View source

From Eclipsepedia

You do not have permission to do that, for the following reason:
The action you have requested is limited to users in the group user.
You can view and copy the source of this page:
Labels represent pieces of text possibly associated with icons on diagram surface. Text may be edited using inplace facility. There are many possibilities to construct labels but all of them are grouped in four usecases:

'''1. "feature based label"'''

Label is always defined in context of a diagram node or a link. If it's based on ''EClass'' from domain model then label may be used to represent attribute(s) of this class. Tooling will generate code that constructs label text and converts user input to the new value for attribute(s).

'''2. "design label"'''

It may be desirable to have a label that is not stored in domain model. Tooling may generate code that will use notation style (''DescriptionStyle'' for example) to store label text in notation model.

'''3. "default label"'''

This is a read-only label with fixed text.

'''4. "custom label"'''

GMF runtime defines ''IParser'' interface that is responsible to provide label text and editing support. In this usecase toolsmith is supposed to provide his own ''IParser'' implementation.

==Graphical Definition==

The only possible label figure is ''Label''. In generated diagram editor the actual figure may be ''Label'' from Draw2D or ''WrapLabel'' from GMF runtime. Attribute "text" of the figure is a text shown on diagram when parser is not available.

To access to this Label figure, a ''Child Access'' must be created in the figure where the label has been added. This ''Child Access'' will be used by the ''DiagramLabel'' to get the ''Label''.

Position of label figure within the model is important; it's used to determine whether label should be inner or external. Link labels are always external but node labels may be located whether inside node figure or "float" near it. If label figure is contained within parent node figure (directly or indirectly) it's inner label.

''DiagramLabel'' element refers to the label figure and is being referenced by ''LabelMapping'' from mapping models. If "elementIcon" attribute is set then label uses icon from EMF item providers. The following visual facets are recognized by tooling in ''DiagramLabel'':
*''AlignmentFacet'' - specifies link label position relative to the link figure; in generator model alignment is copied to "alignment" property of ''GenLinkLabel'' 
*''LabelOffsetFacet'' - initial distance between the label and node / link figure; in generator model represented by ''LabelOffsetAttributes'' instance in label viewmap

==Mapping==

''LabelMapping'' and its subclasses define label within the mapping model.

Basic ''LabelMapping'' instance supports 3<sup>rd</sup> and 4<sup>th</sup> usecases. It has "diagramLabel" reference to graphical definition and "readOnly" flag.

''FeatureLabelMapping'' extends ''LabelMapping'' to support 1<sup>st</sup> usecase by referencing domain attributes and providing format options:
*"features" reference: at least one attribute from domain model; all attributes should be defined within ''EClass'' of parent node / link
*"editableFeatures" reference: same as "features" reference but used within inplace editor; if it's empty then "features" reference is used
*"viewPattern": pattern to construct label text from feature value(s)
*"editorPattern": pattern to construct text for inplace editor from feature value(s)
*"editPattern": pattern to parse text entered by user in new feature value(s)
*"viewMethod": method to produce text from feature value(s) by pattern; used with "viewPattern" and "editorPattern"
*"editMethod": method to parse text entered by user in new feature value(s); used with "editPattern"

Currently supported methods are:
*MESSAGE_FORMAT uses [http://java.sun.com/j2se/1.5.0/docs/api/java/text/MessageFormat.html java.text.MessageFormat] class ''(e.g. "{1}: {2}")''
** The first feature starts at "{0}", the second will be "{1}", etc.
** If you set the ''View Pattern'', you will also have to set the ''Edit Pattern''; setting the edit pattern to "{0}" will replace the first feature with text entered in, etc.
*NATIVE only one attribute should be specified; calls EcoreUtil.convertToString(...) / EcoreUtil.createFromString(...) methods
*REGEXP calls [http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html#split(java.lang.String) String.split(...)] method
*PRINTF calls [http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html#format(java.lang.String,%20java.lang.Object...) String.format(...)] method

''DesignLabelMapping'' is a ''LabelMapping'' flavour to handle 2<sup>nd</sup> usecase. Now it's empty but there should be a way to define view style used to store label text in notation model [https://bugs.eclipse.org/bugs/show_bug.cgi?id=161593].

==Generator Model==

Two hierarchies describe labels in generator model: descendants of ''GenLabel'' used to express label presentation in context of parent node / link and descendants of ''LabelModelFacet'' that denote label semantic. ''GenLabel'' references ''LabelModelFacet'' by "modelFacet" reference thus linking them together.

===GenLabel===

Basic ''GenLabel'' has "elementIcon" flag copied from graphical definition and "readOnly" flag from the mapping model. ''GenNodeLabel'' and ''GenExternalNodeLabel'' are concrete classes that should be used to represent inner and external node labels respectively. ''GenLinkLabel'' is for the link labels and has "alignment" attribute derived from respective visual facet. ''GenChildLabelNode'' provides the same attributes as ''GenLabel'' but prefixed with "label" word; this class is used for nodes within list compartments.

===LabelModelFacet===

Model facet reflects label usecase:
*'''"feature label"''': ''FeatureLabelModelFacet'' instance; features and patterns are taken from ''FeatureLabelMapping''
*'''"design label"''': ''DesignLabelModelFacet'' instance
*'''"default label" and "custom label"''': no model facet (''null'')
In fact during mapping model to generator model transformation the following rules are obeyed:
*''FeatureLabelMapping'' -> ''FeatureLabelModelFacet''
*''DesignLabelMapping'' -> ''DesignLabelModelFacet''
*''LabelMapping'' -> ''null''

==Pending Requests==

This is a list of enhancements related to GMF labels; hopefully future versions of GMF will implement them:
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=150816 Support "design" labels for nodes backed up with domain element]
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=138179 Allow to define labels based on attributes of referenced objects]
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=161593 Allow to specify notation style for design label mapping]
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=149429 It should be possible to specify whether empty string should be written in domain model when user provides emty string for the label]
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=146818 Provide user feedback when invalid value is provided for the diagram label via direct editing]
*[https://bugs.eclipse.org/bugs/show_bug.cgi?id=146789 Generate resizable labels (optionally)]
Return to GMF Labels.
Retrieved from "http://wiki.eclipse.org/GMF_Labels"
Home Privacy Policy Terms of Use Copyright Agent Contact About Eclipsepedia	Copyright © 2009 The Eclipse Foundation. All Rights Reserved
Eclipse

View source

From Eclipsepedia

Personal tools
