/*
* This file is part of NucleusFramework for Bukkit, licensed under the MIT License (MIT).
*
* Copyright (c) JCThePants (www.jcwhatever.com)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.jcwhatever.nucleus.utils;
import com.jcwhatever.nucleus.managed.scheduler.Scheduler;
import com.jcwhatever.nucleus.mixins.IPluginOwned;
import com.jcwhatever.nucleus.utils.DependencyRunner.IDependantRunnable;
import com.jcwhatever.nucleus.managed.scheduler.IScheduledTask;
import com.jcwhatever.nucleus.managed.scheduler.TaskHandler;
import org.bukkit.plugin.Plugin;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Date;
import java.util.Deque;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
/**
* A utility class to execute code when a dependant condition is met within
* a timeout period.
*/
public class DependencyRunner<T extends IDependantRunnable> implements IPluginOwned {
private final Plugin _plugin;
private final Set<T> _runnables;
private final Deque<IFinishHandler<T>> _onFinished = new ArrayDeque<>(5);
private final Watcher _watcher = new Watcher();
private final int _timeoutSeconds;
private IScheduledTask _watcherTask;
private Date _endTime;
/**
* Specifies that status of dependencies.
*/
public enum DependencyStatus {
/**
* Dependencies are not ready.
*/
NOT_READY,
/**
* Required dependencies are ready but 1 or more
* optional dependencies are not.
*/
REQUIRED_READY,
/**
* All dependencies are ready.
*/
READY
}
/**
* Constructor.
*
* <p>Timeout is 20 seconds.</p>
*
* @param plugin The owning plugin.
*/
public DependencyRunner(Plugin plugin) {
this(plugin, 20);
}
/**
* Constructor.
*
* @param plugin The owning plugin.
* @param timeoutSeconds The timeout in seconds.
*/
public DependencyRunner(Plugin plugin, int timeoutSeconds) {
PreCon.notNull(plugin);
_plugin = plugin;
_runnables = new HashSet<>(20);
_timeoutSeconds = timeoutSeconds;
}
@Override
public Plugin getPlugin() {
return _plugin;
}
/**
* Get the number of seconds the {@link DependencyRunner} will run
* before timing out.
*/
public int getTimeoutSeconds() {
return _timeoutSeconds;
}
/**
* Add a dependant to run when its dependency conditions are met.
*
* @param runnable The dependant runnable to add.
*
* @return Self for chaining.
*/
public DependencyRunner add(T runnable) {
PreCon.notNull(runnable);
checkCanUse();
_runnables.add(runnable);
return this;
}
/**
* Add a collection of dependants to run when their dependency
* conditions are met.
*
* @param runnables The dependant runnables collection to add.
*
* @return Self for chaining.
*/
public DependencyRunner addAll(Collection<? extends T> runnables) {
PreCon.notNull(runnables);
checkCanUse();
_runnables.addAll(runnables);
return this;
}
/**
* Add an {@link IFinishHandler} to run when all dependant runnables have run
* or when the timeout is reached.
*
* @param onFinish The handler to add.
*
* @return Self for chaining.
*/
public DependencyRunner onFinish(IFinishHandler<T> onFinish) {
PreCon.notNull(onFinish);
checkCanUse();
_onFinished.add(onFinish);
return this;
}
/**
* Begin running dependant runnables when their dependency conditions are met
* until the timeout is reached.
*
* <p>Once this is called, the {@link DependencyRunner} cannot be used anymore.</p>
*/
public void start() {
checkCanUse();
_endTime = DateUtils.addSeconds(new Date(), _timeoutSeconds);
_watcherTask = Scheduler.runTaskRepeat(_plugin, 1, 10, _watcher);
}
// make sure start method has not been called.
private void checkCanUse() {
if (_watcherTask != null)
throw new RuntimeException("The DependencyRunner cannot be use after the load method is called.");
}
/**
* Interface for a dependant runnable.
*/
public interface IDependantRunnable extends Runnable {
/**
* Determine if the required dependency conditions have been met.
*/
DependencyStatus getDependencyStatus();
/**
* Run the code that has dependencies.
*/
@Override
void run();
}
/**
* Interface for a handler that is called when the {@link DependencyRunner} has
* finished running all of the dependant runnables or the timeout has been reached.
*
* @param <T> The {@link IDependantRunnable} type.
*/
public interface IFinishHandler<T extends IDependantRunnable> {
void onFinish(List<T> notRun);
}
/*
* Periodically checks dependencies and runs dependant runnables whose
* dependency conditions have been met. Cancels self when timeout is reached.
*/
private class Watcher extends TaskHandler {
@Override
public void run() {
Deque<T> runners = new ArrayDeque<>(_runnables);
while (!runners.isEmpty()) {
T runnable = runners.remove();
try {
DependencyStatus status = runnable.getDependencyStatus();
if (status == DependencyStatus.READY) {
runnable.run();
_runnables.remove(runnable);
}
}
catch (Exception e) {
e.printStackTrace();
}
}
if (_runnables.isEmpty() || new Date().compareTo(_endTime) >= 0)
cancelTask();
}
/*
* Invoked when the watcher is finished.
*/
@Override
protected void onCancel() {
// run if only optional dependencies are not ready
Deque<T> runners = new ArrayDeque<>(_runnables);
while (!runners.isEmpty()) {
T runnable = runners.remove();
try {
DependencyStatus status = runnable.getDependencyStatus();
if (status == DependencyStatus.READY ||
status == DependencyStatus.REQUIRED_READY) {
runnable.run();
_runnables.remove(runnable);
}
}
catch (Exception e) {
e.printStackTrace();
}
}
while (!_onFinished.isEmpty()) {
IFinishHandler<T> onFinished = _onFinished.remove();
onFinished.onFinish(new ArrayList<T>(_runnables));
}
}
}
}