| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * 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 vogar.tasks; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.List; |
| import vogar.Console; |
| import vogar.Result; |
| |
| /** |
| * A task necessary to accomplish the user's requested actions. Tasks have |
| * prerequisites; a task must not be run until it reports that it is runnable. |
| * Tasks may be run at most once; running a task produces a result. |
| */ |
| public abstract class Task { |
| private final String name; |
| final List<Task> tasksThatMustFinishFirst = new ArrayList<Task>(); |
| final List<Task> tasksThatMustFinishSuccessfullyFirst = new ArrayList<Task>(); |
| volatile Result result; |
| Exception thrown; |
| |
| protected Task(String name) { |
| this.name = name; |
| } |
| |
| /** |
| * Returns true if this task is an action task. The queue imposes limits |
| * on how many actions may be run concurrently. |
| */ |
| public boolean isAction() { |
| return false; |
| } |
| |
| public Task after(Task prerequisite) { |
| tasksThatMustFinishFirst.add(prerequisite); |
| return this; |
| } |
| |
| public Task after(Collection<Task> prerequisites) { |
| tasksThatMustFinishFirst.addAll(prerequisites); |
| return this; |
| } |
| |
| public Task afterSuccess(Task prerequisite) { |
| tasksThatMustFinishSuccessfullyFirst.add(prerequisite); |
| return this; |
| } |
| |
| public Task afterSuccess(Collection<Task> prerequisitess) { |
| tasksThatMustFinishSuccessfullyFirst.addAll(prerequisitess); |
| return this; |
| } |
| |
| public final boolean isRunnable() { |
| for (Task task : tasksThatMustFinishFirst) { |
| if (task.result == null) { |
| return false; |
| } |
| } |
| for (Task task : tasksThatMustFinishSuccessfullyFirst) { |
| if (task.result != Result.SUCCESS) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| protected abstract Result execute() throws Exception; |
| |
| final void run(Console console) { |
| if (result != null) { |
| throw new IllegalStateException(); |
| } |
| try { |
| console.verbose("running " + this); |
| result = execute(); |
| } catch (Exception e) { |
| thrown = e; |
| result = Result.ERROR; |
| } |
| |
| if (result != Result.SUCCESS) { |
| console.verbose("warning " + this + " " + result); |
| } |
| } |
| |
| @Override public final String toString() { |
| return name; |
| } |
| } |