FaTC2: An Object-Oriented Framework for Developing Fault-Tolerant - - PowerPoint PPT Presentation
Institute of Computing UNICAMP - Brazil FaTC2: An Object-Oriented Framework for Developing Fault-Tolerant Component-Based Systems Fernando J. Castor de Lima Filho Paulo Asterio de C. Guerra Ceclia Mary F. Rubira {fernando, asterio,
1
Fernando J. Castor de Lima Filho Paulo Asterio de C. Guerra Cecília Mary F. Rubira
{fernando, asterio, cmrubira}@ic.unicamp.br ICSE 2003 – Workshop on Software Architectures for Dependable Systems
2
Few assumptions can be made about the level of
An architectural approach is required
3
Traditional EHSs lack support for attaching exception
handlers to architectural elements (components, connectors, configurations)
In an architecture, exception propagation does not
necessarily follow the method invocation chain
An architectural-level EHS should support the attachment of
handlers to components without requiring modifications to them
4
Based on the concept of idealised fault-tolerant
5
Normal Activity Abnormal Activity
Recovery Local Exceptions Service Requests Normal Responses Service Requests Normal Responses Interface Exceptions Interface Exceptions Failure Exceptions Failure Exceptions
6
Integration of heterogeneous off-the-shelf components
Layered Elements in an architecture communicate by means of
asynchronous messages
Each component may have its own control thread
ArchStudio C2.FW framework
7
Component 3
Connector 1
Component 4 Component 2 Component 1 Requests Notifications
Connector 2
8
C2.FW lacks support for fault tolerance.
Exception Handling System
9
10
NormalActivity
iC2C_top iC2C_internal
AbnormalActivity
iC2C_bottom Normal behavior & Error detection Error diagnosis & recovery
11
NormalActivity component: normal behavior and
AbnormalActivity component: error treatment
Developers focus on implementing the normal and
Abstracts the interaction protocol
12
NormalActivity
iC2C_top iC2C_internal
AbnormalActivity
iC2C_bottom Provided by the application developer
13
NormalActivity
iC2C_top iC2C_internal
AbnormalActivity
iC2C_bottom Provided by FaTC2
14
Separates exception handlers from normal
Handlers may be attachted to components,
Exception propagation according to the execution
15
16
17
iC2C_top iC2C_internal
AbnormalActivity
iC2C_bottom External exception handlers Internal exception handlers Normal behavior
18
iC2C_top iC2C_internal
AbnormalActivity
iC2C_bottom A C2 configuration Exception handlers for the whole configuration
19
External iC2C
AbnormalActivity (...) (...)
Normal Activity
20
External iC2C
AbnormalActivity (...) (...)
Service Request Normal Activity
21
External iC2C
AbnormalActivity (...) (...)
Normal Activity Exception Raised
22
External iC2C
AbnormalActivity (...) (...)
Normal Activity Unable to handle exception. Re-raising
23
External iC2C
AbnormalActivity (...) (...)
Normal Activity Unable to handle exception. Re-raising
24
External iC2C
AbnormalActivity (...) (...)
Normal Activity Exception handled successfully. Returning to normal Green iC2C receives return-to-normal request
25
External iC2C
AbnormalActivity (...) (...)
Normal Activity The NormalActivity component of the green iC2C handles the request
26
(...) Original (C2.FW) Extension
FaTC2
AbstractC2DelegateBrick IC2CBottomConnector IC2CTopConnector IC2CInternalConnector INormalActivityComponent <<Interface>> IAbnormalActivityComponent <<Interface>> AbstractNormalActivityComponent IC2CBrick AbstractAbnormalActivityComponent DelegateBrick <<Interface>> IC2C Component <<Interface>> IC2CCompositeBrick
27
Definition of an architectural-level EHS for
Construction of a reusable implementation for this
Extension of the C2.FW framework with forward
28
Hierarchical handler search Attachment of handlers to arbitrary
29
30