chapter_5

Question 1

object-oriented style: components are _______

Answer 1

objects: data and associated operations

Question 2

object-oriented style: connectors are ________

Answer 2

messages and method invocations

Question 3

object-oriented style invariants: objects are responsible for

Answer 3

their internal representation integrity

Question 4

oo-style internal representation is _______

Answer 4

hidden from other objects

Question 5

oo-style advantages: “infinite malleability of”

Answer 5

object internals

Question 6

oo-style system decomposition _______

Answer 6

into sets of interacting agents

Question 7

disadvantages of object-oriented style (2)

Answer 7

objects must know identities of servers, side effects in object method invocations

Question 8

layered style: hierarchical system organization (2)

Answer 8

multi-level client server, each layer exposes an interafce (API) to be used by above layers

Question 9

layered style: each layer acts as a (2)

Answer 9

server: service provider to layers “above”, client: service consumer of layer(s) “below”

Question 10

layered style: connectors are _____

Answer 10

protocols of layer interaction. example: operating systems

Question 11

virtual machine style ______

Answer 11

results from fully opaque layers

Question 12

layered style advantages (5)

Answer 12

1. increasing abstraction levels 2. evolvability 3. changes in a layer affect at most the adjacent two layers (resuse) 4. different implementations of layer are allowed as long as interface is preserved 5. standardized layer interfaces for libraries and frameworks

Question 13

layered style disadvantages (2)

Answer 13

disadvantages (not universally applicable, performance), layers may have to be skipped (determining the correct abstraction level)

Question 14

client-server style (4)

Answer 14

components are clients and servers, servers do not know number or identities of clients, clients know server’s identity, connects are RPC-based network interaction protocols.

Question 15

data-flow style: batch sequential (3)

Answer 15

batch sequential separate programs are executed in order; data is passed as an aggregate from one program to the next. connectors: “the human hand” carryign tpaes between the programs, aka “sneaker-net”, data elements: explicity aggregate elements passed from one component to the next upon completion of the producing program’s execution.

Question 16

data-flow styles: typical uses ______

Answer 16

transaction processing in financial systems. “the granddaddy of styles”

Question 17

pipe and filter style: components are filters (2)

Answer 17

transform input data streams into output data streams, possibly incremental production of output

Question 18

pipe and filter style: connects are _____

Answer 18

pipes: conduits for data streams

Question 19

pipe and filter style: style invariants (2)

Answer 19

filters are independent( no shared state), filter has no knowledge of up or down-stream filters

Question 20

pipe and filter style example (4)

Answer 20

unix shell, signal processing, distributed systems, parallel programming

Question 21

pipe and filter variations (3)

Answer 21

pipelines -linear sequences of filters, bounded pipes -limited amount of data on a pipe, typed pipes -data strongly typed

Question 22

pipe and filter advantages (4)

Answer 22

system behavior is a cuccession of component behaviors, filter addition, replacement, and resuse (possible to hook any two filters together), certain analyses (throughput, latency, deadlock), concurrent execution

Question 23

pipe and filter disadvantages (3)

Answer 23

batach organization of processing, interactive applications, lowest common denominator on data transmission

Question 24

blackboard style: two kinds of components

Answer 24

central data structure - blackboard, components oeprating on the blackboard

Question 25

blackboard style: system control is ______

Answer 25

entirely driven by the blackboard state

Question 26

blackboard style: examples (3)

Answer 26

typically used for AI systems, integrated software environments (interlisp), compiler architecture

Question 27

rule based style:

Answer 27

interference engine parses user input and determines whether it is a fact/rule or a query. if it is a fact/rule, it adds this entry to the knowledge base. otherwise it queries the knowledge base for applicable rules and attemps to resolve the query.