ostore.read
Class ReplicaReadReq

java.lang.Object
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  +--ostore.replica.ReplicaReq
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        +--ostore.read.ReplicaReadReq

All Implemented Interfaces:

QueueElementIF, QuickSerializable

Direct Known Subclasses:

ReplicaBytesReadReq, ReplicaMetadataReadReq, ReplicaSliceReadReq, ReplicaVersionQueryReq

public abstract class ReplicaReadReq

extends ReplicaReq

Events sent from the ClientStage to the ReplicaStage requesting the latter to read a portion of a Replica.

Version:

$Id: ReplicaReadReq.java,v 1.20 2002/07/29 18:48:53 geels Exp $

Author:

Dennis Geels

Field Summary

static byte	FAIL A value for fault_mode instructing the ReplicaStage to give up completely.
protected byte	fault_mode Specifies what the ReplicaStage should do if any required blocks from the DataObject are missing from the memory cache.
static byte	FETCH_ALL A value for fault_mode instructing the ReplicaStage to fetch missing blocks through the block manager (memory cache).
static byte	INTERIM A value for fault_mode instructing the ReplicaStage to return as much data as possible immediately, as with PARTIAL, but continue to read the remainder of the Selection automatically, as with FETCH_ALL.
static byte	PARTIAL A value for fault_mode instructing the ReplicaStage to read as much as possible and include in its response a Selection describing the portion of the DataObject which it could not find locally.
protected Selection	sel The portion of the DataObject to read, or null if none.
protected VersionPredicate	version_pred A predicate specifying which version(s) of the Replica (a DataObject) to read.

Fields inherited from class ostore.replica.ReplicaReq

digest, local, target

Constructor Summary

protected	ReplicaReadReq(InputBuffer buffer) Constructs a ReplicaReadReq from its serialized form.
protected	ReplicaReadReq(SecureHash target, VersionPredicate version_pred, Selection sel, byte fault_mode) Constructs a new ReplicaReadReq.

Method Summary

byte	get_fault_mode() Returns the code for the fault mode.
VersionPredicate	get_predicate() Returns the predicate specifying which version(s) of the Replica (a DataObject) to read.
Selection	get_selection() Returns the Selection describing the read.
void	serialize(OutputBuffer buffer) Add the object to the buffer.
String	toString() Returns a human-readable representation of this ReplicaReaqReq.

Methods inherited from class ostore.replica.ReplicaReq

get_digest, get_seq_num, get_target, hashCode, is_local

Methods inherited from class java.lang.Object

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

Field Detail

FAIL

public static final byte FAIL

A value for fault_mode instructing the ReplicaStage to give up completely.

See Also:

Constant Field Values

FETCH_ALL

public static final byte FETCH_ALL

A value for fault_mode instructing the ReplicaStage to fetch missing blocks through the block manager (memory cache).

See Also:

Constant Field Values

PARTIAL

public static final byte PARTIAL

A value for fault_mode instructing the ReplicaStage to read as much as possible and include in its response a Selection describing the portion of the DataObject which it could not find locally.

See Also:

Constant Field Values

INTERIM

public static final byte INTERIM

A value for fault_mode instructing the ReplicaStage to return as much data as possible immediately, as with PARTIAL, but continue to read the remainder of the Selection automatically, as with FETCH_ALL. The remainder will be returned in a second ReplicaReadResp.

See Also:

Constant Field Values

version_pred

protected VersionPredicate version_pred

A predicate specifying which version(s) of the Replica (a DataObject) to read.

sel

protected Selection sel

The portion of the DataObject to read, or null if none. Should only be null for ReplicaMetadataReadReqs.

fault_mode

protected byte fault_mode

Specifies what the ReplicaStage should do if any required blocks from the DataObject are missing from the memory cache.

Constructor Detail

ReplicaReadReq

protected ReplicaReadReq(SecureHash target,
                         VersionPredicate version_pred,
                         Selection sel,
                         byte fault_mode)

Constructs a new ReplicaReadReq.

ReplicaReadReq

protected ReplicaReadReq(InputBuffer buffer)
                  throws QSException

Constructs a ReplicaReadReq from its serialized form.

Method Detail

get_predicate

public VersionPredicate get_predicate()

Returns the predicate specifying which version(s) of the Replica (a DataObject) to read.

get_selection

public Selection get_selection()

Returns the Selection describing the read.

get_fault_mode

public byte get_fault_mode()

Returns the code for the fault mode.

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 ReplicaReq

Parameters:

buffer - the output buffer to add the object to

toString

public String toString()

Returns a human-readable representation of this ReplicaReaqReq.

Overrides:

toString in class ReplicaReq