com.sdm.quasar.client.core.data.structure
Class AbstractSimpleComputation

java.lang.Object
  com.sdm.quasar.client.core.data.structure.AbstractSimpleComputation

All Implemented Interfaces:

Computation

Direct Known Subclasses:

IntegerToStringConversion

public abstract class AbstractSimpleComputation

extends java.lang.Object

implements Computation

A base class for simple cases of computations. This implementation assumes that the computation simply needs the values of all source nodes to compute its own value.

Implementations using this class must implement #computeFromValues(Object[]), {@link Computation#getType()}, and {@link Computation#getSourceTypes()}. If the computation is reversable, {@link #supportsReverse()} and {@link #reverseComputationToValues(Object, Object[])} must be overridden.

Computations that need to manipulate the context or that don't need the values of all source nodes should not be derived from this class but instead implement {@link com.sdm.quasar.client.core.data.structure.Computation} directly.

Version:

1.0

Author:

Thomas Wolf, sd&m AG, Bernd Olleck, sd&m AG

Constructor Summary

AbstractSimpleComputation()

Method Summary

abstract java.lang.Object	computeFromValues(java.lang.Object[] sourceValues) Performs the computation.
java.util.Set	computeIndexSet(ComputationValueAccess sourceValuesAccess, Context context) Performs the computation of a Set of the index values.
java.lang.Object	computeValue(ComputationValueAccess sourceValuesAccess, Context context) Performs the computation with an context. This implementation retrieves all source values using #getValues(ComputationValueAccess) and passes them on to computeFromValues(Object[]).
java.lang.Object[]	reverseComputationToValues(java.lang.Object targetValue, java.lang.Object[] sourceValues) Perform a reverse computation computes the correct source values with respect to the target value.
void	reverseValueComputation(java.lang.Object targetValue, ComputationValueAccess sourceValuesAccess, Context context) Perform a reverse computation computes the correct source values with respect to the target value with a context. The resulting new source values must be set using the ComputationValueAccess. This implementation retrieves all source values using #getValues(ComputationValueAccess) and passes them to reverseComputationToValues(Object, Object[]).
boolean	supportsReverse() This implementation returns false.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.sdm.quasar.client.core.data.structure.Computation

getSourceTypes, getType

Constructor Detail

AbstractSimpleComputation

public AbstractSimpleComputation()

Method Detail

computeValue

public final java.lang.Object computeValue(ComputationValueAccess sourceValuesAccess,
                                           Context context)

Performs the computation with an context. This implementation retrieves all source values using #getValues(ComputationValueAccess) and passes them on to computeFromValues(Object[]).

Specified by:

computeValue in interface Computation

Parameters:

sourceValuesAccess - the access source values

context - the context to be used

Returns:

the result

See Also:

Computation.computeValue(com.sdm.quasar.client.core.data.structure.ComputationValueAccess, com.sdm.quasar.client.core.data.Context)

reverseValueComputation

public final void reverseValueComputation(java.lang.Object targetValue,
                                          ComputationValueAccess sourceValuesAccess,
                                          Context context)

Perform a reverse computation computes the correct source values with respect to the target value with a context. The resulting new source values must be set using the ComputationValueAccess. This implementation retrieves all source values using #getValues(ComputationValueAccess) and passes them to reverseComputationToValues(Object, Object[]). The result of reverseComputationToValues(Object, Object[]) is set to the ComputationValueAccess.

Specified by:

reverseValueComputation in interface Computation

Parameters:

targetValue - the target value

sourceValuesAccess - the access current source values

context - the context to be used

See Also:

Computation.reverseValueComputation(java.lang.Object, com.sdm.quasar.client.core.data.structure.ComputationValueAccess, com.sdm.quasar.client.core.data.Context)

computeIndexSet

public java.util.Set computeIndexSet(ComputationValueAccess sourceValuesAccess,
                                     Context context)

Description copied from interface: Computation

Performs the computation of a Set of the index values. The method returns null for not indexed nodes.

Specified by:

computeIndexSet in interface Computation

Parameters:

sourceValuesAccess - the access source values

context - the context to be used

Returns:

a Set of the index values or null

See Also:

Computation.computeIndexSet(com.sdm.quasar.client.core.data.structure.ComputationValueAccess, com.sdm.quasar.client.core.data.Context)

computeFromValues

public abstract java.lang.Object computeFromValues(java.lang.Object[] sourceValues)

Performs the computation.

Parameters:

sourceValues - the source values

Returns:

the result

supportsReverse

public boolean supportsReverse()

This implementation returns false. Override this method if your computation is reversible.

Specified by:

supportsReverse in interface Computation

Returns:

true iff the computation supports a reverse computation

See Also:

Computation.supportsReverse()

reverseComputationToValues

public java.lang.Object[] reverseComputationToValues(java.lang.Object targetValue,
                                                     java.lang.Object[] sourceValues)

Perform a reverse computation computes the correct source values with respect to the target value. When passed to the method, the source values will have the current values if available.

This implementation throws an UnsupportedOperationException. Override this method if your computation is reversible.

Parameters:

targetValue - the target value

sourceValues - the current source values

Returns:

the new source values

Throws:

java.lang.UnsupportedOperationException - if the reverse computation is not supported