TypingRunDetector observes
- * TypingRun events. A typing run is a sequence of similar text
- * modifications, such as inserting or deleting single characters.
- *
- * Listeners are informed about the start and end of a TypingRun.
- *
type.
- *
- * @param type
- * the ChangeType of the new change
- * @param nextOffset
- * the offset of the next change in a typing run
- */
- public Change(ChangeType type, int nextOffset) {
- fType = type;
- fNextOffset = nextOffset;
- }
-
- /**
- * Returns true if the receiver can extend the typing
- * range the last change of which is described by change.
- *
- * @param change
- * the last change in a typing run
- * @return true if the receiver is a valid extension to
- * change,false otherwise
- */
- public boolean canFollow(Change change) {
- if (fType == TypingRun.NO_CHANGE)
- return true;
- else if (fType.equals(TypingRun.UNKNOWN))
- return false;
- if (fType.equals(change.fType)) {
- if (fType == TypingRun.DELETE)
- return fNextOffset == change.fNextOffset - 1;
- else if (fType == TypingRun.INSERT)
- return fNextOffset == change.fNextOffset + 1;
- else if (fType == TypingRun.OVERTYPE)
- return fNextOffset == change.fNextOffset + 1;
- else if (fType == TypingRun.SELECTION)
- return true;
- }
- return false;
- }
-
- /**
- * Returns true if the receiver describes a text
- * modification, false if it describes a focus /
- * selection change.
- *
- * @return true if the receiver is a text modification
- */
- public boolean isModification() {
- return fType.isModification();
- }
-
- /*
- * @see java.lang.Object#toString()
- */
- public String toString() {
- return fType.toString() + "@" + fNextOffset; //$NON-NLS-1$
- }
-
- /**
- * Returns the change type of this change.
- *
- * @return the change type of this change
- */
- public ChangeType getType() {
- return fType;
- }
- }
-
- /**
- * Observes any events that modify the content of the document displayed in
- * the editor. Since text events may start a new run, this listener is
- * always registered if the detector is connected.
- */
- private class TextListener implements ITextListener {
-
- /*
- * @see org.eclipse.jface.text.ITextListener#textChanged(org.eclipse.jface.text.TextEvent)
- */
- public void textChanged(TextEvent event) {
- handleTextChanged(event);
- }
- }
-
- /**
- * Observes non-modifying events that will end a run, such as clicking into
- * the editor, moving the caret, and the editor losing focus. These events
- * can never start a run, therefore this listener is only registered if
- * there is an ongoing run.
- */
- private class SelectionListener implements MouseListener, KeyListener,
- FocusListener {
-
- /*
- * @see org.eclipse.swt.events.FocusListener#focusGained(org.eclipse.swt.events.FocusEvent)
- */
- public void focusGained(FocusEvent e) {
- handleSelectionChanged();
- }
-
- /*
- * @see org.eclipse.swt.events.FocusListener#focusLost(org.eclipse.swt.events.FocusEvent)
- */
- public void focusLost(FocusEvent e) {
- }
-
- /*
- * @see MouseListener#mouseDoubleClick
- */
- public void mouseDoubleClick(MouseEvent e) {
- }
-
- /*
- * If the right mouse button is pressed, the current editing command is
- * closed
- *
- * @see MouseListener#mouseDown
- */
- public void mouseDown(MouseEvent e) {
- if (e.button == 1)
- handleSelectionChanged();
- }
-
- /*
- * @see MouseListener#mouseUp
- */
- public void mouseUp(MouseEvent e) {
- }
-
- /*
- * @see KeyListener#keyPressed
- */
- public void keyReleased(KeyEvent e) {
- }
-
- /*
- * On cursor keys, the current editing command is closed
- *
- * @see KeyListener#keyPressed
- */
- public void keyPressed(KeyEvent e) {
- switch (e.keyCode) {
- case SWT.ARROW_UP:
- case SWT.ARROW_DOWN:
- case SWT.ARROW_LEFT:
- case SWT.ARROW_RIGHT:
- case SWT.END:
- case SWT.HOME:
- case SWT.PAGE_DOWN:
- case SWT.PAGE_UP:
- handleSelectionChanged();
- break;
- }
- }
- }
-
- /** The listeners. */
- private final Set fListeners = new HashSet();
-
- /**
- * The viewer we work upon. Set to null in
- * uninstall.
- */
- private ITextViewer fViewer;
-
- /** The text event listener. */
- private final TextListener fTextListener = new TextListener();
-
- /**
- * The selection listener. Set to null when no run is active.
- */
- private SelectionListener fSelectionListener;
-
- /* state variables */
-
- /** The most recently observed change. Never null. */
- private Change fLastChange;
-
- /** The current run, or null if there is none. */
- private TypingRun fRun;
-
- /**
- * Installs the receiver with a text viewer.
- *
- * @param viewer
- * the viewer to install on
- */
- public void install(ITextViewer viewer) {
- Assert.isLegal(viewer != null);
- fViewer = viewer;
- connect();
- }
-
- /**
- * Initializes the state variables and registers any permanent listeners.
- */
- private void connect() {
- if (fViewer != null) {
- fLastChange = new Change(TypingRun.UNKNOWN, -1);
- fRun = null;
- fSelectionListener = null;
- fViewer.addTextListener(fTextListener);
- }
- }
-
- /**
- * Uninstalls the receiver and removes all listeners. install()
- * must be called for events to be generated.
- */
- public void uninstall() {
- if (fViewer != null) {
- fListeners.clear();
- disconnect();
- fViewer = null;
- }
- }
-
- /**
- * Disconnects any registered listeners.
- */
- private void disconnect() {
- fViewer.removeTextListener(fTextListener);
- ensureSelectionListenerRemoved();
- }
-
- /**
- * Adds a listener for TypingRun events. Repeatedly adding
- * the same listener instance has no effect. Listeners may be added even if
- * the receiver is neither connected nor installed.
- *
- * @param listener
- * the listener add
- */
- public void addTypingRunListener(ITypingRunListener listener) {
- Assert.isLegal(listener != null);
- fListeners.add(listener);
- if (fListeners.size() == 1)
- connect();
- }
-
- /**
- * Removes the listener from this manager. If listener is not
- * registered with the receiver, nothing happens.
- *
- * @param listener
- * the listener to remove, or null
- */
- public void removeTypingRunListener(ITypingRunListener listener) {
- fListeners.remove(listener);
- if (fListeners.size() == 0)
- disconnect();
- }
-
- /**
- * Handles an incoming text event.
- *
- * @param event
- * the text event that describes the text modification
- */
- void handleTextChanged(TextEvent event) {
- Change type = computeChange(event);
- handleChange(type);
- }
-
- /**
- * Computes the change abstraction given a text event.
- *
- * @param event
- * the text event to analyze
- * @return a change object describing the event
- */
- private Change computeChange(TextEvent event) {
- DocumentEvent e = event.getDocumentEvent();
- if (e == null)
- return new Change(TypingRun.NO_CHANGE, -1);
-
- int start = e.getOffset();
- int end = e.getOffset() + e.getLength();
- String newText = e.getText();
- if (newText == null)
- newText = new String();
-
- if (start == end) {
- // no replace / delete / overwrite
- if (newText.length() == 1)
- return new Change(TypingRun.INSERT, end + 1);
- } else if (start == end - 1) {
- if (newText.length() == 1)
- return new Change(TypingRun.OVERTYPE, end);
- if (newText.length() == 0)
- return new Change(TypingRun.DELETE, start);
- }
-
- return new Change(TypingRun.UNKNOWN, -1);
- }
-
- /**
- * Handles an incoming selection event.
- */
- void handleSelectionChanged() {
- handleChange(new Change(TypingRun.SELECTION, -1));
- }
-
- /**
- * State machine. Changes state given the current state and the incoming
- * change.
- *
- * @param change
- * the incoming change
- */
- private void handleChange(Change change) {
- if (change.getType() == TypingRun.NO_CHANGE)
- return;
-
- if (DEBUG)
- System.err.println("Last change: " + fLastChange); //$NON-NLS-1$
-
- if (!change.canFollow(fLastChange))
- endIfStarted(change);
- fLastChange = change;
- if (change.isModification())
- startOrContinue();
-
- if (DEBUG)
- System.err.println("New change: " + change); //$NON-NLS-1$
- }
-
- /**
- * Starts a new run if there is none and informs all listeners. If there
- * already is a run, nothing happens.
- */
- private void startOrContinue() {
- if (!hasRun()) {
- if (DEBUG)
- System.err.println("+Start run"); //$NON-NLS-1$
- fRun = new TypingRun(fLastChange.getType());
- ensureSelectionListenerAdded();
- fireRunBegun(fRun);
- }
- }
-
- /**
- * Returns true if there is an active run, false
- * otherwise.
- *
- * @return true if there is an active run, false
- * otherwise
- */
- private boolean hasRun() {
- return fRun != null;
- }
-
- /**
- * Ends any active run and informs all listeners. If there is none, nothing
- * happens.
- *
- * @param change
- * the change that triggered ending the active run
- */
- private void endIfStarted(Change change) {
- if (hasRun()) {
- ensureSelectionListenerRemoved();
- if (DEBUG)
- System.err.println("-End run"); //$NON-NLS-1$
- fireRunEnded(fRun, change.getType());
- fRun = null;
- }
- }
-
- /**
- * Adds the selection listener to the text widget underlying the viewer, if
- * not already done.
- */
- private void ensureSelectionListenerAdded() {
- if (fSelectionListener == null) {
- fSelectionListener = new SelectionListener();
- StyledText textWidget = fViewer.getTextWidget();
- textWidget.addFocusListener(fSelectionListener);
- textWidget.addKeyListener(fSelectionListener);
- textWidget.addMouseListener(fSelectionListener);
- }
- }
-
- /**
- * If there is a selection listener, it is removed from the text widget
- * underlying the viewer.
- */
- private void ensureSelectionListenerRemoved() {
- if (fSelectionListener != null) {
- StyledText textWidget = fViewer.getTextWidget();
- textWidget.removeFocusListener(fSelectionListener);
- textWidget.removeKeyListener(fSelectionListener);
- textWidget.removeMouseListener(fSelectionListener);
- fSelectionListener = null;
- }
- }
-
- /**
- * Informs all listeners about a newly started TypingRun.
- *
- * @param run
- * the new run
- */
- private void fireRunBegun(TypingRun run) {
- List listeners = new ArrayList(fListeners);
- for (Iterator it = listeners.iterator(); it.hasNext();) {
- ITypingRunListener listener = (ITypingRunListener) it.next();
- listener.typingRunStarted(fRun);
- }
- }
-
- /**
- * Informs all listeners about an ended TypingRun.
- *
- * @param run
- * the previously active run
- * @param reason
- * the type of change that caused the run to be ended
- */
- private void fireRunEnded(TypingRun run, ChangeType reason) {
- List listeners = new ArrayList(fListeners);
- for (Iterator it = listeners.iterator(); it.hasNext();) {
- ITypingRunListener listener = (ITypingRunListener) it.next();
- listener.typingRunEnded(fRun, reason);
- }
- }
-}