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| <h1>Providing Custom Functionality</h1> |
| <p>If the editor developer wants to add some editor specific functionality (e.g. |
| context menu actions which can change the business and/or the pictogram model) the |
| predefined features are not enough. In this case we need a more general feature. |
| For that purpose the framework provides a custom feature. Examples for a custom |
| feature are rename, change color, check out, etc.</p> |
| <h2>Create a Custom Feature</h2> |
| <p>A custom feature has to implement the interface |
| <a href="../../../javadoc/org/eclipse/graphiti/features/custom/ICustomFeature.html"> |
| ICustomFeature</a>. Instead of implementing it directly it should extend one of |
| the available base classes. In this example we extend the base class |
| <a href="../../../javadoc/org/eclipse/graphiti/features/custom/AbstractCustomFeature.html"> |
| AbstractCustomFeature</a>.</p> |
| <p>In this case we have to implement/overwrite 4 methods:</p> |
| <ul> |
| <li>The method |
| <a href="../../../javadoc/org/eclipse/graphiti/features/custom/ICustomFeature.html#canExecute(org.eclipse.graphiti.features.context.ICustomContext)"> |
| canExecute</a> has to check whether the custom feature can be executed on the |
| current pictogram element of the given context.</li> |
| <li>The method |
| <a href="../../../javadoc/org/eclipse/graphiti/features/custom/ICustomFeature.html#execute(org.eclipse.graphiti.features.context.ICustomContext)"> |
| execute</a> has to perform the custom specific stuff.</li> |
| <li>These two methods receive a custom context as parameter. Interface |
| <a href="../../../javadoc/org/eclipse/graphiti/features/context/ICustomContext.html"> |
| ICostomContext</a> provides the inner pictogram element and the inner graphics |
| algorithm additionally to the (selected) pictogram element. These are the inner |
| elements the mouse pointer is placed / clicked on.</li> |
| <li>Currently only custom features receive the information on the inner elements |
| additionally to the selected/selectable ones. </li> |
| </ul> |
| <p>The methods |
| <a href="../../../javadoc/org/eclipse/graphiti/IName.html#getName()">getName</a> |
| / |
| <a href="../../../javadoc/org/eclipse/graphiti/IDescription.html#getDescription()"> |
| getDescription</a> have to return the information for the UI representation.</p> |
| <p>In this example we want to implement a custom feature which opens a popup-dialog |
| to change the EClass name. This custom feature should be available and enabled in |
| the context menu if exactly one EClass is selected.</p> |
| <p>You can see the complete implementation of the custom feature here:</p> |
| <!-- Begin code ------------------------------------------------------------------------------- --> |
| <p> </p> |
| <div class="literallayout"> |
| <div class="incode"> |
| <p class="code"><span class="keyword">package </span>org.eclipse.graphiti.examples.tutorial.features;<br> <br> |
| <span class="keyword">public class</span> TutorialRenameEClassFeature extends |
| AbstractCustomFeature {<br> <br> |
| <span class="keyword">private boolean</span> <span class="string">hasDoneChanges |
| </span>= <span class="keyword">false</span>;<br> |
| <br> <span class="keyword">public </span>TutorialRenameEClassFeature(IFeatureProvider |
| fp) {<br> |
| <span class="keyword">super</span>(fp);<br> }<br> <br> |
| @Override<br> <span class="keyword">public </span>String |
| getName() {<br> |
| <span class="keyword">return </span><span class="string">"Rename EClass"</span>;<br> |
| }<br> <br> @Override<br> |
| <span class="keyword">public </span>String getDescription() {<br> |
| <span class="keyword">return </span><span class="string">"Change the name |
| of the EClass"</span>;<br> }<br> <br> |
| @Override<br> <span class="keyword"> public boolean</span> |
| canExecute(ICustomContext context) {<br> |
| <span class="comment">// allow rename if exactly one pictogram element</span><br> |
| <span class="comment">// representing a EClass is selected</span><br> |
| <span class="keyword">boolean </span>ret = <span class="keyword">false</span>;<br> |
| PictogramElement[] pes = context.getPictogramElements();<br> |
| <span class="keyword">if</span> (pes != <span class="keyword">null |
| </span>&& pes.<span class="string">length </span>== 1) {<br> |
| Object bo = getBusinessObjectForPictogramElement(pes[0]);<br> |
| <span class="keyword">if </span>(bo <span class="keyword">instanceof |
| </span>EClass) {<br> |
| ret = <span class="keyword">true</span>;<br> |
| }<br> }<br> |
| <span class="keyword">return </span>ret;<br> }<br> <br> |
| @Override<br> <span class="keyword">public </span>void |
| execute(ICustomContext context) {<br> |
| PictogramElement[] pes = context.getPictogramElements();<br> |
| <span class="keyword">if</span> (pes != null && pes.<span class="string">length |
| </span>== 1) {<br> |
| Object bo = getBusinessObjectForPictogramElement(pes[0]);<br> |
| if (bo <span class="keyword">instanceof </span>EClass) {<br> |
| EClass eClass = (EClass) bo;<br> |
| String currentName = eClass.getName();<br> |
| <span class="comment">// ask user for a new class name</span><br> |
| String newName = ExampleUtil.askString(getName(), getDescription(),<br> |
| currentName);<br> |
| <span class="keyword">if </span>(newName != <span class="keyword">null |
| </span>&& !newName.equals(currentName)) {<br> |
| <span class="keyword">this</span>.<span class="string">hasDoneChanges |
| </span>= <span class="keyword">true</span>;<br> |
| eClass.setName(newName);<br> |
| }<br> |
| }<br> }<br> |
| }<br> <br> @Override<br> |
| <span class="keyword">public boolean</span> hasDoneChanges() {<br> |
| <span class="keyword">return this</span>.<span class="string">hasDoneChanges</span>;<br> |
| }<br>}<br></p> |
| </div> |
| </div> |
| <p> </p> |
| <!-- End code ------------------------------------------------------------------------------- --> |
| <p>Additionally the feature provider has to deliver our newly created custom feature |
| (overwrite the method |
| <a href="../../../javadoc/org/eclipse/graphiti/features/IFeatureProvider.html#getCustomFeatures(org.eclipse.graphiti.features.context.ICustomContext)"> |
| getCustomFeatures</a>). </p> |
| <p>This implementation can be seen here:</p> |
| <!-- End code ------------------------------------------------------------------------------- --> |
| <p> </p> |
| <div class="literallayout"> |
| <div class="incode"> |
| <p class="code">@Override<br><span class="keyword">public </span>ICustomFeature[] |
| getCustomFeatures(ICustomContext context) {<br> |
| <span class="keyword">return new</span> ICustomFeature[] { |
| <span class="keyword">new </span>TutorialRenameEClassFeature(<span class="keyword">this</span>) |
| };<br>} </p> |
| </div> |
| </div> |
| <p> </p> |
| <!-- End code ------------------------------------------------------------------------------- --> |
| <h2>Test: Rename a EClass with a Custom Popup-Dialog</h2> |
| <p>Now start the editor and test this new custom feature:</p> |
| <ol> |
| <li>create or open a diagram </li> |
| <li>create a new EClass "A"</li> |
| <li>open the context menu on this newly created EClass; choose "Rename EClass"</li> |
| <li>rename this EClass to "B"</li> |
| <li>the diagram will be updated automatically with new class name</li> |
| </ol> |
| <p> </p> |
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