org.apache.directory.server.protocol.shared.chain.impl
Class ChainBase

java.lang.Object
  org.apache.directory.server.protocol.shared.chain.impl.ChainBase

All Implemented Interfaces:

Chain, Command

public class ChainBase
extends java.lang.Object
implements Chain

Convenience base class for Chain implementations.

Version:

$Revision: 434432 $ $Date: 2006-08-24 12:52:26 -0400 (Thu, 24 Aug 2006) $

Author:

Apache Directory Project

Field Summary

protected Command[]	commands The list of Commands configured for this Chain, in the order in which they may delegate processing to the remainder of the Chain.
protected boolean	frozen Flag indicating whether the configuration of our commands list has been frozen by a call to the execute() method.

Constructor Summary

ChainBase()
Construct a Chain with no configured Commands.

ChainBase(java.util.Collection commands)
Construct a Chain configured with the specified Commands.

ChainBase(Command command)
Construct a Chain configured with the specified Command.

ChainBase(Command[] commands)
Construct a Chain configured with the specified Commands.

Method Summary

void	addCommand(Command command) Add a Command to the list of Commands that will be called in turn when this Chain's execute() method is called.
boolean	execute(Context context) Execute the processing represented by this Chain according to the following algorithm.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

commands

protected Command[] commands

The list of Commands configured for this Chain, in the order in which they may delegate processing to the remainder of the Chain.

frozen

protected boolean frozen

Flag indicating whether the configuration of our commands list has been frozen by a call to the execute() method.

Constructor Detail

ChainBase

public ChainBase()

Construct a Chain with no configured Commands.

ChainBase

public ChainBase(Command command)

Construct a Chain configured with the specified Command.

Parameters:

command - The Command to be configured

Throws:

java.lang.IllegalArgumentException - if command is null

ChainBase

public ChainBase(Command[] commands)

Construct a Chain configured with the specified Commands.

Parameters:

commands - The Commands to be configured

Throws:

java.lang.IllegalArgumentException - if commands, or one of the individual Command elements, is null

ChainBase

public ChainBase(java.util.Collection commands)

Construct a Chain configured with the specified Commands.

Parameters:

commands - The Commands to be configured

Throws:

java.lang.IllegalArgumentException - if commands, or one of the individual Command elements, is null

Method Detail

addCommand

public void addCommand(Command command)

Description copied from interface: Chain

Add a Command to the list of Commands that will be called in turn when this Chain's execute() method is called. Once execute() has been called at least once, it is no longer possible to add additional Commands; instead, an exception will be thrown.

Specified by:

addCommand in interface Chain

Parameters:

command - The Command to be added

execute

public boolean execute(Context context)
                throws java.lang.Exception

Description copied from interface: Chain

Execute the processing represented by this Chain according to the following algorithm.

• If there are no configured Commands in the Chain, return false.
• Call the execute() method of each Command configured on this chain, in the order they were added via calls to the addCommand() method, until the end of the configured Commands is encountered, or until one of the executed Commands returns true or throws an exception.
• Walk backwards through the Commands whose execute() methods, starting with the last one that was executed. If this Command instance is also a Filter, call its postprocess() method, discarding any exception that is thrown.
• If the last Command whose execute() method was called threw an exception, rethrow that exception.
• Otherwise, return the value returned by the execute() method of the last Command that was executed. This will be true if the last Command indicated that processing of this Context has been completed, or false if none of the called Commands returned true.

Specified by:

execute in interface Chain

Specified by:

execute in interface Command

Parameters:

context - The Context to be processed by this Chain

Returns:

true if the processing of this Context has been completed, or false if the processing of this Context should be delegated to a subsequent Command in an enclosing Chain

Throws:

java.lang.Exception - if thrown by one of the Commands in this Chain but not handled by a postprocess() method of a Filter

java.lang.IllegalArgumentException - if context is null