CSC/ECE 517 Fall 2011/ch7 7d rt - Revision history

Tfgregor: /* Example */

2011-12-01T01:15:26Z

Example

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	====Example====		====Example====
	An example of class approaching '''The Blob''' that may be familiar to many students this semester is the [http://wikis.lib.ncsu.edu/index.php/Expertiza Expertiza] Project's assignment model.<ref name="expertiza" /> The assignment model in Expertiza does not encapsulate the majority of functionality in the entire application, but it is out of proportion with most of the other classes, and it does include functionality that should be in some other classes.<ref name="fall2011_oss" /> One of the Open-Source Software projects for this semester is to correct some of these problems. The project assignment contains the following notes:<ref name="fall2011_oss" />		An example of a class approaching '''The Blob''' that may be familiar to many students this semester is the [http://wikis.lib.ncsu.edu/index.php/Expertiza Expertiza] Project's assignment model.<ref name="expertiza" /> The assignment model in Expertiza does not encapsulate the majority of functionality in the entire application, but it is out of proportion with most of the other classes, and it does include functionality that should be in some other classes.<ref name="fall2011_oss" /> One of the Open-Source Software projects for this semester is to correct some of these problems. The project assignment contains the following notes:<ref name="fall2011_oss" />

	<blockquote>[The assignment model] contains functionality for adding and removing participants for this assignment, which should really be in a participant class, for assigning reviewers, which should probably be in a reviewer class, and for computing the maximum score possible on a questionnaire. Functions like compute_scores, and candidate_topics_to_review, among others, should be moved to other classes.</blockquote>		<blockquote>"[The assignment model] contains functionality for adding and removing participants for this assignment, which should really be in a participant class, for assigning reviewers, which should probably be in a reviewer class, and for computing the maximum score possible on a questionnaire. Functions like compute_scores, and candidate_topics_to_review, among others, should be moved to other classes."</blockquote>

	These notes describe some of the excessive functionality of assignment.rb. It also suggests some other classes that would be more appropriate locations for some functionalities. If these modifications are made, then the assignment model will be of a more manageable size, and will not be in danger of becoming '''The Blob'''.		These notes describe some of the excessive functionality of assignment.rb. It also suggests some other classes that would be more appropriate locations for some functionalities. If these modifications are made, then the assignment model will be of a more manageable size, and will not be in danger of becoming '''The Blob'''.

	===Golden Hammer===		===Golden Hammer===

Tfgregor: /* Example */

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Example

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	toll booth operator, token processor, cross arm, change processor, etc. */		toll booth operator, token processor, cross arm, change processor, etc. */

	Obviously, a tollbooth is not a queue, but more appropriately, ~~'''~~has a~~'''~~ queue. Hence, our toll booth class should be created to contain a queue to model the line of cars.		Obviously, a tollbooth is not a queue, but more appropriately, "has a" queue. Hence, our toll booth class should be created to contain a queue to model the line of cars.

	public class TollBooth		public class TollBooth

Tfgregor: /* Example */

2011-12-01T01:11:29Z

Example

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	toll booth operator, token processor, cross arm, change processor, etc. */		toll booth operator, token processor, cross arm, change processor, etc. */

	Obviously, a tollbooth is not a queue, but more appropriately, has a queue. Hence, our toll booth class should be created to contain a queue to model the line of cars.		Obviously, a tollbooth is not a queue, but more appropriately, '''has a''' queue. Hence, our toll booth class should be created to contain a queue to model the line of cars.

	public class TollBooth		public class TollBooth

Rbjeffer at 00:57, 30 November 2011

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	====Example====		====Example====

	When [http://en.wikipedia.org/wiki/Automated_teller_machine Automated Teller Machines (ATMs)] were popularized in the 1970s, they were often designed using [http://en.wikipedia.org/wiki/Computer_terminal Dumb Terminals], a contemporary computer technology. In the 1990s and 2000s, many banks began replacing their aging ATMs with more modern ones that were physically more difficult to break into. Many of these banks have not changed the communication protocols that the ATMs use to conduct transactions with the bank's servers or mainframe, because weaknesses in the protocol or cryptography is not the cause of most ATM fraud.<ref name="crypto" /> As a result, many banks designed new ATMs that were required to somehow use the existing technology: encrypted dumb terminal sessions. The majority of these systems that have been deployed used a familiar '''Golden Hammer''' to do this: [http://en.wikipedia.org/wiki/Terminal_emulator Terminal Emulator] software installed on a variant of the [http://en.wikipedia.org/wiki/Microsoft_windows Microsoft Windows] operating system.<ref name="wikipedia_atm" />		When [http://en.wikipedia.org/wiki/Automated_teller_machine Automated Teller Machines (ATMs)] were popularized in the 1970s, they were often designed using [http://en.wikipedia.org/wiki/Computer_terminal Dumb Terminals], a contemporary computer technology. In the 1990s and 2000s, many banks began replacing their aging ATMs with more modern ones that were physically more difficult to break into. Many of these banks have not changed the communication protocols that the ATMs use to conduct transactions with the bank's servers or mainframe, because weaknesses in the protocol or cryptography is not the cause of most ATM fraud.<ref name="crypto" /> As a result, many banks designed new ATMs that were required to somehow use the existing technology: encrypted dumb terminal sessions. The majority of these systems that have been deployed used a familiar '''Golden Hammer''' to do this: [http://en.wikipedia.org/wiki/Terminal_emulator Terminal Emulator] software installed on a variant of the [http://en.wikipedia.org/wiki/Microsoft_windows Microsoft Windows] operating system.<ref name="wikipedia_atm" /> This design decision has several negative effects, including:
			* Increased unit cost of ATMs, because each one must have a licensed copy of a commercial operating system
			* Concerns about the reliability and trustworthiness of the underlying ATM software<ref name=windowsatm />

	==Conclusion==		==Conclusion==

	In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes. ~~This design decision has several negative effects, including:~~		In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.
	* Increased unit cost of ATMs, because each one must have a licensed copy of a commercial operating system
	* Concerns about the reliability and trustworthiness of the underlying ATM software<ref name=windowsatm />

	==Resources==		==Resources==

Rbjeffer at 00:55, 30 November 2011

2011-11-30T00:55:35Z

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	In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes. This design decision has several negative effects, including:		In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes. This design decision has several negative effects, including:
	+ Increased unit cost of ATMs, because each one must have a licensed copy of a commercial operating system		* Increased unit cost of ATMs, because each one must have a licensed copy of a commercial operating system
	+ Concerns about the reliability and trustworthiness of the underlying ATM software<ref name=windowsatm />		* Concerns about the reliability and trustworthiness of the underlying ATM software<ref name=windowsatm />

	==Resources==		==Resources==

Rbjeffer at 00:55, 30 November 2011

2011-11-30T00:55:05Z

← Older revision		Revision as of 00:55, 30 November 2011
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	====Example====		====Example====

	When [http://en.wikipedia.org/wiki/Automated_teller_machine Automated Teller Machines (ATMs)] were popularized in the 1970s, they were often designed using [http://en.wikipedia.org/wiki/Computer_terminal Dumb Terminals], a contemporary computer technology. In the 1990s and 2000s, many banks began replacing their aging ATMs with more modern ones that were physically more difficult to break into. Many of these banks have not changed the communication protocols that the ATMs use to conduct transactions with the bank's servers or mainframe, because weaknesses in the protocol or cryptography is not the cause of most ATM fraud.<ref name="crypto" /> As a result, many banks designed new ATMs that were required to somehow use the existing technology: encrypted dumb terminal sessions. The majority of these systems that have been deployed used a familiar '''Golden Hammer''' to do this: [http://en.wikipedia.org/wiki/Terminal_emulator Terminal Emulator] software installed on a variant of the [http://en.wikipedia.org/wiki/Microsoft_windows Microsoft Windows] operating system.		When [http://en.wikipedia.org/wiki/Automated_teller_machine Automated Teller Machines (ATMs)] were popularized in the 1970s, they were often designed using [http://en.wikipedia.org/wiki/Computer_terminal Dumb Terminals], a contemporary computer technology. In the 1990s and 2000s, many banks began replacing their aging ATMs with more modern ones that were physically more difficult to break into. Many of these banks have not changed the communication protocols that the ATMs use to conduct transactions with the bank's servers or mainframe, because weaknesses in the protocol or cryptography is not the cause of most ATM fraud.<ref name="crypto" /> As a result, many banks designed new ATMs that were required to somehow use the existing technology: encrypted dumb terminal sessions. The majority of these systems that have been deployed used a familiar '''Golden Hammer''' to do this: [http://en.wikipedia.org/wiki/Terminal_emulator Terminal Emulator] software installed on a variant of the [http://en.wikipedia.org/wiki/Microsoft_windows Microsoft Windows] operating system.<ref name="wikipedia_atm" />

	==Conclusion==		==Conclusion==

	In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.		In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes. This design decision has several negative effects, including:
			+ Increased unit cost of ATMs, because each one must have a licensed copy of a commercial operating system
			+ Concerns about the reliability and trustworthiness of the underlying ATM software<ref name=windowsatm />

	==Resources==		==Resources==
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	<ref name = fall2011_oss> [https://docs.google.com/a/ncsu.edu/document/d/1zZ-a_tkLGrbYJbG-2QBCRqe_Y9XLR4AZMH0rc6KvrYU/edit?hl=en_US CSC/ECE517 Fall 2011 OSS Projects in Expertiza] </ref>		<ref name = fall2011_oss> [https://docs.google.com/a/ncsu.edu/document/d/1zZ-a_tkLGrbYJbG-2QBCRqe_Y9XLR4AZMH0rc6KvrYU/edit?hl=en_US CSC/ECE517 Fall 2011 OSS Projects in Expertiza] </ref>
	<ref name = crypto> Anderson, R. 1993. Why cryptosystems fail. In Proceedings of the 1st ACM Conference on Computer and Communications Security (Fairfax, Virginia, United States, November 03 - 05, 1993). CCS '93 [http://www.cl.cam.ac.uk/~rja14/Papers/wcf.pdf]</ref>		<ref name = crypto> Anderson, R. 1993. Why cryptosystems fail. In Proceedings of the 1st ACM Conference on Computer and Communications Security (Fairfax, Virginia, United States, November 03 - 05, 1993). CCS '93 [http://www.cl.cam.ac.uk/~rja14/Papers/wcf.pdf]</ref>
			<ref name = wikipedia_atm> [http://en.wikipedia.org/wiki/Automatic_Teller_Machine http://en.wikipedia.org/wiki/Automatic_Teller_Machine]</ref>
			<ref name = windowsatm> [http://www.technewsworld.com/story/32350.html "Technology News: Security: Windows Cash-Machine Worm Generates Concern". Technewsworld.com] </ref>
	</ref>		</ref>
	</references>		</references>

Rbjeffer at 00:46, 30 November 2011

2011-11-30T00:46:53Z

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	The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />		The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />

			====Example====

			When [http://en.wikipedia.org/wiki/Automated_teller_machine Automated Teller Machines (ATMs)] were popularized in the 1970s, they were often designed using [http://en.wikipedia.org/wiki/Computer_terminal Dumb Terminals], a contemporary computer technology. In the 1990s and 2000s, many banks began replacing their aging ATMs with more modern ones that were physically more difficult to break into. Many of these banks have not changed the communication protocols that the ATMs use to conduct transactions with the bank's servers or mainframe, because weaknesses in the protocol or cryptography is not the cause of most ATM fraud.<ref name="crypto" /> As a result, many banks designed new ATMs that were required to somehow use the existing technology: encrypted dumb terminal sessions. The majority of these systems that have been deployed used a familiar '''Golden Hammer''' to do this: [http://en.wikipedia.org/wiki/Terminal_emulator Terminal Emulator] software installed on a variant of the [http://en.wikipedia.org/wiki/Microsoft_windows Microsoft Windows] operating system.

	==Conclusion==		==Conclusion==

	In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.		In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.


	==Resources==		==Resources==
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	<ref name = expertiza> [http://wikis.lib.ncsu.edu/index.php/Expertiza Expertiza - Reusable learning objects through peer review] </ref>		<ref name = expertiza> [http://wikis.lib.ncsu.edu/index.php/Expertiza Expertiza - Reusable learning objects through peer review] </ref>
	<ref name = fall2011_oss> [https://docs.google.com/a/ncsu.edu/document/d/1zZ-a_tkLGrbYJbG-2QBCRqe_Y9XLR4AZMH0rc6KvrYU/edit?hl=en_US CSC/ECE517 Fall 2011 OSS Projects in Expertiza] </ref>		<ref name = fall2011_oss> [https://docs.google.com/a/ncsu.edu/document/d/1zZ-a_tkLGrbYJbG-2QBCRqe_Y9XLR4AZMH0rc6KvrYU/edit?hl=en_US CSC/ECE517 Fall 2011 OSS Projects in Expertiza] </ref>
			<ref name = crypto> Anderson, R. 1993. Why cryptosystems fail. In Proceedings of the 1st ACM Conference on Computer and Communications Security (Fairfax, Virginia, United States, November 03 - 05, 1993). CCS '93 [http://www.cl.cam.ac.uk/~rja14/Papers/wcf.pdf]</ref>
	</ref>		</ref>
	</references>		</references>

Rbjeffer at 00:20, 30 November 2011

2011-11-30T00:20:16Z

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	<references>		<references>
	<ref name = koenig> Koenig, Andrew (March/April 1995). "Patterns and Antipatterns". Journal of Object-Oriented Programming 8 (1): 46–48.; was later re-printed in the: Rising, Linda (1998). [http://books.google.com/?id=HBAuixGMYWEC&pg=PT1&dq=0-521-64818-1 The patterns handbook: techniques, strategies, and applications]. Cambridge, U.K.: Cambridge University Press. p. 387. </ref>		<ref name = koenig> Koenig, Andrew (March/April 1995). "Patterns and Antipatterns". Journal of Object-Oriented Programming 8 (1): 46–48.; was later re-printed in the: Rising, Linda (1998). [http://books.google.com/?id=HBAuixGMYWEC&pg=PT1&dq=0-521-64818-1 The patterns handbook: techniques, strategies, and applications]. Cambridge, U.K.: Cambridge University Press. p. 387. </ref>
	<ref name = gof> [http://en.wikipedia.org/wiki/Design_Patterns_%28book%29 Design Patterns] by Gang of Four</ref>		<ref name = gof> [http://en.wikipedia.org/wiki/Design_Patterns_%28book%29 Design Patterns] by the Gang of Four</ref>
	<ref name = ap> Brown, William J.; Raphael C. Malveau, Hays W. "Skip" McCormick, Thomas J. Mowbray, Theresa Hudson (ed) (1998). [http://www.antipatterns.com/AntiPatterns/Welcome.html ''AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis''. ]</ref>		<ref name = ap> Brown, William J.; Raphael C. Malveau, Hays W. "Skip" McCormick, Thomas J. Mowbray, Theresa Hudson (ed) (1998). [http://www.antipatterns.com/AntiPatterns/Welcome.html ''AntiPatterns: Refactoring Software, Architectures, and Projects in Crisis''. ]</ref>
	<ref name = sourcemaking_tb> [http://sourcemaking.com/antipatterns/the-blob http://sourcemaking.com/antipatterns/the-blob]</ref>		<ref name = sourcemaking_tb> [http://sourcemaking.com/antipatterns/the-blob http://sourcemaking.com/antipatterns/the-blob]</ref>

Rbjeffer at 00:17, 30 November 2011

2011-11-30T00:17:30Z

← Older revision		Revision as of 00:17, 30 November 2011
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	The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />		The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />
	==~~Conclusions~~==		==Conclusion==

	In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.		In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.

Rbjeffer at 00:17, 30 November 2011

2011-11-30T00:17:07Z

← Older revision		Revision as of 00:17, 30 November 2011
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	The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />		The '''Golden Hammer''' design anti-pattern results from reusing a familiar solution that is a poor match for a new problem.<ref name="sourcemaking_gh" /> This can occur if the developers are simply comfortable with or used to an existing approach, or even the result of narrow-mindedness or hubris. It can also be the direct result of reliance on proprietary technologies or products, or a deliberate effort to try to build a previous projects' success into a new program. A '''Golden Hammer''' will typically manifest itself with poor performance or scalability.<ref name="sourcemaking_gh" />
	==Conclusions==		==Conclusions==

			In this article, we have described some of the most commonly occurring AntiPatterns. AntiPatterns comprise a set of defective processes and pitfalls in software development. They describe common errors in judgment or design made by both software engineers and project managers. They explain the causes of these errors, and offer suggestions for correcting the errors. AntiPatterns also define a standard set of vocabulary, so that they can be understood broadly. They are important for both programmers and managers to know and understand, in order to avoid costly mistakes.


	==Resources==		==Resources==