org.eclipse.ocl.examples.domain.library
Class AbstractIteration

java.lang.Object
  org.eclipse.ocl.examples.domain.library.AbstractFeature
      org.eclipse.ocl.examples.domain.library.AbstractIteration

All Implemented Interfaces:

LibraryFeature, LibraryIteration

Direct Known Subclasses:

AnyIteration, ClosureIteration, CollectIteration, CollectNestedIteration, ExistsIteration, ForAllIteration, IsUniqueIteration, IterateIteration, OneIteration, RejectIteration, SelectIteration, SortedByIteration

public abstract class AbstractIteration
extends AbstractFeature
implements LibraryIteration

AbstractIteration realizes shared characteristics of library iterations by providing a default iteration algorithm with a call-back at each iteration step.

Constructor Summary

AbstractIteration()

Method Summary

Value	evaluateIteration(DomainIterationManager iterationManager) The default iteration algorithm steps through the iteration domain by invoking DomainIterationManager.hasCurrent() and DomainIterationManager.advanceIterators().
protected Value	resolveTerminalValue(DomainIterationManager iterationManager) Return the final result at the end of an iteration over all the source elements.
protected abstract Value	updateAccumulator(DomainIterationManager iterationManager) Update the accumulatorValue with the bodyValue resulting from the current iteration for which the iterators define the context in the environment.

Methods inherited from class org.eclipse.ocl.examples.domain.library.AbstractFeature

getLibraryValidator, getValidator

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.ocl.examples.domain.library.LibraryIteration

createAccumulatorValue

Methods inherited from interface org.eclipse.ocl.examples.domain.library.LibraryFeature

getValidator

Constructor Detail

AbstractIteration

public AbstractIteration()

Method Detail

evaluateIteration

public Value evaluateIteration(DomainIterationManager iterationManager)
                        throws InvalidValueException

The default iteration algorithm steps through the iteration domain by invoking DomainIterationManager.hasCurrent() and DomainIterationManager.advanceIterators(). At each step updateAccumulator(DomainIterationManager) is invoked to update the accumulator for that step. A non-null return causes a premature exit and forms the return from the overall evaluation. If all steps complete resolveTerminalValue(DomainIterationManager) is invoked to provide the return value.

Derived classes may override this method to change the iteration algorithm or override the call-backs to customize the default iteration.

Specified by:

evaluateIteration in interface LibraryIteration

Parameters:

iterationManager - the iteration space

Returns:

the result

Throws:

InvalidValueException - if a body evaluates to invalid

resolveTerminalValue

protected Value resolveTerminalValue(DomainIterationManager iterationManager)

Return the final result at the end of an iteration over all the source elements. The default implementation just returns the accumulator. Derived iterations should override.
This method is bypassed if the iteration ends prematurely.

Parameters:

iterationManager - the iteration context

Returns:

the result

updateAccumulator

protected abstract Value updateAccumulator(DomainIterationManager iterationManager)

Update the accumulatorValue with the bodyValue resulting from the current iteration for which the iterators define the context in the environment.

Parameters:

iterationManager - the iteration context

Returns:

non-null premature result of iteration, or null if complete

Throws:

InvalidEvaluationException