| /*=============================================================================# |
| # Copyright (c) 2007, 2019 Stephan Wahlbrink and others. |
| # |
| # This program and the accompanying materials are made available under the |
| # terms of the Eclipse Public License 2.0 which is available at |
| # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0 |
| # which is available at https://www.apache.org/licenses/LICENSE-2.0. |
| # |
| # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0 |
| # |
| # Contributors: |
| # Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation |
| #=============================================================================*/ |
| |
| package org.eclipse.statet.ltk.ui.sourceediting; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.eclipse.jface.text.IRegion; |
| import org.eclipse.jface.viewers.ISelectionChangedListener; |
| import org.eclipse.jface.viewers.SelectionChangedEvent; |
| import org.eclipse.ui.texteditor.IUpdate; |
| |
| import org.eclipse.statet.jcommons.collections.CopyOnWriteIdentityListSet; |
| |
| |
| /** |
| * History of structure selections. |
| * |
| * @see StructureSelectHandler |
| */ |
| public class StructureSelectionHistory { |
| |
| |
| private final ISourceEditor sourceEditor; |
| |
| private final List<IRegion> history; |
| |
| private final ISelectionChangedListener selectionListener; |
| private int selectionChangeListenerCounter; |
| |
| private final CopyOnWriteIdentityListSet<IUpdate> updateActions= new CopyOnWriteIdentityListSet<>(); |
| |
| |
| public StructureSelectionHistory(final ISourceEditor editor) { |
| this.sourceEditor= editor; |
| this.history= new ArrayList<>(); |
| this.selectionListener= new ISelectionChangedListener() { |
| @Override |
| public void selectionChanged(final SelectionChangedEvent event) { |
| if (StructureSelectionHistory.this.selectionChangeListenerCounter == 0) { |
| flush(); |
| } |
| } |
| }; |
| this.sourceEditor.getViewer().getSelectionProvider().addSelectionChangedListener(this.selectionListener); |
| } |
| |
| |
| public void addUpdateListener(final IUpdate action) { |
| this.updateActions.add(action); |
| } |
| |
| private final void updateState() { |
| for (final IUpdate action : this.updateActions.toList()) { |
| action.update(); |
| } |
| } |
| |
| public boolean isEmpty() { |
| return this.history.isEmpty(); |
| } |
| |
| public void remember(final IRegion range) { |
| this.history.add(range); |
| updateState(); |
| } |
| |
| public IRegion getLast() { |
| if (isEmpty()) { |
| return null; |
| } |
| final IRegion result= this.history.remove(this.history.size() - 1); |
| updateState(); |
| return result; |
| } |
| |
| public void flush() { |
| if (this.history.isEmpty()) { |
| return; |
| } |
| this.history.clear(); |
| updateState(); |
| } |
| |
| public void ignoreSelectionChanges() { |
| this.selectionChangeListenerCounter++; |
| } |
| |
| public void listenToSelectionChanges() { |
| this.selectionChangeListenerCounter--; |
| } |
| |
| public void dispose() { |
| this.sourceEditor.getViewer().getSelectionProvider().removeSelectionChangedListener(this.selectionListener); |
| } |
| |
| } |