ExpressionTreeWalker

java.lang.Object
- de.uka.ipd.sdq.beagle.core.evaluableexpressions.util.ExpressionTreeWalker

Direct Known Subclasses:

PartialExpressionTreeWalker
```
public abstract class ExpressionTreeWalker
extends Object
```
Interface for visitors traversing an EvaluableExpression’s inner expressions. This class does not define the logic of the traversal but only a common interface with hooks to interact with it.
Implementors will define an algorithm resulting in some inner expressions of an EvaluableExpression (hereafter to be called the “root expression”) being visited and left in a certain order. The following hook types are offered:
- at: called when the traversal first reaches an expression.
- after: called when leaving an expression.
Every hook type is offered for every EvaluableExpression in de.uka.ipd.sdq.beagle.core.evaluableexpressions. Additionally, there is an other hook for each type. It is called for every expression type no hook was defined for. If a hook is to be defined for an expression type but the other hook is to be called for the expression anyway, the super hook can be called. Example:
```
 
 class MyWalker extends ExpressionTreeWalker {

        @Override
        void atAddition(AdditionExpression expression) {
                // some code
        }

        @Override
        void atMultiplication(MultiplicationExpression expression) {
                // some code
                super.atMultiplication(expression);
                // more code
        }

        @Override
        void atOther(EvaluableExpression expression) {
                // will be called for every expression but AdditionExpressions
        }
 }
 
 
```
MyWalker#atOther will be called when first visiting any EvaluableExpression, except when visiting an AdditionExpression.
Furthermore, the class offers two general purpose hooks, atExpression(de.uka.ipd.sdq.beagle.core.evaluableexpressions.EvaluableExpression) and afterExpression(de.uka.ipd.sdq.beagle.core.evaluableexpressions.EvaluableExpression), that are always called for any expression. These will be called before the expression’s specific hook (which implies that they will also be called before the other hook).

Constructor Summary

Constructors
Constructor and Description

ExpressionTreeWalker()

Constructors
Constructor and Description
`ExpressionTreeWalker()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`afterAddition(AdditionExpression expression)` Called when leaving an `AdditionExpression`.
`protected void`	`afterComparison(ComparisonExpression expression)` Called when leaving a `ComparisonExpression`.
`protected void`	`afterConstant(ConstantExpression expression)` Called when leaving a `ConstantExpression`.
`protected void`	`afterDivision(DivisionExpression expression)` Called when leaving a `DivisionExpression`.
`protected void`	`afterExponentation(ExponentationExpression expression)` Called when leaving an `ExponentationExpression`.
`protected void`	`afterExponentialFunction(ExponentialFunctionExpression expression)` Called when leaving an `ExponentialFunctionExpression`.
`protected void`	`afterExpression(EvaluableExpression expression)` Called when leaving any `EvaluableExpression`.
`protected void`	`afterIfThenElse(IfThenElseExpression expression)` Called when leaving an `IfThenElseExpression`.
`protected void`	`afterLogarithm(LogarithmExpression expression)` Called when leaving a `LogarithmExpression`.
`protected void`	`afterMultiplication(MultiplicationExpression expression)` Called when leaving a `MultiplicationExpression`.
`protected void`	`afterNaturalLogarithm(NaturalLogarithmExpression expression)` Called when leaving a `NaturalLogarithmExpression`.
`protected void`	`afterOther(EvaluableExpression expression)` Called when leaving any `EvaluableExpression` no hook was defined for.
`protected void`	`afterSine(SineExpression expression)` Called when leaving a `SineExpression`, after its inner expressions will be visited.
`protected void`	`afterSubtraction(SubtractionExpression expression)` Called when leaving a `SubtractionExpression`.
`protected void`	`afterVariable(EvaluableVariable expression)` Called when leaving an `EvaluableVariable`.
`protected void`	`atAddition(AdditionExpression expression)` Called when first visiting an `AdditionExpression`.
`protected void`	`atComparison(ComparisonExpression expression)` Called when first visiting a `ComparisonExpression`.
`protected void`	`atConstant(ConstantExpression expression)` Called when first visiting a `ConstantExpression`.
`protected void`	`atDivision(DivisionExpression expression)` Called when first visiting a `DivisionExpression`.
`protected void`	`atExponentation(ExponentationExpression expression)` Called when first visiting an `ExponentationExpression`.
`protected void`	`atExponentialFunction(ExponentialFunctionExpression expression)` Called when first visiting an `ExponentialFunctionExpression`.
`protected void`	`atExpression(EvaluableExpression expression)` Called when visiting any `EvaluableExpression`.
`protected void`	`atIfThenElse(IfThenElseExpression expression)` Called when first visiting an `IfThenElseExpression`.
`protected void`	`atLogarithm(LogarithmExpression expression)` Called when first visiting a `LogarithmExpression`.
`protected void`	`atMultiplication(MultiplicationExpression expression)` Called when first visiting a `MultiplicationExpression`.
`protected void`	`atNaturalLogarithm(NaturalLogarithmExpression expression)` Called when first visiting a `NaturalLogarithmExpression`.
`protected void`	`atOther(EvaluableExpression expression)` Called when first visiting any `EvaluableExpression` no hook was defined for.
`protected void`	`atSine(SineExpression expression)` Called when first visiting a `SineExpression`.
`protected void`	`atSubtraction(SubtractionExpression expression)` Called when first visiting a `SubtractionExpression`.
`protected void`	`atVariable(EvaluableVariable expression)` Called when first visiting an `EvaluableVariable`.
`protected abstract int`	`getTraversalDepth()` Queries how “deep” the currently visited expression is in the visited tree.
`protected abstract int`	`getVisitedCount()` Queries how many expressions have been visited during the momentary traversal.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ExpressionTreeWalker
```
public ExpressionTreeWalker()
```
- Method Detail
  - getVisitedCount
```
protected abstract int getVisitedCount()
```
    Queries how many expressions have been visited during the momentary traversal. This value is only reset when starting a new visit a new expression, it can thus be used to determine how many expressions were visited after a traversal.
    
    Returns:
    
    The amount of visited expressions during the current visit.
  - getTraversalDepth
```
protected abstract int getTraversalDepth()
```
    Queries how “deep” the currently visited expression is in the visited tree.
    
    Returns:
    
    how many at hooks have been called - how many after hooks have been called - 1. Will be 0 at the root expression and -1 at the before and after a traversal.
  - atOther
```
protected void atOther(EvaluableExpression expression)
```
    Called when first visiting any EvaluableExpression no hook was defined for. See the class description for details.
    
    Parameters:
    
    expression - The momentarily visited expression.
    
    See Also:
    
    atExpression(EvaluableExpression)
  - atExpression
```
protected void atExpression(EvaluableExpression expression)
```
    Called when visiting any EvaluableExpression. Contrary to atOther(EvaluableExpression), this hook will always be called, no matter if an overridden specific hook exists for expression.
    
    Parameters:
    
    expression - The momentarily visited expression.
    
    See Also:
    
    atOther(EvaluableExpression)
  - atAddition
```
protected void atAddition(AdditionExpression expression)
```
    Called when first visiting an AdditionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atMultiplication
```
protected void atMultiplication(MultiplicationExpression expression)
```
    Called when first visiting a MultiplicationExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atVariable
```
protected void atVariable(EvaluableVariable expression)
```
    Called when first visiting an EvaluableVariable.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atComparison
```
protected void atComparison(ComparisonExpression expression)
```
    Called when first visiting a ComparisonExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atConstant
```
protected void atConstant(ConstantExpression expression)
```
    Called when first visiting a ConstantExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atDivision
```
protected void atDivision(DivisionExpression expression)
```
    Called when first visiting a DivisionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atExponentation
```
protected void atExponentation(ExponentationExpression expression)
```
    Called when first visiting an ExponentationExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atExponentialFunction
```
protected void atExponentialFunction(ExponentialFunctionExpression expression)
```
    Called when first visiting an ExponentialFunctionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atIfThenElse
```
protected void atIfThenElse(IfThenElseExpression expression)
```
    Called when first visiting an IfThenElseExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atLogarithm
```
protected void atLogarithm(LogarithmExpression expression)
```
    Called when first visiting a LogarithmExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atNaturalLogarithm
```
protected void atNaturalLogarithm(NaturalLogarithmExpression expression)
```
    Called when first visiting a NaturalLogarithmExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atSine
```
protected void atSine(SineExpression expression)
```
    Called when first visiting a SineExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - atSubtraction
```
protected void atSubtraction(SubtractionExpression expression)
```
    Called when first visiting a SubtractionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterOther
```
protected void afterOther(EvaluableExpression expression)
```
    Called when leaving any EvaluableExpression no hook was defined for. See the class description for details.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterExpression
```
protected void afterExpression(EvaluableExpression expression)
```
    Called when leaving any EvaluableExpression. Contrary to afterOther(EvaluableExpression), this hook will always be called, no matter if an overridden specific hook exists for expression.
    
    Parameters:
    
    expression - The momentarily visited expression.
    
    See Also:
    
    afterOther(EvaluableExpression)
  - afterAddition
```
protected void afterAddition(AdditionExpression expression)
```
    Called when leaving an AdditionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterMultiplication
```
protected void afterMultiplication(MultiplicationExpression expression)
```
    Called when leaving a MultiplicationExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterVariable
```
protected void afterVariable(EvaluableVariable expression)
```
    Called when leaving an EvaluableVariable.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterComparison
```
protected void afterComparison(ComparisonExpression expression)
```
    Called when leaving a ComparisonExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterConstant
```
protected void afterConstant(ConstantExpression expression)
```
    Called when leaving a ConstantExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterDivision
```
protected void afterDivision(DivisionExpression expression)
```
    Called when leaving a DivisionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterExponentation
```
protected void afterExponentation(ExponentationExpression expression)
```
    Called when leaving an ExponentationExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterExponentialFunction
```
protected void afterExponentialFunction(ExponentialFunctionExpression expression)
```
    Called when leaving an ExponentialFunctionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterIfThenElse
```
protected void afterIfThenElse(IfThenElseExpression expression)
```
    Called when leaving an IfThenElseExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterLogarithm
```
protected void afterLogarithm(LogarithmExpression expression)
```
    Called when leaving a LogarithmExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterNaturalLogarithm
```
protected void afterNaturalLogarithm(NaturalLogarithmExpression expression)
```
    Called when leaving a NaturalLogarithmExpression.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterSine
```
protected void afterSine(SineExpression expression)
```
    Called when leaving a SineExpression, after its inner expressions will be visited.
    
    Parameters:
    
    expression - The momentary visited expression.
  - afterSubtraction
```
protected void afterSubtraction(SubtractionExpression expression)
```
    Called when leaving a SubtractionExpression.
    
    Parameters:
    
    expression - The momentary visited expression.

Class ExpressionTreeWalker

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ExpressionTreeWalker

Method Detail

getVisitedCount

getTraversalDepth

atOther

atExpression

atAddition

atMultiplication

atVariable

atComparison

atConstant

atDivision

atExponentation

atExponentialFunction

atIfThenElse

atLogarithm

atNaturalLogarithm

atSine

atSubtraction

afterOther

afterExpression

afterAddition

afterMultiplication

afterVariable

afterComparison

afterConstant

afterDivision

afterExponentation

afterExponentialFunction

afterIfThenElse

afterLogarithm

afterNaturalLogarithm

afterSine

afterSubtraction