Class w3c.jigsaw.http.ClientPool
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Class w3c.jigsaw.http.ClientPool

java.lang.Object
   |
   +----w3c.jigsaw.http.ClientPool

public class ClientPool
extends Object
implements PropertyMonitoring
The client pool is a kind of client factory. Each time the server gets a new connection, it calls the client pool to bound a client object (newly created or spared) to handle it.

Variable Index

 o MAX_CLIENT_P
The name of the property giving the maximum number of allowed clients.
 o MIN_CLIENT_P
The name of the property giving the number of clients to keep.

Method Index

 o addClient(boolean)
Create a new client for this pool.
 o cleanLRU()
 o clientConnectionFinished(Client)
Notify that this client has finished with its connection.
 o clientFinished(Client)
Notify that this client has been killed.
 o handleConnection(Socket)
Handle the given connection.
 o killClients(boolean)
 o killSomeClients()
Kill some client.
 o notifyIdle(Client)
The client notifies the pool that it enters idle state.
 o notifyUse(Client)
The client notifies the pool that is has been activated.
 o propertyChanged(String)
Some property have changed, update our setting.
 o resizeClientArray(int)
Resize our client array to the given number.
 o setMaxConnection()
 o shutdown(boolean)
Shutdown the client pool.

Variables

 o MAX_CLIENT_P
  public final static String MAX_CLIENT_P
The name of the property giving the maximum number of allowed clients. This property gives the maximum number of simultaneous connections to the server. When this number is exceeded, any incomming connection will be rejected.
 o MIN_CLIENT_P
  public final static String MIN_CLIENT_P
The name of the property giving the number of clients to keep. The ClientPool object keep alive this number of clients, ready to handle connections.

Methods

 o resizeClientArray
  protected synchronized void resizeClientArray(int newmax)
Resize our client array to the given number.
Parameters:
newmax - The new maximum size.
 o addClient
  protected synchronized ClientState addClient(boolean locked)
Create a new client for this pool.
Parameters:
locked - Mark this client as buzy.
 o setMaxConnection
  protected void setMaxConnection()
 o killSomeClients
  protected synchronized void killSomeClients()
Kill some client. Our buzy watermark exceeds the config given min spare client. Pick clients in LRU and kill them until the buzy count reaches the water mark again.
 o clientConnectionFinished
  protected synchronized void clientConnectionFinished(Client client)
Notify that this client has finished with its connection. If the pool wants the client to be freed (because it has too many of them), it makes the client kill itself (which will trigger a call to the clientFinished method, were enventual cleanup is performed).
Parameters:
client - The client that is done with its connection.
 o clientFinished
  protected synchronized void clientFinished(Client client)
Notify that this client has been killed.
Parameters:
client - The client that has terminate.
 o notifyUse
  protected void notifyUse(Client client)
The client notifies the pool that is has been activated. The client state object is updated to unmark the client as idle.

This method needs not be synchronized, as it affect only the client state, not the client list.

Parameters:
client - The activated client.
 o notifyIdle
  protected void notifyIdle(Client client)
The client notifies the pool that it enters idle state.

This method needs not be synchronized, as it affect only the client state, not the client list.

Parameters:
client - The client that is going to be idle.
 o propertyChanged
  public boolean propertyChanged(String name)
Some property have changed, update our setting.
Parameters:
name - The name of the property that has changed.
Returns:
A boolean, true if we updated ourself successfully.
 o handleConnection
  public synchronized void handleConnection(Socket socket)
Handle the given connection. Find a free client, bind it to the given socket, and run it. If we have reached our maximum allowed number of clients, kill some connections.

A client enters the LRU list (and become a candidate for kill) only after it has handle one request (or if some timeout expires). This is performed by the first call to notifyUse which will silently insert the client into the LRU if it was not there already.

This client pool does a lot of nice thinigs, but could probably be implemented in a much better way (while keeping the features it has). Contention arond the pool is probably concern number 1 of performances.

Parameters:
socket - The connection to handle.
 o killClients
  protected synchronized void killClients(boolean force)
 o cleanLRU
  protected synchronized void cleanLRU()
 o shutdown
  public void shutdown(boolean force)
Shutdown the client pool. If force is true, kill all running clients right now, otherwise, wait for them to terminate gracefully, and return when done.
Parameters:
force - Should we interrupt running clients.

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