During this activity:
This activity helps students develop the following skills, values and attitudes: ability to analyze and synthesize, capacity for identifying and solving problems, and efficient use of computer systems.
This activity can be developed individually or in pairs.
Create a folder called adapter
. Inside this folder, create three files called: simple_queue.rb
, queue_adapter.rb
, and adapter_test.rb
.
All three Ruby source files must start with a comment containing title, date, and the authors' personal information. For example:
# Adapter Pattern # Date: 02-Mar-2016 # Authors: # A00456654 Thursday Rubinstein # A01160611 Anthony Stark
The content of the file simple_queue.rb
is as follows:
# File: simple_queue.rb # IMPORTANT: Do not modify the following class in any way! class SimpleQueue def initialize @info =[] end def insert(x) @info.push(x) self end def remove if empty? raise "Can't remove if queue is empty" else @info.shift end end def empty? @info.empty? end def size @info.size end def inspect @info.inspect end end
The SimpleQueue
class contains a First-In First-Out (FIFO) data structure that implements the following methods:
Method Signature | Description |
---|---|
insert(x)
|
Inserts x at the back of this queue. Returns this queue. |
remove
|
Removes and returns the element at the front of this queue. Raises an exception if this queue happens to be empty. |
empty?
|
Returns true if this queue is empty, otherwise returns false .
|
size
|
Returns the number of elements currently stored in this queue. |
Write an adapter class called QueueAdapter
(place it in the file called queue_adapter.rb
) that makes a SimpleQueue
instance (as implemented above) behave like a Last-In First-Out (LIFO) stack with the following interface:
Method Signature | Description |
---|---|
initialize(q)
|
Initializes a new stack, using q as the adaptee. |
push(x)
|
Inserts x at the top of this stack. Returns this stack. |
pop
|
Returns nil if this stack is empty, otherwise removes and returns its top element.
|
peek
|
Returns nil if this stack is empty, otherwise returns its top element without removing it.
|
empty?
|
Returns true if this stack is empty, otherwise returns false.
|
size
|
Returns the number of elements currently stored in this stack. |
QueueAdapter
class. Place the test class in the adapter_test.rb
source file.
# File: adapter_test.rb require 'minitest/autorun' require 'simple_queue' require 'queue_adapter' class QueueAdapterTest < Minitest::Test def test_queue_adapter q = SimpleQueue.new qa = QueueAdapter.new(q) assert q.empty? assert qa.empty? assert_nil qa.pop assert_same qa, qa.push("Foo") assert_equal "Foo", qa.peek refute q.empty? refute qa.empty? assert_same qa, qa.push("Bar") assert_equal "Bar", qa.peek assert_same qa, qa.push("Baz").push("Quux") assert_equal 4, q.size assert_equal 4, qa.size assert_equal "Quux", qa.peek assert_equal "Quux", qa.pop assert_equal "Baz", qa.peek assert_equal "Baz", qa.pop assert_equal "Bar", qa.peek assert_equal "Bar", qa.pop assert_equal "Foo", qa.peek assert_same qa, qa.push("Goo") assert_equal "Goo", qa.peek assert_equal "Goo", qa.pop assert_equal "Foo", qa.peek assert_equal 1, qa.size assert_equal "Foo", qa.pop assert_nil qa.peek assert_nil qa.pop assert q.empty? assert qa.empty? assert_equal 0, q.size assert_equal 0, qa.size end end
Create a compressed tarball file with the full contents of the adapter
directory. Call this file adapter.tgz
. From a terminal, you can use the following command to create this file (make sure to run it at the same level where the adapter
folder resides):
tar czf adapter.tgz adapter
To deliver the adapter.tgz
file, please provide the following information:
Due date is Wednesday, March 2.