org.faktorips.runtime
Interface IDeltaComputationOptions

All Known Implementing Classes:

DeltaComputationOptionsByPosition

public interface IDeltaComputationOptions

Callback interface for the delta computation.

Author:

Jan Ortmann

Nested Class Summary

static class

IDeltaComputationOptions.ComputationMethod

Method Summary

boolean	areValuesEqual(Class<?> clazz, String property, Object value1, Object value2) Compares two values for equality by the given model class and property, where either one or both values may be null.
IDeltaComputationOptions.ComputationMethod	getMethod(String association) Returns if the delta computation computes child deltas per position/index or per object.
boolean	ignore(Class<?> clazz, String property) Returns true if the given property should be ignored in the delta computation.
boolean	isCreateSubtreeDelta() Controls whether delta objects for added or removed subtree elements should be created explicitly.
boolean	isSame(IModelObject object1, IModelObject object2) Returns true if the two objects represent the same conceptual object, otherwise false.

Method Detail

getMethod

IDeltaComputationOptions.ComputationMethod getMethod(String association)

Returns if the delta computation computes child deltas per position/index or per object.

1. Example for a 1-many association:
A contract version A has three coverages c0, c1, and c2. A second version B of the same contract has a new coverage cNew inserted between coverage c0 and c1. The coverages c0, c1,and c2 are unchanged except for their position.

If this method returns IDeltaComputationOptions.ComputationMethod.BY_POSITION, the following deltas are computed. position 0: version A:c0, version B:c0 => empty delta position 1: version A:c1, version B:cNew => changed position 2: version A:c2, version B:c1 => changed position 3: version A:none, version B:c2 => added

If this method returns IDeltaComputationOptions.ComputationMethod.BY_OBJECT, the following deltas are computed. c0: version A:position 0, version B:position 0 => empty delta c1: version A:position 1, version B:position 2 => moved c2: version A:position 2, version B:position 3 => moved cNew: version A:position none, version B:position 1 => added

2. Example for a 1-many association:
Same scenario as above, but now c1 is removed and no coverage is added.

If this method returns IDeltaComputationOptions.ComputationMethod.BY_POSITION, the following deltas are computed. position 0: version A:c0, version B:c0 => empty delta position 1: version A:c1, version B:v2 => changed position 2: version A:c2, version B:none => removed

If this method returns IDeltaComputationOptions.ComputationMethod.BY_OBJECT, the following deltas are computed. c0: version A:position 0, version B:position 0 => empty delta c1: version A:position 1, version B:position none => removed c2: version A:position 2, version B:position 1 => moved

Example for a 1-1 association:
A contract version A has the insured person p0. A second contract version B has the insured person p1.

If this method returns IDeltaComputationOptions.ComputationMethod.BY_POSITION, the following delta is computed. position 0: changed

If this method returns IDeltaComputationOptions.ComputationMethod.BY_OBJECT, the following deltas are computed. p1: removed p2: added

isSame

boolean isSame(IModelObject object1,
               IModelObject object2)

Returns true if the two objects represent the same conceptual object, otherwise false. What the conceptual object is, depends on the use case in that you need the delta computation and on your object model.

If the objects are for example contract versions, they represent the same contract, just at different point in times. In this case the check has to compare the contract numbers but ignore the version numbers. If the objects are coverages you might consider them the same, if they are of the same coverage type, e.g. both are accidental damages coverages.

ignore

boolean ignore(Class<?> clazz,
               String property)

Returns true if the given property should be ignored in the delta computation. If you compare for example two versions of the same contract, you might want to ignore the different in the creation time, as otherwise two versions would always be different.

Parameters:

clazz - The class the property belongs to.

property - The name of the property.

isCreateSubtreeDelta

boolean isCreateSubtreeDelta()

Controls whether delta objects for added or removed subtree elements should be created explicitly.

This method returns true if a delta should be created for added or removed subtrees. If this method returns false a delta is only created for the root of an added or removed subtree.

The creation of delta elements for subtree nodes is based on reflection and may cause a performance issue if used in massive delta computation with many added or removed subtrees.

Returns:

true if a delta should be created for every element of an added or removed subtree.

Since:

3.15

areValuesEqual

boolean areValuesEqual(Class<?> clazz,
                       String property,
                       Object value1,
                       Object value2)

Compares two values for equality by the given model class and property, where either one or both values may be null.

Parameters:

clazz - The class the property belongs to.

property - The name of the property.

value1 - The first value to compare

value2 - The second value to compare

Returns:

true if the values are the same