Transcript Hyper/J George Fairbanks Objects and Aspects 12 November 2004 Harumph! Too cold! Too hot! 6 November 2015 Everything stinks!

Hyper/J
George Fairbanks
Objects and Aspects
12 November 2004
Harumph!
Too cold!
Too hot!
6 November 2015
Everything
stinks!
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Outline
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History
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Hyper/J
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Discussion
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Subjects
Multi-Dimensional Separation of Concerns
Artifact structure
Hyperspaces
Concerns
Hypermodules
Merging
Experience
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History: Subjects
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Objects are good because
of polymorphism and
encapsulation
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In a large team, different
programmers want to
extend the object to add
their functionality
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How is a poor
programmer supposed to
anticipate all those
features?
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History: MDSoC
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MDSoC= Multi-Dimensional Separation of Concerns
Meta, very meta
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Hyperslice
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“Tyranny of the dominant decomposition”
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Tangling
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Scattering
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A set of modules where all code is for a given concern
“Declaratively complete” – not a simple partition
The primary structure of a system
One method has code for many concerns
Code for one concern in many methods
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Hyper/J
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An “instance of MDSoC” that
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Note: No Base/Aspect duality like in AspectJ
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Various composition rules can be defined
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enables the definition of Java concerns (hyperslices)
merges the concerns into a complete Java program
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Hyper/J Artifact Structure
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… and processing
Hyperspace
Hyperslice
Hyperslice
Hyperslice
Hyperslice
Hyperslice
Hyper/J
Hypermodule
Hyperslice
Hyperslice
Merge
Rule
Hyperslice
Hyperslice
javac
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Hyperspace
hyperspace
composable
composable
composable
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DemoHyperspace
class demo.ObjectDimension.*;
class demo.StyleChecker.*;
class demo.Observer.*;
The Hyperspace definition is equivalent to defining
the files in a project
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Hyperslice
package demo.ObjectDimension : Feature.Kernel
operation check : Feature.Check
operation display : Feature.Display
operation eval : Feature.Eval
operation check_process : Feature.Check
operation display_process : Feature.Display
operation eval_process : Feature.Eval
operation process : Feature.None
package demo.StyleChecker : Feature.StyleChecker
package demo.Observer : Feature.Logging
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Maps source code to concerns (features / aspects /
hyperslices)
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Hypermodule
hypermodule DemoSEE
hyperslices:
Feature.Kernel, Feature.Check, Feature.Display,
Feature.Eval, Feature.StyleChecker, Feature.Logging;
relationships:
mergeByName;
equate operation Feature.Kernel.process, Feature.Check.check_process,
Feature.Display.display_process, Feature.Eval.eval_process;
bracket "*"."{~_,~<}*"
before Feature.Logging.LoggedClass._beforeInvoke( $ClassName, $OperationName ),
after Feature.Logging.LoggedClass._afterInvoke( $ClassName, $OperationName );
set summary function
for action DemoSEE.BinaryOperator.check
to action DemoSEE.Expression.summarizeCheck;
end hypermodule;
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Defines the composition of the concerns
Detail on next slide
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Merging (Weaving)
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What matches?
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Equate
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Bracket
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Set summary function
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mergeByName, nonCorrespondingMerge,
overrideByName
different names but really the same
Methods should be preceded/followed by others
What is the return value of a composed function?
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Simple Example
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In foo.java
public class Foo {
public void sayHi() {
System.out.println(“Hi”);
}
}
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In bar.java
public class Bar {
public void sayBye() {
System.out.println(“Bye”);
}
}
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In demo.opt config file
-hyperspace
hyperspace demo
composable class Foo;
composable class Bar;
-concerns
class Foo : Feature.hi
class Bar : Feature.bye
-hypermodules
hypermodule DemoHM
hyperslices: Feature.hi, Feature.bye;
relationships:
mergeByName;
equate operation Feature.hi.sayHi,
Feature.bye.sayBye
into greet;
merge class Feature.hi.Foo, Feature.bye.Bar;
end hypermodule;
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Hyper/J Experience
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Results from Murphy et al.
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Results from Chavez et al.
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Compared AspectJ, Hyper/J, LSOC tools
Still need to decide structures in advance
Concerns should not be tangled in a method
Refactoring tools needed
Wrote an AspectJ program
Restructured it for Hyper/J
Hyper/J may be less readable
Hyper/J externalized composition rules helpful vs.
AspectJ’s internal dominates rule
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Tooling: CME
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CME= Concern Manipulation Environment
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I would have a live demo of CME here but all I can
seem to do is hang it. It is version 0.1.2.
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Discussion
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Comparison with AspectJ
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No “base/aspect dichotomy”, but “Kernel” hyperslice
appears commonly
Within-method concerns: which is better?
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When is program evolution easier, harder?
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What are the programmer’s benefits, burdens?
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If you owned a company, how would you decide
whether or not to use Hyper/J?
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