Difference between revisions of "Element Hierarchy Extension Point & Library"

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imported>Laurent
 
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  B - API to test these relations and traverse them
 
  B - API to test these relations and traverse them
 
  C - Enforcement of the authorized relations when modifying the DB
 
  C - Enforcement of the authorized relations when modifying the DB
  D - Behaviour while loading a file (including a file with invalid parent-child relations occurrences)
+
  D- What about the compatibilty with the file upgrade mechanism?
E- What about the compatibilty with the file upgrade mechanism?
 
 
----
 
----
  
 
= Some identified difficulties =
 
= Some identified difficulties =
 
== Initialization of elements from non UI components ==
 
 
The following ElementDescRegistry method, shows the dependency between an element creation and the initialization of its attributes with default values.
 
 
        public <T extends IInternalElement> T createElement(
 
final IInternalElement root, IInternalElement parent,
 
final IInternalElementType<T> type, final IInternalElement sibling)
 
throws RodinDBException {
 
final T newElement = parent.createChild(type, sibling, null);
 
final IAttributeDesc[] attrDesc = getAttributes(type);
 
for (IAttributeDesc desc : attrDesc) {
 
desc.getManipulation().setDefaultValue(newElement, null);    // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
 
}
 
return newElement;
 
}
 
 
The protocol shall be changed to take into account this initialization outside from the graphical manipulation.
 
Doing the initialization at org.eventb.core level is possible by registering a special "attribute initializer". <br>
 
WARNING : The required attribute is only available for "choice" attributes. Can't it be available for all kind of attributes?
 
  
 
== Correspondence between UI manipulation and "core" elements ==
 
== Correspondence between UI manipulation and "core" elements ==
What if an element is not defined in the UI but defined in the hierarchy of a given core element?<br>
+
If some element or attribute relationship is declared at the database level, but there is no corresponding {{ident|editorItem}} for it, it will be ignored by the UI. This is similar to the previous situation where some elements or attributes could be present in the database but not in the user interface hierarchy.
>>> ANSWER : it seems that any contributor to the UI manages the extensions of the datat model. The responsability is thus left to him.<br>
 
>>> A element for which there is no UI correspondance will not be displayed.
 
  
== Operation on elements shall be enforced ==
 
 
        private <T extends IInternalElement> OperationCreateElement getCreateElement(
 
IInternalElement parent, IInternalElementType<T> type,
 
IInternalElement sibling, IAttributeValue[] values) {
 
OperationCreateElement op = new OperationCreateElement(
 
createDefaultElement(parent, type, sibling));
 
op.addSubCommande(new ChangeAttribute(values));
 
return op;
 
}
 
  
''The Operation model similar to a kind of transaction mechanism, should be made available from the DB layer.''<br>
 
''The relations when using such layer shall be enforced and any invalid operation could be rejected.''
 
  
 
= Proposal =
 
= Proposal =
 
== Hierarchy between elements ==
 
  
 
The part concerning element definition and hierarchy will go to a dedicated extension point in the database.
 
The part concerning element definition and hierarchy will go to a dedicated extension point in the database.
Line 66: Line 29:
 
=== A - hierarchy definition ===
 
=== A - hierarchy definition ===
  
Here is the definition of such an extension point : org.rodinp.core.dataModel ???  or org.rodinp.core.internalElementHierarchy ???
+
Here is the definition of the new extension point : org.rodinp.core.itemRelations which describes the possible children and attributes of internal elements.
  
 
  Configuration Markup:
 
  Configuration Markup:
  <!ELEMENT extension ((childRelation | attributeRelation | autoNaming)+)>
+
  <!ELEMENT extension (relationship+)>
 
  <!ATTLIST extension
 
  <!ATTLIST extension
 
  point CDATA #REQUIRED
 
  point CDATA #REQUIRED
Line 76: Line 39:
 
  >
 
  >
 
   
 
   
  <!ELEMENT elementRelationship (childType)+>
+
  <!ELEMENT relationship ((childType | attributeType)+)>
 
  <!ATTLIST elementRelationship
 
  <!ATTLIST elementRelationship
 
  parentTypeId CDATA #REQUIRED
 
  parentTypeId CDATA #REQUIRED
Line 85: Line 48:
 
  <!ATTLIST childType
 
  <!ATTLIST childType
 
  typeId                CDATA #REQUIRED
 
  typeId                CDATA #REQUIRED
implicitChildProvider CDATA #IMPLIED
 
 
  >
 
  >
 
  typeId - Element type of the child, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).
 
  typeId - Element type of the child, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).
 
<!ELEMENT attributeRelationship (attributeType)+>
 
<!ATTLIST attributeRelationship
 
elementTypeId CDATA #REQUIRED
 
>
 
elementTypeId - Element type of the element, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).
 
 
   
 
   
 
  <!ELEMENT attributeType EMPTY>
 
  <!ELEMENT attributeType EMPTY>
 
  <!ATTLIST attributeType
 
  <!ATTLIST attributeType
 
  typeId CDATA #REQUIRED
 
  typeId CDATA #REQUIRED
class  CDATA #REQUIRED
 
 
  >
 
  >
Describes how to graphically display a Rodin attribute of type boolean.
 
 
 
  attributeTypeId - Id of the Rodin attribute type to which this description applies (see extension point org.rodinp.core.attributeTypes).
 
  attributeTypeId - Id of the Rodin attribute type to which this description applies (see extension point org.rodinp.core.attributeTypes).
 
<!ELEMENT autoNaming EMPTY>
 
<!ATTLIST autoNaming
 
elementTypeId          CDATA #REQUIRED
 
attributeDescriptionId CDATA #REQUIRED
 
namePrefix             CDATA #REQUIRED
 
>
 
Describes how to automatically name an element. The autoNaming definition is unique for a given element type.
 
 
elementTypeId - Element type of the element, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).
 
namePrefix - default prefix to name the element
 
 
   
 
   
 
The use of such extension point is obvious in org.eventb.core plug-in, as it would complement the extensions of org.rodinp.core.attributeTypes and org.rodinp.core.internalElementTypes.
 
The use of such extension point is obvious in org.eventb.core plug-in, as it would complement the extensions of org.rodinp.core.attributeTypes and org.rodinp.core.internalElementTypes.
  
== Data model operation ==
+
=== B - API to declare and test the element/attribute relations and traverse them ===
The ElementManipulationFacade, support for modifications over the Database, should be provided by the Event-B Core plug-in.<br>
 
The IAttributeManipulation interface should be also provided by the Event-B Core plug-in as it concerns the manipulation done on the attribute in the DB.
 
  
The information about the rendering of an element or an attribute, should not be deduced from the attribute itself (e.g. choiceAttribute vs. toggleAttribute vs. textAttribute), it should be given in the UI.
+
The API of the Rodin database is extended as follows:
 +
 
 +
* interface IInternalElementType is extended with methods
 +
 
 +
  IInternalElementType<?>[] getParentTypes();
 +
  IInternalElementType<?>[] getChildTypes();
 +
  IAttributeType[] getAttributeTypes();
 +
 
 +
  boolean canParent(IInternalElementType<?> childType);
 +
  boolean canCarry(IAttributeType attrType);
 +
 
 +
* interface IAttributeType is extended with methods
 +
 
 +
  IInternalElementType<?>[] getElementTypes();
 +
 
 +
  boolean isAttributeOf(IInternalElementType<?> elementType);
 +
 
 +
This list might be later extended with new methods such as
 +
{{ident|isAncestorOf}} if this proves useful.
 +
 
 +
=== D - Compatibility with the upgrade mechanism ===
 +
 
 +
Things start with the org.rodinp.core.conversion extension point.<br>
 +
The modifications are done in XPATH  there is no incompatibility introduced here.  
  
 
== UI related information ==
 
== UI related information ==
 
The part concerning how to display elements and UI related info will stay in the editorItems extension point and shall point to an element definition and hierachy.<br>
 
The part concerning how to display elements and UI related info will stay in the editorItems extension point and shall point to an element definition and hierachy.<br>
 
Relationships will disappear from the editorItems extension point.
 
Relationships will disappear from the editorItems extension point.
 +
  
 
[[Category:Design_proposal]]
 
[[Category:Design_proposal]]

Latest revision as of 13:17, 12 October 2012

The UI in Rodin 2.x contains an extension point org.eventb.ui.editorItems that groups the both following information:

  • the definition of elements and attributes and their hierarchy, and the way they are created
  • the information needed to correctly display and edit these elements in the various editors and UI components

It appears obvious that the first information should be defined from an extension that belongs to the Database. To fullfil the above statement, the current extension point org.eventb.ui.editorItems should be split in two. The existing extension point was also heterogenous. Indeed, whereas the element relationships were concerning element types, the attribute relationship were concerning element types and references to UI defined attributes (referring to core attributes).
There is no need for such an indirection.


The proposal should concern :

A - Relationship declaration (new extension point)
B - API to test these relations and traverse them
C - Enforcement of the authorized relations when modifying the DB
D- What about the compatibilty with the file upgrade mechanism?

Some identified difficulties

Correspondence between UI manipulation and "core" elements

If some element or attribute relationship is declared at the database level, but there is no corresponding

editorItem

for it, it will be ignored by the UI. This is similar to the previous situation where some elements or attributes could be present in the database but not in the user interface hierarchy.


Proposal

The part concerning element definition and hierarchy will go to a dedicated extension point in the database.

A - hierarchy definition

Here is the definition of the new extension point : org.rodinp.core.itemRelations which describes the possible children and attributes of internal elements.

Configuration Markup:
<!ELEMENT extension (relationship+)>
<!ATTLIST extension
point CDATA #REQUIRED
id    CDATA #IMPLIED
name  CDATA #IMPLIED
>

<!ELEMENT relationship ((childType | attributeType)+)>
<!ATTLIST elementRelationship
parentTypeId CDATA #REQUIRED
>
parentTypeId - Element type of the parent, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).

<!ELEMENT childType EMPTY>
<!ATTLIST childType
typeId                CDATA #REQUIRED
>
typeId - Element type of the child, must be the unique ID of a Rodin internal element type (see extension point org.rodinp.core.internalElementTypes).

<!ELEMENT attributeType EMPTY>
<!ATTLIST attributeType
typeId CDATA #REQUIRED
>
attributeTypeId - Id of the Rodin attribute type to which this description applies (see extension point org.rodinp.core.attributeTypes).

The use of such extension point is obvious in org.eventb.core plug-in, as it would complement the extensions of org.rodinp.core.attributeTypes and org.rodinp.core.internalElementTypes.

B - API to declare and test the element/attribute relations and traverse them

The API of the Rodin database is extended as follows:

  • interface IInternalElementType is extended with methods
 IInternalElementType<?>[] getParentTypes();
 IInternalElementType<?>[] getChildTypes();
 IAttributeType[] getAttributeTypes();
 boolean canParent(IInternalElementType<?> childType);
 boolean canCarry(IAttributeType attrType);
  • interface IAttributeType is extended with methods
 IInternalElementType<?>[] getElementTypes();
 boolean isAttributeOf(IInternalElementType<?> elementType);

This list might be later extended with new methods such as

isAncestorOf

if this proves useful.

D - Compatibility with the upgrade mechanism

Things start with the org.rodinp.core.conversion extension point.
The modifications are done in XPATH there is no incompatibility introduced here.

UI related information

The part concerning how to display elements and UI related info will stay in the editorItems extension point and shall point to an element definition and hierachy.
Relationships will disappear from the editorItems extension point.