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/*******************************************************************************
* Copyright (c) 2018, TechEmpower, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name TechEmpower, Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL TECHEMPOWER, INC. BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*******************************************************************************/
package com.techempower;
import java.util.*;
import com.techempower.asynchronous.*;
import com.techempower.helper.*;
import com.techempower.log.*;
import com.techempower.scheduler.*;
import com.techempower.util.*;
/**
* A base for applications' main classes. Typically, an application that uses
* this framework will subclass either TechEmpowerApplication (for console
* applications) or GeminiApplication (for web applications). The resulting
* subclasses act as a central hub of references to application modules, such
* as the log, scheduler, request dispatcher, templater, and so on.
*/
public class TechEmpowerApplication
{
//
// Member variables.
//
private final Version version;
private final Log rootLog;
private final ComponentLog log;
private final Scheduler scheduler;
private final List asynchronousRscs;
private final List deferredRscs;
private final LogWriterManager logManager;
//
// Member methods.
//
/**
* Constructor. Overload to provide custom references.
*/
public TechEmpowerApplication()
{
// Create a Collection for the asynchronous resources.
this.asynchronousRscs = new ArrayList<>();
this.deferredRscs = new ArrayList<>();
this.version = constructVersion();
this.logManager = constructLogCloser();
// LogWriterManager is a special case that is started as soon as
// constructed.
this.logManager.begin();
this.rootLog = constructLog();
this.log = getLog("teap");
this.scheduler = constructScheduler();
}
/**
* Constructs a Version reference. Overload to return a custom object.
*/
protected Version constructVersion()
{
return new Version();
}
/**
* Constructs a Log reference. Overload to return a custom object.
*/
protected Log constructLog()
{
return new BasicLog(this);
}
/**
* Construct a Scheduler. Schedule events at construction time by
* overloading this method.
*/
protected Scheduler constructScheduler()
{
return new Scheduler(this);
}
/**
* Construct a LogWriterCloser.
*/
protected LogWriterManager constructLogCloser()
{
return new LogWriterManager(this);
}
/**
* Gets a Version object for this application. The Version holds items
* such as the name and version number of the application.
*/
public Version getVersion()
{
return version;
}
/**
* Gets a ComponentLog for a component.
*/
public ComponentLog getLog(String componentCode)
{
return rootLog.getComponentLog(componentCode);
}
/**
* Gets the application's ComponentLog.
*/
protected ComponentLog getComponentLog()
{
return log;
}
/**
* Gets the actual application log reference.
*/
public Log getApplicationLog()
{
return rootLog;
}
/**
* Gets the main application scheduler. If none exists it will be created.
* If no scheduler is desired for the application, do not call this method.
*/
public Scheduler getScheduler()
{
return scheduler;
}
/**
* Gets the application's LogWriterCloser.
*/
public LogWriterManager getLogManager()
{
return logManager;
}
/**
* Adds a DeferredStartAsynchronous resource for this application to
* manage. When the application is started or stopped, the resource will
* be started and stopped as well. Deferred resources are started
* approximately 2 seconds after the application starts and will not
* block the start of the application.
*/
public void addAsynchronous(DeferredStartAsynchronous async)
{
// Only add if we don't already have it in the list.
if (!deferredRscs.contains(async))
{
deferredRscs.add(async);
}
}
/**
* Adds an Asynchronous resource for this application to manage. When the
* application is started or stopped, the resource will be started and
* stopped as well.
*
* When designing an Asynchronous resource, keep in mind that the
* application's start-up will be blocked until the call to all resources'
* Asynchronous.begin() methods return.
*/
public void addAsynchronous(Asynchronous async)
{
// Only add if we don't already have it in the list.
if (!asynchronousRscs.contains(async))
{
asynchronousRscs.add(async);
}
}
/**
* Removes an Asynchronous resource.
*/
public void removeAsynchronous(Asynchronous async)
{
asynchronousRscs.remove(async);
}
/**
* Starts the Asynchronous resources.
*/
public void startAsynchronousResources()
{
// Start the async resources in the collection.
for (Asynchronous async : asynchronousRscs)
{
// Begin within this thread.
async.begin();
}
// Start a deferred asynchronous resources on separate threads.
if (!deferredRscs.isEmpty())
{
final DeferredAsynchronousStarter thread =
new DeferredAsynchronousStarter(deferredRscs);
thread.start();
}
}
/**
* Thread that runs the deferred Asynchronous resources.
*/
static final class DeferredAsynchronousStarter
extends Thread
{
private final List deferred;
private DeferredAsynchronousStarter(List deferred)
{
super("Deferred Asynchronous Object Starter");
this.deferred = deferred;
}
@Override
public void run()
{
// Sleep for 2 seconds.
ThreadHelper.sleep(2 * UtilityConstants.SECOND);
// Start the asynchronous resources.
for (Asynchronous async : deferred)
{
async.begin();
}
}
}
/**
* Stops the Asynchronous resources.
*/
public void stopAsynchronousResources()
{
// Stop the asynchronous resources.
for (Asynchronous async : asynchronousRscs)
{
async.end();
}
// Stop the deferred asynchronous resources.
for (DeferredStartAsynchronous async : deferredRscs)
{
async.end();
}
// The LogManager is a special case that we should stop after all other
// Asynchronous resources so that any log messages those write as they
// are stopping will be captured to the log.
logManager.end();
}
} // End TechEmpowerApplication.