org.eclipse.ocl.examples.impactanalyzer.configuration
Class ActivationOption

java.lang.Object
  org.eclipse.ocl.examples.impactanalyzer.configuration.ActivationOption

public class ActivationOption
extends java.lang.Object

Configures the ImpactAnalyzer and the InstanceScopeAnalysis components and choose between different implementation styles. A singleton instance of this class is managed by OptimizationActivation. The following options can be configured, either by invoking a setter or by passing the respective argument to the constructor:

• deltaPropagationActive (see isDeltaPropagationActive() and setDeltaPropagationActive(boolean): Tells if the instance scope analysis shall use a delta propagation and partial evaluation mechanism to decide early on if the subexpression(s) immediately affected by the change may propagate the change all the way to the overall expression's evaluation result. This will trigger OCL evaluations for subexpressions, some of which may fail for unknown variables, some of which may prove that the subexpression where the change "hit" doesn't propagate the change, leaving the overall expression unchanged. By and large, this saves significant efforts during re-evaluation as it reduces the set of context instances returned by ImpactAnalyzer.getContextObjects(org.eclipse.emf.common.notify.Notification) for many cases. Our measurements show that the additional efforts spent for the analysis gets amortized in all cases we have measured. Recommendation: set to true.
• tracebackStepISAActive: (see isTracebackStepISAActive() and setTracebackStepISAActive(boolean): Currently, there are two fundamentally different implementation strategies for the instance scope analysis (see also InstanceScopeAnalysis). One pre-computes one step object per (sub-)expression contained in the OCL expression's AST and executes them when ImpactAnalyzer.getContextObjects(org.eclipse.emf.common.notify.Notification) is invoked. This strategy lends itself well for an additional early pruning of options related to the unusedDetectionActive option explained below. If deselected by setting this option to false, a strategy is selected which materialized only those steps that actually perform some navigation or filtering on the model graph. The construction of this tree, according to our measurements, is slightly more expensive than the construction of the more elaborate step graph. On average, the two perform fairly similar. The key difference, as already mentioned, is that only when setting this option to true, the unusedDetectionActive option has any effect.
• unusedDetectionActive (see isUnusedDetectionActive() and setUnusedDetectionActive(boolean): Activates a performance improvement measure which aims to prove that the sub-expression where the change occurred is not used under the variable/parameter/self settings inferred from the information delivered about the change in the change Notification. For example, if a change occurs in an else branch of an if-expression and the condition can be proven to evaluate to true based on the information taken from the Notification, this proves that the subexpression that changed its value is not used in evaluating the overall expression. Therefore, the change does not impact the overall expression at all. This technique involves some up-front cost for determining the various checks to be performed. During ImpactAnalyzer.getContextObjects(org.eclipse.emf.common.notify.Notification) some additional cost is incurred for evaluating sub-expressions (such as an if-expression's condition, as exemplified above). For smaller models, performance seem to be on-par for both settings of this switch. We hope to prove that for certain cases where we see really bad performance without this option being used, using it would significantly shrink the number of elements considered to potentially have changed. This option can only be selected, if isTracebackStepISAActive() is true.
• operationCallSelectionActive (see isOperationCallSelectionActive() and setOperationCallSelectionActive(boolean): Activates a performance improvement measure which aims to minimize the OperationCallExp considered when tracing back through a self or parameter variable inside an operation body. Without this measure, all results obtained from tracing back through all possible calls to the operation considered will be used. With the measure activated, while all results will be computed and cached, only those specific to the call considered will be used further on. This makes the results crisper and smaller but may consume a little more performance during evaluation time because results need to be keyed by OperationCallExp expressions, causing more data structures to be maintained. This option can only be selected, if isTracebackStepISAActive() is true.

Constructor Summary

ActivationOption(boolean isDeltaPropagationActive, boolean isUnusedDetectionActive, boolean isTracebackStepISAActive, boolean isOperationCallSelectionActive, java.lang.String description)

Method Summary

java.lang.String	getActivationString()
java.lang.String	getOptionDescription()
boolean	isDeltaPropagationActive()
boolean	isOperationCallSelectionActive()
boolean	isTracebackStepISAActive()
boolean	isUnusedDetectionActive()
void	setDeltaPropagationActive(boolean isDeltaPropagationActive)
void	setOperationCallSelectionActive(boolean isOperationCallSelectionActive)
void	setTracebackStepISAActive(boolean isTracebackStepISAActive)
void	setUnusedDetectionActive(boolean isUnusedDetectionActive)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ActivationOption

public ActivationOption(boolean isDeltaPropagationActive,
                        boolean isUnusedDetectionActive,
                        boolean isTracebackStepISAActive,
                        boolean isOperationCallSelectionActive,
                        java.lang.String description)

Method Detail

setDeltaPropagationActive

public void setDeltaPropagationActive(boolean isDeltaPropagationActive)

isDeltaPropagationActive

public boolean isDeltaPropagationActive()

setTracebackStepISAActive

public void setTracebackStepISAActive(boolean isTracebackStepISAActive)

isTracebackStepISAActive

public boolean isTracebackStepISAActive()

isUnusedDetectionActive

public boolean isUnusedDetectionActive()

setUnusedDetectionActive

public void setUnusedDetectionActive(boolean isUnusedDetectionActive)

isOperationCallSelectionActive

public boolean isOperationCallSelectionActive()

setOperationCallSelectionActive

public void setOperationCallSelectionActive(boolean isOperationCallSelectionActive)

getActivationString

public java.lang.String getActivationString()

getOptionDescription

public java.lang.String getOptionDescription()