li.strolch.service.api

Class Command

java.lang.Object

li.strolch.service.api.Command

All Implemented Interfaces:

Restrictable

public abstract class Command
extends Object
implements Restrictable

Implementation of the Command Pattern to create re-usable components which are performed during StrolchTransactions as part of the execution of Services

Note: Do not call doCommand() from Services or other places. Add Command instances to a StrolchTransaction by calling StrolchTransaction.addCommand(Command)

Author:

Robert von Burg

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	logger

Constructor Summary

Constructors

Constructor and Description
Command(ComponentContainer container, StrolchTransaction tx) Instantiate a new Command

Method Summary

Modifier and Type	Method and Description
abstract void	doCommand() Clients implement this method to perform the work which is to be done in this Command.
protected <V> V	getComponent(Class<V> clazz) Allows the concrete Command implementation access to StrolchComponents at runtime
protected ComponentContainer	getContainer()
protected <T extends StrolchPolicy> T	getPolicy(Class<T> policyClass, PolicyContainer policyContainer) Returns a StrolchPolicy instance from the given parameters
String	getPrivilegeName()
Object	getPrivilegeValue()
protected void	runAs(String username, PrivilegedRunnable runnable) Performs the given PrivilegedRunnable as a system user with the given username
protected void	runAs(String username, SystemAction action) Performs the given SystemAction as a system user with the given username
protected void	runAsAgent(PrivilegedRunnable runnable) Performs the given PrivilegedRunnable as the privileged system user StrolchConstants.SYSTEM_USER_AGENT
protected void	runAsAgent(SystemAction action) Performs the given SystemAction as the privileged system user StrolchConstants.SYSTEM_USER_AGENT
protected <V> V	runAsAgentWithResult(PrivilegedRunnableWithResult<V> runnable) Performs the given PrivilegedRunnableWithResult as the privileged system user StrolchConstants.SYSTEM_USER_AGENT
protected <V> V	runAsAgentWithResult(SystemActionWithResult<V> action) Performs the given SystemAction as the privileged system user StrolchConstants.SYSTEM_USER_AGENT
protected <V> V	runWithResult(String username, PrivilegedRunnableWithResult<V> runnable) Performs the given PrivilegedRunnableWithResult as a system user with the given username
protected <T> T	runWithResult(String username, SystemActionWithResult<T> action) Performs the given SystemAction as a system user with the given username
protected StrolchTransaction	tx() Returns the StrolchTransaction bound to this Command's runtime
abstract void	undo() Should the transaction fail, either due to a Command throwing an exception when validate() is called, or while committing the transaction, then this method should properly undo any changes it has done.
abstract void	validate() To ensure that as few possibilities for exceptions as possible occur when doCommand() is called, the Command should verify any input data so that a doCommand() can be performed without exceptions

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final org.slf4j.Logger logger

Constructor Detail

Command

public Command(ComponentContainer container,
               StrolchTransaction tx)

Instantiate a new Command

Parameters:

container - the ComponentContainer to access components at runtime

tx -

Method Detail

getComponent

protected <V> V getComponent(Class<V> clazz)
                      throws IllegalArgumentException

Allows the concrete Command implementation access to StrolchComponents at runtime

Parameters:

clazz - the type of component to be returned

Returns:

the component with the given Class which is registered on the ComponentContainer

Throws:

IllegalArgumentException - if the component with the given class does not exist

getContainer

protected ComponentContainer getContainer()

Returns:

the container

getPolicy

protected <T extends StrolchPolicy> T getPolicy(Class<T> policyClass,
                                                PolicyContainer policyContainer)

Returns a StrolchPolicy instance from the given parameters

Parameters:

policyClass - the policy type to return. The simple name of the class determines the type of Policy to return.

policyDefs - the policy defs from which to get the policy by using the simple name of the policy class to determine the type of policy to return

Returns:

the policy

runAs

protected void runAs(String username,
                     SystemAction action)
              throws PrivilegeException

Performs the given SystemAction as a system user with the given username

Parameters:

username - the name of the system user to perform the action as

action - the action to perform

Throws:

PrivilegeException

runWithResult

protected <T> T runWithResult(String username,
                              SystemActionWithResult<T> action)
                       throws PrivilegeException

Performs the given SystemAction as a system user with the given username

Parameters:

username - the name of the system user to perform the action as

action - the action to perform

Returns:

the result

Throws:

PrivilegeException

runAs

protected void runAs(String username,
                     PrivilegedRunnable runnable)
              throws PrivilegeException

Performs the given PrivilegedRunnable as a system user with the given username

Parameters:

username - the name of the system user to perform the action as

runnable - the runnable to perform

Throws:

PrivilegeException

runWithResult

protected <V> V runWithResult(String username,
                              PrivilegedRunnableWithResult<V> runnable)
                       throws PrivilegeException

Performs the given PrivilegedRunnableWithResult as a system user with the given username

Parameters:

username - the name of the system user to perform the action as

runnable - the runnable to perform

Returns:

the result

Throws:

PrivilegeException

runAsAgent

protected void runAsAgent(SystemAction action)
                   throws PrivilegeException

Performs the given SystemAction as the privileged system user StrolchConstants.SYSTEM_USER_AGENT

Parameters:

username - the name of the system user to perform the action as

action - the action to perform

Throws:

PrivilegeException

runAsAgentWithResult

protected <V> V runAsAgentWithResult(SystemActionWithResult<V> action)
                              throws PrivilegeException

Performs the given SystemAction as the privileged system user StrolchConstants.SYSTEM_USER_AGENT

Parameters:

username - the name of the system user to perform the action as

action - the action to perform

Returns:

the result

Throws:

PrivilegeException

runAsAgent

protected void runAsAgent(PrivilegedRunnable runnable)
                   throws PrivilegeException

Performs the given PrivilegedRunnable as the privileged system user StrolchConstants.SYSTEM_USER_AGENT

Parameters:

action - the action to perform

Throws:

PrivilegeException

runAsAgentWithResult

protected <V> V runAsAgentWithResult(PrivilegedRunnableWithResult<V> runnable)
                              throws PrivilegeException

Performs the given PrivilegedRunnableWithResult as the privileged system user StrolchConstants.SYSTEM_USER_AGENT

Parameters:

action - the action to perform

Returns:

the result

Throws:

PrivilegeException

tx

protected StrolchTransaction tx()

Returns the StrolchTransaction bound to this Command's runtime

Returns:

the StrolchTransaction bound to this Command's runtime

getPrivilegeName

public String getPrivilegeName()

Specified by:

getPrivilegeName in interface Restrictable

See Also:

Restrictable.getPrivilegeName()

getPrivilegeValue

public Object getPrivilegeValue()

Specified by:

getPrivilegeValue in interface Restrictable

See Also:

Restrictable.getPrivilegeValue()

validate

public abstract void validate()

To ensure that as few possibilities for exceptions as possible occur when doCommand() is called, the Command should verify any input data so that a doCommand() can be performed without exceptions

doCommand

public abstract void doCommand()

Clients implement this method to perform the work which is to be done in this Command.

Note: Do not call this method directly, this method is called by the StrolchTransaction when the transaction is committed. Add this Command to the transaction by calling StrolchTransaction.addCommand(Command)

undo

public abstract void undo()

Should the transaction fail, either due to a Command throwing an exception when validate() is called, or while committing the transaction, then this method should properly undo any changes it has done. It is imperative that this method does not throw further exceptions and that the state to be rolled back is remembered in the Command during committing