HaddockDocumentPreviousAction.java

package net.sf.eclipsefp.haskell.ui.internal.editors.haskell.actions;

import java.util.ResourceBundle;
import net.sf.eclipsefp.haskell.ui.editor.actions.IEditorActionDefinitionIds;
import net.sf.eclipsefp.haskell.ui.internal.editors.haskell.HaskellEditor;
import net.sf.eclipsefp.haskell.ui.internal.util.UITexts;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.ITextSelection;
import org.eclipse.jface.text.TextSelection;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.ISelectionProvider;
import org.eclipse.ui.texteditor.ITextEditor;
import org.eclipse.ui.texteditor.TextEditorAction;

/** Implements Haddock -> Document Previous item/element */
public final class HaddockDocumentPreviousAction extends TextEditorAction {
  /** The Haddock previous item documentation marker */
  private static final String PREVDOC_MARKER = " -- ^ ";
  /** The documentation for the user to replace */
  static final String USER_REPLACES = UITexts.HaddockDocumentation_user_replaces;

  /** Default constructor */
  public HaddockDocumentPreviousAction(final ResourceBundle bundle, final String prefix, final ITextEditor editor) {
    super(bundle, prefix, editor);
    setId( HaskellEditor.HADDOCK_DOCUMENT_PREVIOUS_ACTION );
    setActionDefinitionId( IEditorActionDefinitionIds.HADDOCK_PREVIOUS );
  }

  @Override
  public void run() {
    // Go to the end of the line in the editor's document, add the "-- ^ " code:
    ITextEditor editor = getTextEditor();

    if (editor instanceof HaskellEditor) {
      HaskellEditor hEditor = ( HaskellEditor ) editor;
      IDocument doc = hEditor.getDocument();

      ISelectionProvider selectionProvider = hEditor.getSelectionProvider();
      ISelection selection = selectionProvider.getSelection();
      if (selection instanceof ITextSelection) {
        ITextSelection textSelection = ( ITextSelection )selection;
        int offset = textSelection.getOffset();

        if (offset > -1) {
          try {
            IRegion currentLine = doc.getLineInformationOfOffset( offset );
            int endOfLineOffset = currentLine.getOffset() + currentLine.getLength();

            doc.replace(endOfLineOffset, 0, PREVDOC_MARKER.concat(USER_REPLACES));

            ITextSelection newCursor = new TextSelection( doc, endOfLineOffset + PREVDOC_MARKER.length(), USER_REPLACES.length() );
            selectionProvider.setSelection( newCursor );
          } catch( BadLocationException ex ) {
            // Ignore and continue...
          }
        }
      }
    }
  }

  @Override
  public boolean isEnabled() {
    return true;
  }
}