burlap.mdp.core.state

Class NullState

java.lang.Object

burlap.mdp.core.state.NullState

All Implemented Interfaces:

State

public final class NullState
extends java.lang.Object
implements State

A null state that contains no information. Access it via the singleton instance field.

Field Summary

Fields

Modifier and Type	Field and Description
static NullState	instance

Method Summary

Modifier and Type	Method and Description
State	copy() Returns a copy of this state suitable for creating state transitions.
boolean	equals(java.lang.Object obj)
java.lang.Object	get(java.lang.Object variableKey) Returns the value for the given variable key.
int	hashCode()
java.lang.String	toString()
java.util.List<java.lang.Object>	variableKeys() Returns the list of state variable keys.

Methods inherited from class java.lang.Object

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

Field Detail

instance

public static final NullState instance

Method Detail

variableKeys

public java.util.List<java.lang.Object> variableKeys()

Description copied from interface: State

Returns the list of state variable keys.

Specified by:

variableKeys in interface State

Returns:

the list of state variable keys.

get

public java.lang.Object get(java.lang.Object variableKey)

Description copied from interface: State

Returns the value for the given variable key. Changes to the returned value are not guaranteed to modify the state.

Specified by:

get in interface State

Parameters:

variableKey - the variable key

Returns:

the value for the given variable key

copy

public State copy()

Description copied from interface: State

Returns a copy of this state suitable for creating state transitions. This copy may be a shallow copy or deep copy and is domain specific. The State implementation may indicate its copy level with the DeepCopyState or ShallowCopyState annotations. If it is a shallow copy, you should not *directly* modify any fields of a copied state without copying the fields first, or it could contaminate the state from which the copy was made. Alternatively, use the MutableState.set(Object, Object) method to modify ShallowCopyState copied states, which for ShallowCopyState instances should perform a safe copy-on-write operation.

Specified by:

copy in interface State

Returns:

a copy of this state.

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object