| /* |
| * Copyright 2000-2011 JetBrains s.r.o. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.intellij.openapi.roots; |
| |
| import com.intellij.openapi.components.ServiceManager; |
| import com.intellij.openapi.project.Project; |
| import com.intellij.openapi.util.ModificationTracker; |
| |
| /** |
| * @author yole |
| */ |
| public abstract class ProjectRootModificationTracker implements ModificationTracker { |
| private static final ProjectRootModificationTracker NEVER_CHANGED = new ProjectRootModificationTracker() { |
| @Override |
| public long getModificationCount() { |
| return 0; |
| } |
| }; |
| |
| public static ProjectRootModificationTracker getInstance(Project project) { |
| ProjectRootModificationTracker instance = ServiceManager.getService(project, ProjectRootModificationTracker.class); |
| if (instance == null) return NEVER_CHANGED; |
| return instance; |
| } |
| } |