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diff --git a/src/site-docs/adoc/fragments/apex-policy-model/concepts-keys.adoc b/src/site-docs/adoc/fragments/apex-policy-model/concepts-keys.adoc new file mode 100644 index 000000000..d15152b01 --- /dev/null +++ b/src/site-docs/adoc/fragments/apex-policy-model/concepts-keys.adoc @@ -0,0 +1,54 @@ +// +// ============LICENSE_START======================================================= +// Copyright (C) 2016-2018 Ericsson. All rights reserved. +// ================================================================================ +// This file is licensed under the CREATIVE COMMONS ATTRIBUTION 4.0 INTERNATIONAL LICENSE +// Full license text at https://creativecommons.org/licenses/by/4.0/legalcode +// +// SPDX-License-Identifier: CC-BY-4.0 +// ============LICENSE_END========================================================= +// +// @author Sven van der Meer (sven.van.der.meer@ericsson.com) +// + +== Concepts and Keys + +Each element of the policy model is called a __concept__. +Each __concept__ is a subclass of the abstract __Concept__ class, as shown in the next figure. +Every concept implements the following abstract methods: + +.Concepts and Keys +image::apex-policy-model/ConceptsKeys.png[Concepts and Keys] + +* `getKey()` - gets the unique key for this concept instance in the system +* `validate()` - validates the structure of this concept, its sub-concepts and its relationships +* `clean()` - carries out housekeeping on the concept such as trimming strings, remove any hanging references +* `clone()` - creates a deep copy of an instance of this concept +* `equals()` - checks if two instances of this concept are equal +* `toString()` - returns a string representation of the concept +* `hashCode()` - returns a hash code for the concept +* `copyTo()` - carries out a deep copy of one instance of the concept to another instance, overwriting the target fields. + +All concepts must have a __key__, which uniquely identifies a concept instance. +The __key__ of a subclass of an __Concept__ must either be an `ArtifactKey` or an `ReferenceKey`. +Concepts that have a stand-alone independent existence such as __Policy__, __Task__, and __Event__ must have an `ArtifctKey` key. +Concepts that are contained in other concepts, that do not exist as stand-alone concepts must have an `ReferenceKey` key. +Examples of such concepts are __State__ and __EventParameter__. + +An `ArticactKey` has two fields; the __Name__ of the concept it is the key for and the concept's __Version__. +A concept's name must be unique in a given PolicyModel. +A concept version is represented using the well known __major.minor.path__ scheme as used in semantic versioning. + +A `ReferenceKey` has three fields. +The __UserKeyName__ and __UserKeyVersion__ fields identify the `ArtifactKey` of the concept in which the concept keyed by the `ReferenceKey` is contained. +The __LocalName__ field identifies the contained concept instance. +The __LocalName__ must be unique in the concepts of a given type contained by a parent. + +For example, a policy called `_SalesPolicy_` with a Version of `_1.12.4_` has a state called `_Decide_`. +The `_Decide_` state is linked to the `_SalesPolicy_` with a `ReferenceKey` with fields __UserKeyName__ of `_SalesPolicy_`, __UserKeyVersion__ of `_1.12.4_`, and __LocalName__ of `_Decide_`. +There must not be another state called `_Decide_` in the policy `_SalesPolicy_`. +However, there may well be a state called `_Decide_` in some other policy called `_PurchasingPolicy_`. + +Each concept in the model is also a JPA (link:https://en.wikipedia.org/wiki/Java_Persistence_API[Java Persistence API]) Entity. +This means that every concept can be individually persisted or the entire model can be persisted en-bloc to any persistence mechanism using an JPA framework such as link:http://hibernate.org/[Hibernate] or link:http://www.eclipse.org/eclipselink/[EclipseLink]. + |