Eclipse 확장 구현하기 (한글)

                
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>

   <extension
         point="org.eclipse.ui.actionSets">
      <actionSet
            label="Sample Action Set"
            visible="true"
            id="SnippetsPlugin.actionSet">
         <menu
               label="Sample &Menu"
               id="sampleMenu">
            <separator
                  name="sampleGroup">
            </separator>
         </menu>
         <action
               label="&Sample Action"
               icon="icons/sample.gif"
               class="snippetsplugin.actions.SnippetAction"
               tooltip="Hello, Eclipse world"
               menubarPath="sampleMenu/sampleGroup"
               toolbarPath="sampleGroup"
               id="snippetsplugin.actions.SnippetAction">
         </action>
      </actionSet>
   </extension>
...
</plugin>

                
public void run(IAction action) {
    MessageDialog.openInformation(
        window.getShell(),
        "SnippetsPlugin Plug-in",
        "Hello, Eclipse world");
}

                
<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.2"?>
<plugin>
...
   <extension
         point="org.eclipse.ui.popupMenus">
      <objectContribution
            objectClass="org.eclipse.core.resources.IFile"
            nameFilter="*.*"
            id="SnippetsPlugin.contribution1">
         <menu
               label="Snippet Submenu"
               path="additions"
               id="SnippetsPlugin.menu1">
            <separator
                  name="group1">
            </separator>
         </menu>
         <action
               label="New Action"
               class="snippetsplugin.popup.actions.SnippetPopupAction"
               menubarPath="SnippetsPlugin.menu1/group1"
               enablesFor="1"
               id="SnippetsPlugin.newAction">
         </action>
      </objectContribution>
   </extension>
...
</plugin>

                
public void run(IAction action) {
    Shell shell = new Shell();
    MessageDialog.openInformation(
        shell,
        "SnippetsPlugin Plug-in",
        "New Action was executed.");
}

                
    public void run(IAction action) {
        MessageDialog.openInformation(
            window.getShell(),
            "SnippetsPlugin Plug-in",
            "Hello, Eclipse world");
    }

                
<menu
      label="Sample &Menu"
      id="sampleMenu">
   <separator
         name="sampleGroup">
   </separator>
</menu>
<action
      label="&Sample Action"
      icon="icons/sample.gif"
      class="snippetsplugin.actions.SnippetAction"
      tooltip="Hello, Eclipse world"
      menubarPath="sampleMenu/sampleGroup"
      toolbarPath="sampleGroup"
      id="snippetsplugin.actions.SnippetAction">
</action>

                
public void createFieldEditors() {
    addField(new DirectoryFieldEditor(PreferenceConstants.P_PATH, 
            "&Directory preference:", getFieldEditorParent()));
    addField(
        new BooleanFieldEditor(
            PreferenceConstants.P_BOOLEAN,
            "&An example of a boolean preference",
            getFieldEditorParent()));

    addField(new RadioGroupFieldEditor(
            PreferenceConstants.P_CHOICE,
        "An example of a multiple-choice preference",
        1,
        new String[][] { { "&Choice 1", "choice1" }, {
            "C&hoice 2", "choice2" }
    }, getFieldEditorParent()));
    addField(
        new StringFieldEditor(PreferenceConstants.P_STRING, 
        "A &text preference:", getFieldEditorParent()));
}

                
    private void makeActions() {
        action1 = new Action() {
            public void run() {
                showMessage("Action 1 executed");
            }
        };
        action1.setText("Action 1");
        action1.setToolTipText("Action 1 tooltip");
        action1.setImageDescriptor(PlatformUI.getWorkbench().getSharedImages().
            getImageDescriptor(ISharedImages.IMG_OBJS_INFO_TSK));
        
        action2 = new Action() {
            public void run() {
                showMessage("Action 2 executed");
            }
        };
        action2.setText("Action 2");
        action2.setToolTipText("Action 2 tooltip");
        action2.setImageDescriptor(PlatformUI.getWorkbench().getSharedImages().
                getImageDescriptor(ISharedImages.IMG_OBJS_INFO_TSK));
        doubleClickAction = new Action() {
            public void run() {
                ISelection selection = viewer.getSelection();
                Object obj = ((IStructuredSelection)selection).getFirstElement();
                showMessage("Double-click detected on "+obj.toString());
            }
        };
    }

                
public interface SnippetProvider {
    
    public String[] getLanguages() throws SnippetProviderException;
    public String[] getCategories(String language) throws SnippetProviderException;
    public SnippetInfo[] getSnippetInfo(String language, String category) 
      throws SnippetProviderException;
    public Snippet getSnippet(SnippetInfo info);
    public void configure(Properties props) throws SnippetProviderConfigurationException;

}

                
    public void configure(Properties props)
            throws SnippetProviderConfigurationException {
        this.properties = props;
        String uriPath = "";
        if (baseUri == null) {
            try {
                uriPath = properties
                        .getProperty("snippetFileProvider.base.directory");

                if (uriPath == null || uriPath.length() == 0) {
                    throw new SnippetProviderConfigurationException(
                            "Please supply a value for property " +
                            "'snippetFileProvider.base.directory'");
                }

                baseUri = new URI(uriPath);

            } catch (URISyntaxException urie) {
                throw new SnippetProviderConfigurationException("URI '"
                        + uriPath + "' incorrectly formatted.", urie);
            }
        }
    }

                
    public String[] getLanguages() throws SnippetProviderException {
        /*
         * The languages will be the high-level directories right underneath the
         * base directory.
         */
        if (languages == null) {

            languages = getFormattedNamesFromLocation(getBaseUri());
        }
        return languages;
    }

                
    public String[] getCategories(String language)
            throws SnippetProviderException {
        try {
            return getFormattedNamesFromLocation(new URI(getBaseUri().getPath()
                    + "/" + language));
        } catch (URISyntaxException e) {
            throw new SnippetProviderException(
                    "Error while loading the categories", e);
        }
    }

                
    public SnippetInfo[] getSnippetInfo(String language, String category)
            throws SnippetProviderException {
        /* Dehydrate the snippet info from the filesystem */
        XMLDecoder decoder = null;
        SnippetInfo[] snippetInfo = null;

        try {
            decoder = new XMLDecoder(new BufferedInputStream(
                    new FileInputStream(buildSnippetInfoPath(getBaseUri(),
                            language, category))));
            snippetInfo = (SnippetInfo[]) decoder.readObject();

        } catch (FileNotFoundException e) {
            throw new SnippetProviderException(
                    "Could not load the snippet info index.", e);
        } finally {
            if (decoder != null) {
                decoder.close();
            }
            decoder = null;
        }

        return snippetInfo;
    }
    
    public Snippet getSnippet(SnippetInfo info) {
        Snippet snippet = null;

        String snippetPath = buildSnippetPath(getBaseUri(), info);

        /* Load the snippet from the file */
        BufferedInputStream stream = null;
        BufferedReader reader = null;
        try {
            stream = new BufferedInputStream(new FileInputStream(snippetPath));
            reader = new BufferedReader(new InputStreamReader(
                    stream));
            String line;
            StringBuffer sb = new StringBuffer();
            while ((line = reader.readLine()) != null) {
                sb.append(line);
                sb.append("\n");
            }
            
            snippet = new Snippet();
            snippet.setContent(sb.toString());
            
            sb = null;
            
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException ioe) {
            // TODO Auto-generated catch block
            ioe.printStackTrace();
        }
        finally
        {
            try {
                if (reader != null) {
                    reader.close();
                }
                if (stream != null) {
                    stream.close();
                }
            } catch (IOException ioe) {
            }
        }

        return snippet;
    }

                
  private void initialize() {

      invisibleRoot = new TreeParent("");

      /*
       * Get the high-level elements from the provider, which are the
       * languages.
       */
      String[] topLevelNodes;

      try {

          Properties properties = new Properties();

          InputStream is = null;

          is = SnippetProviderFactory.class
                  .getResourceAsStream("/SnippetProvider.properties");
          properties.load(is);

          if (is != null) {
              try {
                  is.close();
              } catch (IOException innerE) {
                  throw new SnippetProviderException(
                          "Could not close resource stream.", innerE);
              }
          }

          snippetProvider = SnippetProviderFactory.createInstance();
          snippetProvider.configure(properties);
          topLevelNodes = snippetProvider.getLanguages();

          for (int i = 0; i < topLevelNodes.length; i++) {
              TreeParent parent = new TreeParent(topLevelNodes[i]);

              /* Get the categories for each one of the parents */
              String[] categories = snippetProvider
                      .getCategories(topLevelNodes[i]);
              for (int j = 0; j < categories.length; j++) {
                  TreeParent categoryParent = new TreeParent(
                          categories[j]);

                  /* Now get the snippet names for the categories */
                  SnippetInfo[] info = snippetProvider.getSnippetInfo(
                          topLevelNodes[i], categories[j]);

                  for (int k = 0; k < info.length; k++) {
                      TreeObject leaf = new TreeObject(info[k]);
                      categoryParent.addChild(leaf);
                  }

                  parent.addChild(categoryParent);
              }

              invisibleRoot.addChild(parent);
          }

      } catch (SnippetProviderConfigurationException spce) {
          topLevelNodes = new String[] { "Configuration error:  "
                  + spce.getLocalizedMessage() };
      } catch (SnippetProviderException spe) {
          topLevelNodes = new String[] { "Error while loading snippets" };
      } catch (IOException ioe) {
          topLevelNodes = new String[] { "Error loading configuration properties:"
                  + ioe.getLocalizedMessage() };
      }

  }

                
    class TreeObject implements IAdaptable {
        private SnippetInfo info;

        private TreeParent parent;

        public TreeObject(SnippetInfo info) {
            this.info = info;
        }

        public String getName() {
            return info.getName();
        }

        public void setParent(TreeParent parent) {
            this.parent = parent;
        }

        public TreeParent getParent() {
            return parent;
        }

        public String toString() {
            return getName();
        }

        public SnippetInfo getInfo() {
            return info;
        }

        public Object getAdapter(Class key) {
            return null;
        }
    }

                
    class TreeParent extends TreeObject {
        private ArrayList children;

        private String name;

        public TreeParent(String name) {
            super(null);
            this.name = name;
            children = new ArrayList();
        }

        @SuppressWarnings("unchecked")
        public void addChild(TreeObject child) {
            children.add(child);
            child.setParent(this);
        }

        public void removeChild(TreeObject child) {
            children.remove(child);
            child.setParent(null);
        }

        @SuppressWarnings("unchecked")
        public TreeObject[] getChildren() {
            return (TreeObject[]) children.toArray(new TreeObject[children
                    .size()]);
        }

        public boolean hasChildren() {
            return children.size() > 0;
        }

        @Override
        public String getName() {
            // TODO Auto-generated method stub
            return this.name;
        }

        @Override
        public String toString() {
            return this.getName();
        }
    }

                
<?xml version="1.0" encoding="UTF-8"?> 
<java version="1.5.0_07" class="java.beans.XMLDecoder"> 
 <array class="com.example.plugins.snippets.SnippetInfo" length="1"> 
  <void index="0"> 
   <object class="com.example.plugins.snippets.SnippetInfo"> 
    <void property="category"> 
     <string>Exception_Handling</string> 
    </void> 
    <void property="language"> 
     <string>Java</string> 
    </void> 
    <void property="name"> 
     <string>Exception class</string> 
    </void> 
    <void property="variables"> 
     <array class="java.lang.String" length="3"> 
      <void index="0"> 
       <string>exception.classname</string> 
      </void> 
      <void index="1"> 
       <string>author</string> 
      </void> 
      <void index="2"> 
       <string>package.name</string> 
      </void> 
     </array> 
    </void> 
   </object> 
  </void> 
 </array> 
</java> 

                
+- basedir
 +- Java
 | +- Exception_Handling
 |   +- snippets.info
 |   +- Exception_Class.snippet
 +- XML
   +- Ant_Build_Files
     +- snippets.info
     +- Simple_File.snippet

                
class InsertSnippetAction extends Action {

    @Override
    public void run() {
        MessageDialog.openInformation(
            window.getShell(),
            "SnippetsSample Plug-in",
            "Running Insert Action Now!");
    }
}

                
public class SnippetsView extends ViewPart implements ISelectionListener {
    private TreeViewer viewer;

    private DrillDownAdapter drillDownAdapter;

    private InsertSnippetAction insertAction;

    private SnippetProvider snippetProvider;

    class InsertSnippetAction extends Action {
        // Snipped...
    }

    class TreeObject implements IAdaptable {
        // Snipped...
    }

    class TreeParent extends TreeObject {
        // Snipped...
    }

    class ViewContentProvider implements IStructuredContentProvider,
            ITreeContentProvider {
        private TreeParent invisibleRoot;

        public void inputChanged(Viewer v, Object oldInput, Object newInput) {
        }

        public void dispose() {
        }

        public Object[] getElements(Object parent) {
            if (parent.equals(getViewSite())) {
                if (invisibleRoot == null)
                    initialize();
                return getChildren(invisibleRoot);
            }
            return getChildren(parent);
        }

        public Object getParent(Object child) {
            if (child instanceof TreeObject) {
                return ((TreeObject) child).getParent();
            }
            return null;
        }

        public Object[] getChildren(Object parent) {
            if (parent instanceof TreeParent) {
                return ((TreeParent) parent).getChildren();
            }
            return new Object[0];
        }

        public boolean hasChildren(Object parent) {
            if (parent instanceof TreeParent)
                return ((TreeParent) parent).hasChildren();
            return false;
        }

        private void initialize() {
            // Snipped... see earlier Listing.
        }

    }

    class ViewLabelProvider extends LabelProvider {

        public String getText(Object obj) {
            return obj.toString();
        }

        public Image getImage(Object obj) {
            String imageKey = ISharedImages.IMG_OBJ_ELEMENT;
            if (obj instanceof TreeParent)
                imageKey = ISharedImages.IMG_OBJ_FOLDER;
            return PlatformUI.getWorkbench().getSharedImages().getImage(
                    imageKey);
        }
    }

    class NameSorter extends ViewerSorter {
    }

    /**
     * The constructor.
     */
    public SnippetsView() {
    }

    /**
     * This is a callback that will allow us to create the viewer and initialize
     * it.
     */
    public void createPartControl(Composite parent) {
            viewer = new TreeViewer(parent, SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL);
        drillDownAdapter = new DrillDownAdapter(viewer);
        viewer.setContentProvider(new ViewContentProvider());
        viewer.setLabelProvider(new ViewLabelProvider());
        viewer.setSorter(new NameSorter());
        viewer.setInput(getViewSite());
        // add myself as a global selection listener
        getSite().getPage().addSelectionListener(this);

        // prime the selection
        selectionChanged(null, getSite().getPage().getSelection());
        makeActions();
        hookContextMenu();
        hookDoubleClickAction();
        contributeToActionBars();

    }

    private void hookContextMenu() {
        MenuManager menuMgr = new MenuManager("#PopupMenu");
        menuMgr.setRemoveAllWhenShown(true);
        menuMgr.addMenuListener(new IMenuListener() {
            public void menuAboutToShow(IMenuManager manager) {
                SnippetsView.this.fillContextMenu(manager);
            }
        });
        Menu menu = menuMgr.createContextMenu(viewer.getControl());
        viewer.getControl().setMenu(menu);
        getSite().registerContextMenu(menuMgr, viewer);
    }

    private void contributeToActionBars() {
        IActionBars bars = getViewSite().getActionBars();
        fillLocalPullDown(bars.getMenuManager());
        fillLocalToolBar(bars.getToolBarManager());
    }

    private void fillLocalPullDown(IMenuManager manager) {
        manager.add(insertAction);
        manager.add(new Separator());
    }

    private void fillContextMenu(IMenuManager manager) {
        manager.add(insertAction);
        manager.add(new Separator());
        drillDownAdapter.addNavigationActions(manager);
        // Other plug-ins can contribute there actions here
        manager.add(new Separator(IWorkbenchActionConstants.MB_ADDITIONS));
    }

    private void fillLocalToolBar(IToolBarManager manager) {
        manager.add(insertAction);
        manager.add(new Separator());
        drillDownAdapter.addNavigationActions(manager);
    }

    private void makeActions() {
        
        insertAction = new InsertSnippetAction();
        insertAction.setText("Insert Snippet");
        insertAction.setToolTipText("Inserts the selected snippet");
        insertAction.setImageDescriptor(PlatformUI.getWorkbench()
                .getSharedImages().getImageDescriptor(
                        ISharedImages.IMG_OBJS_INFO_TSK));
    }

    private void hookDoubleClickAction() {
        viewer.addDoubleClickListener(new IDoubleClickListener() {
            public void doubleClick(DoubleClickEvent event) {
                insertAction.run();
            }
        });
    }

    /**
     * Passing the focus request to the viewer's control.
     */
    public void setFocus() {
        viewer.getControl().setFocus();
    }

    public void selectionChanged(IWorkbenchPart part, ISelection selection) {
    }
    
}

                
class InsertSnippetAction extends Action {

    @Override
    public void run() {

        IEditorPart target = getViewSite().getWorkbenchWindow()
                .getActivePage().getActiveEditor();
        if (target != null) {
            ITextEditor textEditor = null;
            if (target instanceof ITextEditor) {
                textEditor = (ITextEditor) target;
                ISelectionProvider sp = textEditor.getSelectionProvider();
                ITextSelection sel = (ITextSelection) sp.getSelection();

                IDocument doc = textEditor.getDocumentProvider()
                        .getDocument(textEditor.getEditorInput());
                try {
                    String text = getMergedSnippetContent();
                    doc.replace(sel.getOffset(), sel.getLength(), text);
                } catch (BadLocationException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}

                
public String getMergedSnippetContent()
{
    String result = "";
    ISelection selection = viewer.getSelection();
    Object obj = ((IStructuredSelection) selection).getFirstElement();

    if (obj instanceof TreeObject) {
        SnippetInfo info = ((TreeObject) obj).getInfo();
        Snippet s = snippetProvider.getSnippet(info);

        SnippetVariablesWizardPage page = new SnippetVariablesWizardPage(
                "", info, s);
        page.setTitle("Snippet Variables");
        page.setDescription("Input the values to replace the template "
                + "variables found in this snippet.");

        // create wizard
        SnippetVariablesWizard wizard = new SnippetVariablesWizard(page);

        // create wizard dialog & launch wizard dialog
        WizardDialog dialog = new WizardDialog(viewer.getControl()
                .getShell(), wizard);
        dialog.open();

        result = s.getMergedContent();
    }
    return result;
}

                
public class SnippetVariablesWizardPage extends WizardPage {

    // Use the Table widget
    // http://www.eclipse.org/swt/widgets/
    // http://help.eclipse.org/help31/nftopic/org.eclipse.platform.doc.isv
/reference/api/org/eclipse/swt/widgets/Table.html
    private Table propertyTable;
    private TableViewer tableViewer;
    private SnippetInfo snippetInfo;
    private Snippet snippet;
    private static final String[] columnNames = new String[]{"property", "value"};
    private SnippetVariableValue[] variables;

    class SnippetVariableValue
    {
  		// Snipped... see Listing 24
    }
    
    class SnippetVariableContentProvider implements IStructuredContentProvider {
		// Snipped... see Listing 25
    }
    
    class SnippetVariableLabelProvider extends LabelProvider implements
            ITableLabelProvider {
 		// Snipped... see Listing 26
    }
    
    class SnippetVariableCellModifier implements ICellModifier {
		// Snipped... see Listing 27
    }
    
    private SnippetVariableValue[] initializeData(SnippetInfo info)
    {
     SnippetVariableValue[] result = new SnippetVariableValue[info.getVariables().length];
        for (int i = 0; i < info.getVariables().length; i++) {
            result[i] = new SnippetVariablesWizardPage.SnippetVariableValue(
                info.getVariables()[i]);
        }
        return result;
    }

    public SnippetVariablesWizardPage(String pageName, 
        SnippetInfo info, Snippet snippet) {
        super(pageName);
        this.snippetInfo = info;
        this.snippet = snippet;
        this.variables = initializeData(this.snippetInfo);
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.eclipse.jface.dialogs.IDialogPage#createControl(
     * org.eclipse.swt.widgets.Composite)
     */
    public void createControl(Composite parent) {
        // create main composite & set layout
        Composite container = new Composite(parent, SWT.NONE);
        container.setLayout(new FillLayout());
        container.setLayoutData(new GridData(GridData.FILL_BOTH));

        // titleText = new Text(mainComposite, SWT.BORDER | SWT.SINGLE);
        propertyTable = new Table(container, SWT.BORDER | SWT.SINGLE);
        propertyTable.setHeaderVisible(true);
        propertyTable.setLinesVisible(true);
        int colWidth = 160;
        TableColumn column = new TableColumn(propertyTable, SWT.LEFT, 0);
        column.setText("Property Name");
        column.setWidth(colWidth);
        // Second column
        column = new TableColumn(propertyTable, SWT.LEFT, 1);
        column.setText("Value");
        column.setWidth(colWidth);
        
        // Iterate through the variables in the snippet info and add them to the 
        // table.
        tableViewer = new TableViewer(propertyTable);
        tableViewer.setUseHashlookup(true);
        tableViewer.setColumnProperties(columnNames);
        CellEditor[] editors = new CellEditor[columnNames.length];
        
        TextCellEditor textEditor = new TextCellEditor(propertyTable);
        ((Text) textEditor.getControl()).setTextLimit(60);
        editors[0] = textEditor;
        
        textEditor = new TextCellEditor(propertyTable);
        ((Text) textEditor.getControl()).setTextLimit(60);
        editors[1] = textEditor;
        
        tableViewer.setCellEditors(editors);
        tableViewer.setCellModifier(new SnippetVariableCellModifier());
        
        tableViewer.setContentProvider(new SnippetVariableContentProvider());
        tableViewer.setLabelProvider(new SnippetVariableLabelProvider());
        tableViewer.setInput(this.variables);

        // page setting
        setControl(container);
        setPageComplete(true);

    }
    
    public void updateSnippet()
    {
        /* Get the values from the table */
        HashMap map = createMap(variables);
        snippet.mergeContent(map);
    }
    
    @SuppressWarnings("unchecked")
    private HashMap createMap(SnippetVariableValue[] variables)
    {
        HashMap map = new HashMap();
        
        for (int i = 0; i < variables.length; i++)
        {
            map.put(variables[i].property, variables[i].value);
        }
        
        return map;
    }

}

                
class SnippetVariableValue
{
    public String property;
    public String value;
    
    public SnippetVariableValue(String property)
    {
        this.property = property;
        this.value = "";
    }
}

                
class SnippetVariableContentProvider implements IStructuredContentProvider {
    public void dispose() {
    }

    public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
    }

    public Object[] getElements(Object parent) {
        return variables;
    }
}

                
class SnippetVariableLabelProvider extends LabelProvider implements
        ITableLabelProvider {
    public Image getColumnImage(Object element, int columnIndex) {
        return null;
    }

    public String getColumnText(Object element, int columnIndex) {
        SnippetVariableValue variable = (SnippetVariableValue) element;
        if (columnIndex == 0) {
            return variable.property;
        } else if (columnIndex == 1) {
            return (variable.value != null) ? variable.value : "Type value";
        } else {
            return "";
        }
    }
}

                
class SnippetVariableCellModifier implements ICellModifier {

    public boolean canModify(Object element, String property) {
        return (!property.equals("property"));
    }

    public Object getValue(Object element, String property) {
        Object result;
        SnippetVariableValue variable = (SnippetVariableValue) element;

        if (property.equals("property")) {
            result = variable.property;
        } else if (property.equals("value")) {
            result = variable.value;
        } else {
            result = "";
        }

        return result;
    }

    public void modify(Object element, String property, Object value) {
        TableItem item = (TableItem) element;
        SnippetVariableValue variable = (SnippetVariableValue) item
                .getData();
        if (property.equals("value")) {
            variable.value = (value != null) ? value.toString() : "";
        }
        tableViewer.update(variable, null);
    }
    }

                
public class SnippetVariablesWizard extends Wizard {
    
    public SnippetVariablesWizard(SnippetVariablesWizardPage page)
    {
        addPage(page);
    }

    @Override
    public boolean performFinish() {
                      SnippetVariablesWizardPage page = 
                          (SnippetVariablesWizardPage)getPages()[0];
        page.updateSnippet();
        return true;
    }

}

                
class SnippetDragDropListener implements TransferDragSourceListener {

    public Transfer getTransfer() {
        return TextTransfer.getInstance();
    }

    public void dragFinished(DragSourceEvent event) {
        // There is nothing to clean up or do.
    }

    public void dragSetData(DragSourceEvent event) {

        ISelection selection = viewer.getSelection();
                      Object obj = ((IStructuredSelection) selection).getFirstElement();

        if (obj instanceof TreeObject) {
            event.data = getMergedSnippetContent();
        }
    }

    public void dragStart(DragSourceEvent event) {
        // Always enabled, so don't do anything on the start.
    }

}

                
    public void createPartControl(Composite parent) {
        viewer = new TreeViewer(parent, SWT.MULTI | 
            SWT.H_SCROLL | SWT.V_SCROLL);
        drillDownAdapter = new DrillDownAdapter(viewer);
        viewer.setContentProvider(new ViewContentProvider());
        viewer.setLabelProvider(new ViewLabelProvider());
        viewer.setSorter(new NameSorter());
        viewer.setInput(getViewSite());
        // add myself as a global selection listener
        getSite().getPage().addSelectionListener(this);

        // prime the selection
        selectionChanged(null, getSite().getPage().getSelection());
        makeActions();
        hookContextMenu();
        hookDoubleClickAction();
        contributeToActionBars();

        DelegatingDragAdapter dragAdapter = new DelegatingDragAdapter();
        SnippetDragDropListener dragDropListener = 
            new SnippetDragDropListener();
        dragAdapter.addDragSourceListener(
            (TransferDragSourceListener) dragDropListener);
        viewer.addDragSupport(DND.DROP_COPY | DND.DROP_MOVE, 
            dragAdapter.getTransfers(), dragAdapter);

    }

                
public void createFieldEditors() {
    addField(new StringFieldEditor(PreferenceConstants.P_CLASS,
            "Snippet &Implementation Class:", getFieldEditorParent()));
    addField(new StringFieldEditor(PreferenceConstants.P_SNIPPET_REPOS_LOC,
            "&Snippet Repository Path:", getFieldEditorParent()));
}