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

java.lang.Object
  org.eclipse.ocl.examples.domain.values.util.ValuesUtil
      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, OnlyIteration, 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.

Nested Class Summary

static class

AbstractIteration.MutableObject A MutableObject may be used as an iteration accumulatior containing a single changing value.

Field Summary

protected static java.lang.Object

CARRY_ON An out-of-band value that can be returned by updateAccumulator to signal that the iteration should carry on rather than terminate using the returned value.

Fields inherited from class org.eclipse.ocl.examples.domain.values.util.ValuesUtil

EMPTY_BAG, EMPTY_SET, FALSE_VALUE, INTEGER_MAX_VALUE, INTEGER_MIN_VALUE, INVALID_VALUE, LONG_MAX_VALUE, LONG_MIN_VALUE, NULL_STRING, NULL_VALUE, ONE_VALUE, TRUE_VALUE, UNLIMITED_VALUE, ZERO_VALUE

Constructor Summary

AbstractIteration()

Method Summary

java.lang.Object	evaluateIteration(DomainIterationManager iterationManager) The default iteration algorithm steps through the iteration domain by invoking DomainIterationManager.hasCurrent() and DomainIterationManager.advanceIterators().
protected java.lang.Object	resolveTerminalValue(DomainIterationManager iterationManager) Return the final result at the end of an iteration over all the source elements.
protected abstract java.lang.Object	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.values.util.ValuesUtil

asBagValue, asBoolean, asCollectionType, asCollectionValue, asInteger, asIntegerValue, asMetaclass, asNavigableObject, asObject, asOrderedCollectionValue, asOrderedSetValue, asRealValue, asSequenceValue, asSetValue, asString, asTupleValue, asType, asUniqueCollectionValue, asUnlimitedNaturalValue, asValue, bigDecimalValueOf, bigIntegerValueOf, characterValueOf, createBagAccumulatorValue, createBagOfEach, createBagRange, createBagValue, createCollectionAccumulatorValue, createInvalidValue, createObjectValue, createOrderedSetAccumulatorValue, createOrderedSetOfEach, createOrderedSetRange, createOrderedSetValue, createRange, createSequenceAccumulatorValue, createSequenceOfEach, createSequenceRange, createSequenceRange, createSequenceValue, createSetAccumulatorValue, createSetOfEach, createSetRange, createSetValue, createTupleOfEach, createTupleValue, createTupleValue, createTypeValue, getEcoreNumber, getTypeName, initAllStatics, integerValueOf, integerValueOf, integerValueOf, integerValueOf, integerValueOf, isBoxed, isCollectionValue, isIntegerNumber, isIntegerValue, isRealNumber, isUnboxed, isUnlimited, oclToString, realValueOf, realValueOf, realValueOf, realValueOf, realValueOf, stringValueOf, throwBooleanInvalidValueException, throwInvalidValueException, toString

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

Field Detail

CARRY_ON

@NonNull
protected static final java.lang.Object CARRY_ON

An out-of-band value that can be returned by updateAccumulator to signal that the iteration should carry on rather than terminate using the returned value.

Constructor Detail

AbstractIteration

public AbstractIteration()

Method Detail

evaluateIteration

@Nullable
public java.lang.Object evaluateIteration(@NonNull
                                                   DomainIterationManager iterationManager)

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:

java.lang.Exception

resolveTerminalValue

@Nullable
protected java.lang.Object resolveTerminalValue(@NonNull
                                                         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

@Nullable
protected abstract java.lang.Object updateAccumulator(@NonNull
                                                               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-CARRY_ON premature result of iteration, or CARRY_ON if complete

Throws:

java.lang.Exception