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.
* <p>
* 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.
* <p>
* 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.
* <p>
* 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.
* <p>
*/
public class AggregateLifeCycle extends AbstractLifeCycle implements Destroyable, Dumpable
{
private static final Logger LOG = Log.getLogger(AggregateLifeCycle.class);
private final List<Bean> _beans=new CopyOnWriteArrayList<Bean>();
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<Bean> reverse = new ArrayList<Bean>(_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<Bean> reverse = new ArrayList<Bean>(_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<Object> getBeans()
{
return getBeans(Object.class);
}
/* ------------------------------------------------------------ */
/** Get dependent beans of a specific class
* @see #addBean(Object)
* @param clazz
* @return List of beans.
*/
public <T> List<T> getBeans(Class<T> clazz)
{
ArrayList<T> beans = new ArrayList<T>();
for (Bean b:_beans)
{
if (clazz.isInstance(b._bean))
beans.add((T)(b._bean));
}
return beans;
}
/* ------------------------------------------------------------ */
/** Get dependent beans of a specific class.
* If more than one bean of the type exist, the first is returned.
* @see #addBean(Object)
* @param clazz
* @return bean or null
*/
public <T> T getBean(Class<T> clazz)
{
for (Bean b:_beans)
{
if (clazz.isInstance(b._bean))
return (T)b._bean;
}
return null;
}
/* ------------------------------------------------------------ */
/**
* Remove all associated bean.
*/
public void removeBeans ()
{
_beans.clear();
}
/* ------------------------------------------------------------ */
/**
* Remove an associated bean.
*/
public boolean removeBean (Object o)
{
Iterator<Bean> i = _beans.iterator();
while(i.hasNext())
{
Bean b=i.next();
if (b._bean==o)
{
_beans.remove(b);
return true;
}
}
return false;
}
/* ------------------------------------------------------------ */
public void dumpStdErr()
{
try
{
dump(System.err,"");
}
catch (IOException e)
{
LOG.warn(e);
}
}
/* ------------------------------------------------------------ */
public String dump()
{
return dump(this);
}
/* ------------------------------------------------------------ */
public static String dump(Dumpable dumpable)
{
StringBuilder b = new StringBuilder();
try
{
dumpable.dump(b,"");
}
catch (IOException e)
{
LOG.warn(e);
}
return b.toString();
}
/* ------------------------------------------------------------ */
public void dump(Appendable out) throws IOException
{
dump(out,"");
}
/* ------------------------------------------------------------ */
protected void dumpThis(Appendable out) throws IOException
{
out.append(String.valueOf(this)).append(" - ").append(getState()).append("\n");
}
/* ------------------------------------------------------------ */
public static void dumpObject(Appendable out,Object o) throws IOException
{
if (o instanceof LifeCycle)
out.append(String.valueOf(o)).append(" - ").append((AbstractLifeCycle.getState((LifeCycle)o))).append("\n");
else
out.append(String.valueOf(o)).append("\n");
}
/* ------------------------------------------------------------ */
public void dump(Appendable out,String indent) throws IOException
{
dumpThis(out);
int size=_beans.size();
if (size==0)
return;
int i=0;
for (Bean b : _beans)
{
i++;
if (b._managed)
{
out.append(indent).append(" +- ");
if (b._bean instanceof Dumpable)
((Dumpable)b._bean).dump(out,indent+(i==size?" ":" | "));
else
dumpObject(out,b._bean);
}
else
dumpObject(out,b._bean);
}
if (i!=size)
out.append(indent).append(" |\n");
}
/* ------------------------------------------------------------ */
public static void dump(Appendable out,String indent,Collection<?>... collections) throws IOException
{
if (collections.length==0)
return;
int size=0;
for (Collection<?> c : collections)
size+=c.size();
if (size==0)
return;
int i=0;
for (Collection<?> c : collections)
{
for (Object o : c)
{
i++;
out.append(indent).append(" +- ");
if (o instanceof Dumpable)
((Dumpable)o).dump(out,indent+(i==size?" ":" | "));
else
dumpObject(out,o);
}
if (i!=size)
out.append(indent).append(" |\n");
}
}
}