id, hashCode, toString

Methods inherited from class java.lang.Object

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

Field Detail

spare_blocks

protected SortedMap spare_blocks

A VID->block map containing blocks that the ReadStage may use in addition to those found in the memory cache, or null if none.

Presumably these blocks were returned with a SliceReadResp from a remote node. The ReadStage should verify any blocks used and insert them into the memory cache.

The hashCode of the request depends on its digest. Therefore we keep this map sorted, to ensure a deterministic serialization.

Constructor Detail

BytesReadReq

public BytesReadReq(VID target,
                    SecureHash tree_id,
                    Selection sel,
                    byte fault_mode,
                    Map spare_blocks)

Constructs a new BytesReadReq.

BytesReadReq

public BytesReadReq(InputBuffer buffer)
             throws QSException

Constructs a BytesReadReq from its serialized form.

Method Detail

get_spares

public Map get_spares()

Returns the VID->block map that contains extra blocks that the ReadStage may use in addition to those found in the memory cache.

serialize

public void serialize(OutputBuffer buffer)

Description copied from interface: QuickSerializable

Add the object to the buffer.

Specified by:

serialize in interface QuickSerializable

Overrides:

serialize in class ReadReq

Parameters:

buffer - the output buffer to add the object to