burlap.oomdp.singleagent

Class ObjectParameterizedAction

java.lang.Object

burlap.oomdp.singleagent.Action

burlap.oomdp.singleagent.ObjectParameterizedAction

Direct Known Subclasses:

BlocksWorld.StackAction, BlocksWorld.UnstackAction

public abstract class ObjectParameterizedAction
extends Action

If your Action implementation is paramerterized to OO-MDP ObjectInstance references, you can subclass this Action subclass to easily provide that functionality. The GroundedAction instance associated with this action is ObjectParameterizedAction.ObjectParameterizedGroundedAction, which implements the AbstractObjectParameterizedGroundedAction, since its parameters refer to OO-MDP ObjectInstance references.

The string array in the ObjectParameterizedAction(String, burlap.oomdp.core.Domain, String[]) constructor specifies the valid type of ObjectClass to which the parameters must belong. For example, in BlocksWorld, we might define a "stack" ObjectParameterizedAction that takes two parameters that each must be instances of the BLOCK class. In such a case, the String array passed to the constructor of the stack ObjectParameterizedAction would be new String[]{"BLOCK", "BLOCK"}.

It may also be the case that the order of parameters for an ObjectParameterizedAction is unimportant. For example, a cooking domain might have a "combine" action that combines two INGREDIENT objects. In such a case, the effect of combine(ing1, ing2) would be the same as combine(ing2, ing1). Our action definition can include this parameter symmetry information by assigning parameters to the same parameter order group. The order of parameters in the same parameter order group and be swapped without affecting results, but the order of parameters in different groups cannot be swapped without affecting performance. By default the parameter order group of parameters are all assumed to be different, which means the order of the parameters is important. However, by using the ObjectParameterizedAction(String, burlap.oomdp.core.Domain, String[], String[]) method, each parameter can also be set to a parameter order group. For example, the parameterClasses of the combine action would be new String[]{INGREDIENT, INGREDIENT}, and the parameterOrderGroups would be new String[]{g1, g1}, thereby placing them in the same group to indicate that their order is unimportant. Specifying parameter order groups is useful because it allows the list of ObjectParameterizedAction.ObjectParameterizedGroundedAction instances returned by the getAllApplicableGroundedActions(burlap.oomdp.core.states.State) method to exclude multiple parameterizations that have the same effect.

Author:

James MacGlashan.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ObjectParameterizedAction.ObjectParameterizedGroundedAction

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String[]	parameterClasses The object classes each parameter of this action can accept; empty list for a parameter-less action (which is the default)
protected java.lang.String[]	parameterOrderGroup Specifies the parameter order group each parameter.

Fields inherited from class burlap.oomdp.singleagent.Action

actionObservers, domain, name

Constructor Summary

Constructors

Constructor and Description
ObjectParameterizedAction(java.lang.String name, Domain domain, java.lang.String[] parameterClasses) Initializes the action with the name of the action, the domain to which it belongs, and the parameters it takes.
ObjectParameterizedAction(java.lang.String name, Domain domain, java.lang.String[] parameterClasses, java.lang.String[] parameterOrderGroups) Initializes the action with the name of the action, the domain to which it belongs, the parameters it takes, and the parameter order groups.

Method Summary

Methods

Modifier and Type	Method and Description
java.util.List<GroundedAction>	getAllApplicableGroundedActions(State s) Returns all possible groundings of this action that can be applied in the provided State.
GroundedAction	getAssociatedGroundedAction() Returns a GroundedAction instance that points to this Action, but does not have any parameters--if any--set.
java.lang.String[]	getParameterClasses() Returns a String array of the names of of the object classes to which bound parameters must belong
java.lang.String[]	getParameterOrderGroups() Returns the a String array specifying the parameter order group of each parameter.
boolean	isParameterized() Returns true if this action is parameterized; false otherwise.
abstract boolean	parametersAreObjectIdentifierIndependent()

Methods inherited from class burlap.oomdp.singleagent.Action

addActionObserver, applicableInState, clearAllActionsObservers, deterministicTransition, equals, getAllApplicableGroundedActionsFromActionList, getDomain, getGroundedAction, getName, hashCode, isPrimitive, performAction, performActionHelper, performInEnvironment

Methods inherited from class java.lang.Object

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

Field Detail

parameterClasses

protected java.lang.String[] parameterClasses

The object classes each parameter of this action can accept; empty list for a parameter-less action (which is the default)

parameterOrderGroup

protected java.lang.String[] parameterOrderGroup

Specifies the parameter order group each parameter. Parameters in the same order group are order invariant; that is, if you swapped the parameter assignments for for parameters in the same group, the action would have the same effect. However, if you swapped the parameter assignments of two parameters in different order groups, the action would have a different effect.

Constructor Detail

ObjectParameterizedAction

public ObjectParameterizedAction(java.lang.String name,
                         Domain domain,
                         java.lang.String[] parameterClasses)

Initializes the action with the name of the action, the domain to which it belongs, and the parameters it takes. The action will also be automatically be added to the domain. The parameter order group is set to be a unique order group for each parameter.

Parameters:

name - the name of the action

domain - the domain to which the action belongs

parameterClasses - a String array of the names of the object classes to which bound parameters must belong

ObjectParameterizedAction

public ObjectParameterizedAction(java.lang.String name,
                         Domain domain,
                         java.lang.String[] parameterClasses,
                         java.lang.String[] parameterOrderGroups)

Initializes the action with the name of the action, the domain to which it belongs, the parameters it takes, and the parameter order groups. The action will also be automatically be added to the domain.

Parameters:

name - the name of the action

domain - the domain to which the action belongs

parameterClasses - a String array of the names of the object classes to which bound parameters must belong

parameterOrderGroups - the order group assignments for each of the parameters.

Method Detail

getParameterClasses

public final java.lang.String[] getParameterClasses()

Returns a String array of the names of of the object classes to which bound parameters must belong

Returns:

a String array of the names of of the object classes to which bound parameters must belong. The array is empty if this action does not require parameters.

getParameterOrderGroups

public final java.lang.String[] getParameterOrderGroups()

Returns the a String array specifying the parameter order group of each parameter.

Returns:

the a String array specifying the parameter order group of each parameter. The array is empty if this action does not require parameters.

parametersAreObjectIdentifierIndependent

public abstract boolean parametersAreObjectIdentifierIndependent()

isParameterized

public boolean isParameterized()

Description copied from class: Action

Returns true if this action is parameterized; false otherwise.

Specified by:

isParameterized in class Action

Returns:

true if this Action is parameterized; false if it is not.

getAssociatedGroundedAction

public GroundedAction getAssociatedGroundedAction()

Description copied from class: Action

Returns a GroundedAction instance that points to this Action, but does not have any parameters--if any--set.

Specified by:

getAssociatedGroundedAction in class Action

Returns:

a GroundedAction instance.

getAllApplicableGroundedActions

public java.util.List<GroundedAction> getAllApplicableGroundedActions(State s)

Description copied from class: Action

Returns all possible groundings of this action that can be applied in the provided State. To check if a grounded action is applicable in the state, the Action.applicableInState(State, burlap.oomdp.singleagent.GroundedAction) method is checked. The default behavior of this method is to treat the parameters as possible object bindings, finding all bindings that satisfy the object class typing specified and then checking them against the Action.applicableInState(State, burlap.oomdp.singleagent.GroundedAction) method. However, this class can also be overridden to provide custom grounding behavior or non-object based parametrization.

Specified by:

getAllApplicableGroundedActions in class Action

Parameters:

s - the State in which all applicable grounded actions of this Action object should be returned.

Returns:

a list of all applicable GroundedActions of this Action object in in the given State