SmartBackspaceManager will manage
- * the specfications and execute the contained TextEdits when
- * backspace is pressed at the given offset and the specification is still
- * valid.
- * - * Undo specifications are removed after a number of typing runs. - *
- * - * @since 3.0 - */ -public class SmartBackspaceManager { - /* independent of JDT - may be moved to jface.text */ - - /** - * An undo specification describes the change that should be executed if - * backspace is pressed at its trigger offset. - * - * @since 3.0 - */ - public static final class UndoSpec { - private final int triggerOffset; - - private final IRegion selection; - - private final TextEdit[] undoEdits; - - private final UndoSpec child; - - int lives; - - /** - * Creates a new spec. A specification consists of a number of - *TextEdit s that will be executed when backspace is
- * pressed at triggerOffset. The spec will be removed
- * when it is executed, or if more than lives
- * TypingRuns
- * have ended after registering the spec.
- *
- * Optionally, a child specification can be registered. After executing
- * the spec, the child spec will be registered with the manager. This
- * allows to create chains of UndoSpecs that will be
- * executed upon repeated pressing of backspace.
- *
TextEdit s to perform when executing
- * the spec
- * @param lives
- * the number of TypingRun s before removing
- * the spec
- * @param child
- * a child specification that will be registered after
- * executing this spec, or null
- */
- public UndoSpec(int triggerOffset, IRegion selection, TextEdit[] edits,
- int lives, UndoSpec child) {
- Assert.isLegal(triggerOffset >= 0);
- Assert.isLegal(selection != null);
- Assert.isLegal(lives >= 0);
- Assert.isLegal(edits != null);
- Assert.isLegal(edits.length > 0);
- for (int i = 0; i < edits.length; i++) {
- Assert.isLegal(edits[i] != null);
- }
-
- this.triggerOffset = triggerOffset;
- this.selection = selection;
- this.undoEdits = edits;
- this.lives = lives;
- this.child = child;
- }
- }
-
- private class BackspaceListener implements VerifyKeyListener {
-
- /*
- * @see org.eclipse.swt.custom.VerifyKeyListener#verifyKey(org.eclipse.swt.events.VerifyEvent)
- */
- public void verifyKey(VerifyEvent event) {
- if (fViewer != null && isBackspace(event)) {
- int offset = getCaretOffset();
- UndoSpec spec = removeEdit(offset);
- if (spec != null) {
- try {
- beginChange();
- for (int i = 0; i < spec.undoEdits.length; i++) {
- spec.undoEdits[i].apply(getDocument(),
- TextEdit.UPDATE_REGIONS);
- }
- fViewer.setSelectedRange(spec.selection.getOffset(),
- spec.selection.getLength());
- if (spec.child != null)
- register(spec.child);
- } catch (MalformedTreeException e) {
- // fall back to standard bs
- return;
- } catch (BadLocationException e) {
- // fall back to standard bs
- return;
- } finally {
- endChange();
- }
- event.doit = false;
- }
-
- }
- }
-
- private void beginChange() {
- ITextViewer viewer = fViewer;
- if (viewer instanceof TextViewer) {
- TextViewer v = (TextViewer) viewer;
- v.getRewriteTarget().beginCompoundChange();
- v.setRedraw(false);
- }
- }
-
- private void endChange() {
- ITextViewer viewer = fViewer;
- if (viewer instanceof TextViewer) {
- TextViewer v = (TextViewer) viewer;
- v.getRewriteTarget().endCompoundChange();
- v.setRedraw(true);
- }
- }
-
- private boolean isBackspace(VerifyEvent event) {
- return event.doit == true && event.character == SWT.BS
- && event.stateMask == 0;
- }
-
- private int getCaretOffset() {
- ITextViewer viewer = fViewer;
- Point point = viewer.getSelectedRange();
- return point.x;
- }
-
- }
-
- private ITextViewer fViewer;
-
- private BackspaceListener fBackspaceListener;
-
- private Map fSpecs;
-
- private TypingRunDetector fRunDetector;
-
- private ITypingRunListener fRunListener;
-
- /**
- * Registers an undo specification with this manager.
- *
- * @param spec
- * the specification to register
- * @throws IllegalStateException
- * if the manager is not installed
- */
- public void register(UndoSpec spec) {
- if (fViewer == null)
- throw new IllegalStateException();
-
- ensureListenerInstalled();
- addEdit(spec);
- }
-
- private void addEdit(UndoSpec spec) {
- Integer i = new Integer(spec.triggerOffset);
- fSpecs.put(i, spec);
- }
-
- private UndoSpec removeEdit(int offset) {
- Integer i = new Integer(offset);
- UndoSpec spec = (UndoSpec) fSpecs.remove(i);
- return spec;
- }
-
- private void ensureListenerInstalled() {
- if (fBackspaceListener == null) {
- fBackspaceListener = new BackspaceListener();
- ITextViewer viewer = fViewer;
- if (viewer instanceof ITextViewerExtension)
- ((ITextViewerExtension) viewer)
- .prependVerifyKeyListener(fBackspaceListener);
- else
- viewer.getTextWidget().addVerifyKeyListener(fBackspaceListener);
- }
- }
-
- private void ensureListenerRemoved() {
- if (fBackspaceListener != null) {
- ITextViewer viewer = fViewer;
- if (viewer instanceof ITextViewerExtension)
- ((ITextViewerExtension) viewer)
- .removeVerifyKeyListener(fBackspaceListener);
- else
- viewer.getTextWidget().removeVerifyKeyListener(
- fBackspaceListener);
- fBackspaceListener = null;
- }
- }
-
- private IDocument getDocument() {
- return fViewer.getDocument();
- }
-
- /**
- * Installs the receiver on a text viewer.
- *
- * @param viewer
- */
- public void install(ITextViewer viewer) {
- Assert.isLegal(viewer != null);
-
- fViewer = viewer;
- fSpecs = new HashMap();
- fRunDetector = new TypingRunDetector();
- fRunDetector.install(viewer);
- fRunListener = new ITypingRunListener() {
-
- /*
- * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunStarted(org.eclipse.jface.text.TypingRunDetector.TypingRun)
- */
- public void typingRunStarted(TypingRun run) {
- }
-
- /*
- * @see org.eclipse.jface.text.TypingRunDetector.ITypingRunListener#typingRunEnded(org.eclipse.jface.text.TypingRunDetector.TypingRun)
- */
- public void typingRunEnded(TypingRun run, ChangeType reason) {
- if (reason == TypingRun.SELECTION)
- fSpecs.clear();
- else
- prune();
- }
- };
- fRunDetector.addTypingRunListener(fRunListener);
- }
-
- private void prune() {
- for (Iterator it = fSpecs.values().iterator(); it.hasNext();) {
- UndoSpec spec = (UndoSpec) it.next();
- if (--spec.lives < 0)
- it.remove();
- }
- }
-
- /**
- * Uninstalls the receiver. No undo specifications may be registered on an
- * uninstalled manager.
- */
- public void uninstall() {
- if (fViewer != null) {
- fRunDetector.removeTypingRunListener(fRunListener);
- fRunDetector.uninstall();
- fRunDetector = null;
- ensureListenerRemoved();
- fViewer = null;
- }
- }
-}