org.openanzo.commands
Class CommandChain

java.lang.Object
  org.openanzo.commands.CommandChain

All Implemented Interfaces:

Command

public class CommandChain
extends java.lang.Object
implements Command

An CommandChain is an Command that is made up of a chain of Commands that get executed in order. The output of each command is placed in the input properties of the next command to reference if needed.

Author:

Matthew Roy ( mroy@cambridgesemantics.com ), Lee Feigenbaum ( feigenbl@us.ibm.com)

Constructor Summary

CommandChain()

Method Summary

void	addCommand(Command command) Add a command to the end of this command chain
void	addPrecondition(IPrecondition precondition) Add a precondition to this command that will get evaluated on the server to decide if the command can get commited.
java.lang.Object	execute() Method that is executed by local transaction manager when this command is processed.
java.lang.String	getCommandType() Returns a string representing the command type encompassed by this command.
IDataset	getDataset() Get the Dataset used by this command.
java.util.Set<IPrecondition>	getPreconditions() Return the set of preconditions for this command.
void	linkCommand(Command targetCommand, java.lang.String propertyName, Command sourceCommand) Linking commands allows for linking the output of one command to the input of another command.
void	setDataset(IDataset dataset) Set the Dataset used by this command, for example to create new resources.
void	setInputProperty(java.lang.String name, java.lang.Object value) An input property is a name/value pair that can be used by the command during its execution.
void	setPreconditions(java.util.Set<IPrecondition> preconditions) Set this commands preconditions to the given set.
void	setTransactionQueueHandler(ITransactionQueueManager transactionQueueHandler) Set the transactionQueueHandler on which this command is to execute

Methods inherited from class java.lang.Object

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

Constructor Detail

CommandChain

public CommandChain()

Method Detail

addCommand

public void addCommand(Command command)

Add a command to the end of this command chain

Parameters:

command - Command to add to end of chain.

linkCommand

public void linkCommand(Command targetCommand,
                        java.lang.String propertyName,
                        Command sourceCommand)
                 throws AnzoException

Linking commands allows for linking the output of one command to the input of another command.

Parameters:

targetCommand - Command on which input property is being set

propertyName - Name of the property under which to store the output of the source command

sourceCommand - Command whose output is used as input to the target command's input properties

Throws:

AnzoException - if the source command is not a member of this chain

execute

public java.lang.Object execute()

Description copied from interface: Command

Method that is executed by local transaction manager when this command is processed. Commands can return whatever object they choose, including null.

Specified by:

execute in interface Command

Returns:

results of running command

getDataset

public IDataset getDataset()

Description copied from interface: Command

Get the Dataset used by this command.

Specified by:

getDataset in interface Command

Returns:

the Dataset used by this command

setDataset

public void setDataset(IDataset dataset)

Description copied from interface: Command

Set the Dataset used by this command, for example to create new resources.

Specified by:

setDataset in interface Command

Parameters:

dataset - the dataset where statements are added or removed

getCommandType

public java.lang.String getCommandType()

Description copied from interface: Command

Returns a string representing the command type encompassed by this command.

Specified by:

getCommandType in interface Command

Returns:

CommandType for this Command

setInputProperty

public void setInputProperty(java.lang.String name,
                             java.lang.Object value)

Description copied from interface: Command

An input property is a name/value pair that can be used by the command during its execution.

Specified by:

setInputProperty in interface Command

Parameters:

name - Name of input property

value - Value of input property

addPrecondition

public void addPrecondition(IPrecondition precondition)

Description copied from interface: Command

Add a precondition to this command that will get evaluated on the server to decide if the command can get commited.

Specified by:

addPrecondition in interface Command

Parameters:

precondition - Precondition that is evaluated on the server

getPreconditions

public java.util.Set<IPrecondition> getPreconditions()

Description copied from interface: Command

Return the set of preconditions for this command.

Specified by:

getPreconditions in interface Command

Returns:

Set of preconditions

setPreconditions

public void setPreconditions(java.util.Set<IPrecondition> preconditions)

Description copied from interface: Command

Set this commands preconditions to the given set.

Specified by:

setPreconditions in interface Command

Parameters:

preconditions - Set of preconditions that are evaluated on the server

setTransactionQueueHandler

public void setTransactionQueueHandler(ITransactionQueueManager transactionQueueHandler)

Set the transactionQueueHandler on which this command is to execute

Parameters:

transactionQueueHandler - the transactionQueueHandler on which this command is to execute