org.eclipse.jetty.util.component.AggregateLifeCycle Maven / Gradle / Ivy
//
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// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
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// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
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//
package org.eclipse.jetty.util.component;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/**
* An AggregateLifeCycle is an {@link LifeCycle} implementation for a collection of contained beans.
*
* Beans can be added the AggregateLifeCycle either as managed beans or as unmanaged beans. A managed bean is started, stopped and destroyed with the aggregate.
* An unmanaged bean is associated with the aggregate for the purposes of {@link #dump()}, but it's lifecycle must be managed externally.
*
* When a bean is added, if it is a {@link LifeCycle} and it is already started, then it is assumed to be an unmanaged bean.
* Otherwise the methods {@link #addBean(Object, boolean)}, {@link #manage(Object)} and {@link #unmanage(Object)} can be used to
* explicitly control the life cycle relationship.
*
* If adding a bean that is shared between multiple {@link AggregateLifeCycle} instances, then it should be started before being added, so it is unmanaged, or
* the API must be used to explicitly set it as unmanaged.
*
*/
public class AggregateLifeCycle extends AbstractLifeCycle implements Destroyable, Dumpable
{
private static final Logger LOG = Log.getLogger(AggregateLifeCycle.class);
private final List _beans=new CopyOnWriteArrayList();
private boolean _started=false;
private class Bean
{
Bean(Object b)
{
_bean=b;
}
final Object _bean;
volatile boolean _managed=true;
public String toString()
{
return "{"+_bean+","+_managed+"}";
}
}
/* ------------------------------------------------------------ */
/**
* Start the managed lifecycle beans in the order they were added.
* @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStart()
*/
@Override
protected void doStart() throws Exception
{
for (Bean b:_beans)
{
if (b._managed && b._bean instanceof LifeCycle)
{
LifeCycle l=(LifeCycle)b._bean;
if (!l.isRunning())
l.start();
}
}
// indicate that we are started, so that addBean will start other beans added.
_started=true;
super.doStart();
}
/* ------------------------------------------------------------ */
/**
* Stop the joined lifecycle beans in the reverse order they were added.
* @see org.eclipse.jetty.util.component.AbstractLifeCycle#doStart()
*/
@Override
protected void doStop() throws Exception
{
_started=false;
super.doStop();
List reverse = new ArrayList(_beans);
Collections.reverse(reverse);
for (Bean b:reverse)
{
if (b._managed && b._bean instanceof LifeCycle)
{
LifeCycle l=(LifeCycle)b._bean;
if (l.isRunning())
l.stop();
}
}
}
/* ------------------------------------------------------------ */
/**
* Destroy the joined Destroyable beans in the reverse order they were added.
* @see org.eclipse.jetty.util.component.Destroyable#destroy()
*/
public void destroy()
{
List reverse = new ArrayList(_beans);
Collections.reverse(reverse);
for (Bean b:reverse)
{
if (b._bean instanceof Destroyable && b._managed)
{
Destroyable d=(Destroyable)b._bean;
d.destroy();
}
}
_beans.clear();
}
/* ------------------------------------------------------------ */
/** Is the bean contained in the aggregate.
* @param bean
* @return True if the aggregate contains the bean
*/
public boolean contains(Object bean)
{
for (Bean b:_beans)
if (b._bean==bean)
return true;
return false;
}
/* ------------------------------------------------------------ */
/** Is the bean joined to the aggregate.
* @param bean
* @return True if the aggregate contains the bean and it is joined
*/
public boolean isManaged(Object bean)
{
for (Bean b:_beans)
if (b._bean==bean)
return b._managed;
return false;
}
/* ------------------------------------------------------------ */
/**
* Add an associated bean.
* If the bean is a {@link LifeCycle}, then it will be managed if it is not
* already started and umanaged if it is already started. The {@link #addBean(Object, boolean)}
* method should be used if this is not correct, or the {@link #manage(Object)} and {@link #unmanage(Object)}
* methods may be used after an add to change the status.
* @param o the bean object to add
* @return true if the bean was added or false if it has already been added.
*/
public boolean addBean(Object o)
{
// beans are joined unless they are started lifecycles
return addBean(o,!((o instanceof LifeCycle)&&((LifeCycle)o).isStarted()));
}
/* ------------------------------------------------------------ */
/** Add an associated lifecycle.
* @param o The lifecycle to add
* @param managed True if the LifeCycle is to be joined, otherwise it will be disjoint.
* @return true if bean was added, false if already present.
*/
public boolean addBean(Object o, boolean managed)
{
if (contains(o))
return false;
Bean b = new Bean(o);
b._managed=managed;
_beans.add(b);
if (o instanceof LifeCycle)
{
LifeCycle l=(LifeCycle)o;
// Start the bean if we are started
if (managed && _started)
{
try
{
l.start();
}
catch(Exception e)
{
throw new RuntimeException (e);
}
}
}
return true;
}
/* ------------------------------------------------------------ */
/**
* Manage a bean by this aggregate, so that it is started/stopped/destroyed with the
* aggregate lifecycle.
* @param bean The bean to manage (must already have been added).
*/
public void manage(Object bean)
{
for (Bean b :_beans)
{
if (b._bean==bean)
{
b._managed=true;
return;
}
}
throw new IllegalArgumentException();
}
/* ------------------------------------------------------------ */
/**
* Unmanage a bean by this aggregate, so that it is not started/stopped/destroyed with the
* aggregate lifecycle.
* @param bean The bean to manage (must already have been added).
*/
public void unmanage(Object bean)
{
for (Bean b :_beans)
{
if (b._bean==bean)
{
b._managed=false;
return;
}
}
throw new IllegalArgumentException();
}
/* ------------------------------------------------------------ */
/** Get dependent beans
* @return List of beans.
*/
public Collection