Package jakarta.faces.application

Class StateManager

java.lang.Object

jakarta.faces.application.StateManager

Direct Known Subclasses:

StateManagerImpl, StateManagerWrapper

public abstract class StateManager
extends Object

StateManager directs the process of saving and restoring the view between requests. An implementation of this class must be thread-safe. The StateManager instance for an application is retrieved from the Application instance, and thus cannot know any details of the markup language created by the RenderKit being used to render a view. The StateManager utilizes a helper object (ResponseStateManager), that is provided by the RenderKit implementation and is therefore aware of the markup language details.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME	The runtime must interpret the value of this parameter as a comma separated list of view IDs, each of which must have their state saved using the state saving mechanism specified in Jakarta Faces 1.2.
static final String	IS_BUILDING_INITIAL_STATE	Marker within the FacesContext attributes map to indicate we are marking initial state, so the markInitialState() method of iterating components such as UIData could recognize this fact and save the initial state of descendents.
static final String	IS_SAVING_STATE	Marker within the FacesContext attributes map to indicate we are saving state.
static final String	PARTIAL_STATE_SAVING_PARAM_NAME	The ServletContext init parameter consulted by the runtime to determine if the partial state saving mechanism should be used.
static final String	SERIALIZE_SERVER_STATE_PARAM_NAME	If this param is set, and calling toLowerCase().equals("true") on a String representation of its value returns true, and the jakarta.faces.STATE_SAVING_METHOD is set to "server" (as indicated below), the server state must be guaranteed to be Serializable such that the aggregate state implements java.io.Serializable.
static final String	STATE_SAVING_METHOD_CLIENT	Constant value for the initialization parameter named by the STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on the client.
static final String	STATE_SAVING_METHOD_PARAM_NAME	The ServletContext init parameter consulted by the StateManager to tell where the state should be saved.
static final String	STATE_SAVING_METHOD_SERVER	Constant value for the initialization parameter named by the STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on the server.

Constructor Summary

Constructors

Constructor	Description
StateManager()

Method Summary

Modifier and Type	Method	Description
String	getViewState(FacesContext context)	Convenience method to return the view state as a String with no RenderKit specific markup.
boolean	isSavingStateInClient(FacesContext context)	Method to determine if the state is saved on the client.
void	writeState(FacesContext context, Object state)	Save the state represented in the specified state Object instance, in an implementation dependent manner.

Methods inherited from class java.lang.Object

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

Field Details

STATE_SAVING_METHOD_PARAM_NAME

public static final String STATE_SAVING_METHOD_PARAM_NAME

The ServletContext init parameter consulted by the StateManager to tell where the state should be saved. Valid values are given as the values of the constants: STATE_SAVING_METHOD_CLIENT or STATE_SAVING_METHOD_SERVER.

If this parameter is not specified, the default value is the value of the constant STATE_SAVING_METHOD_CLIENT.

See Also:

• Constant Field Values

PARTIAL_STATE_SAVING_PARAM_NAME

public static final String PARTIAL_STATE_SAVING_PARAM_NAME

The ServletContext init parameter consulted by the runtime to determine if the partial state saving mechanism should be used.

If undefined, the runtime must determine the version level of the application.

• For applications versioned at 1.2 and under, the runtime must not use the partial state saving mechanism.

• For applications versioned at 2.0 and above, the runtime must use the partial state saving mechanism.

If this parameter is defined, and the application is versioned at 1.2 and under, the runtime must not use the partial state saving mechanism. Otherwise, If this param is defined, and calling toLowerCase().equals("true") on a String representation of its value returns true, the runtime must use partial state mechanism. Otherwise the partial state saving mechanism must not be used.

Since:

2.0

See Also:

• Constant Field Values

FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME

public static final String FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME

The runtime must interpret the value of this parameter as a comma separated list of view IDs, each of which must have their state saved using the state saving mechanism specified in Jakarta Faces 1.2.

See Also:

• Constant Field Values

IS_SAVING_STATE

public static final String IS_SAVING_STATE

Marker within the FacesContext attributes map to indicate we are saving state. The implementation must set this marker into the map before starting the state saving traversal and the marker must be cleared, in a finally block, after the traversal is complete.

See Also:

• Constant Field Values

IS_BUILDING_INITIAL_STATE

public static final String IS_BUILDING_INITIAL_STATE

Marker within the FacesContext attributes map to indicate we are marking initial state, so the markInitialState() method of iterating components such as UIData could recognize this fact and save the initial state of descendents.

Since:

2.1

See Also:

• Constant Field Values

SERIALIZE_SERVER_STATE_PARAM_NAME

public static final String SERIALIZE_SERVER_STATE_PARAM_NAME

If this param is set, and calling toLowerCase().equals("true") on a String representation of its value returns true, and the jakarta.faces.STATE_SAVING_METHOD is set to "server" (as indicated below), the server state must be guaranteed to be Serializable such that the aggregate state implements java.io.Serializable. The intent of this parameter is to ensure that the act of writing out the state to an ObjectOutputStream would not throw a NotSerializableException, but the runtime is not required verify this before saving the state.

Since:

2.2

See Also:

• Constant Field Values

STATE_SAVING_METHOD_CLIENT

public static final String STATE_SAVING_METHOD_CLIENT

Constant value for the initialization parameter named by the STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on the client.

See Also:

• Constant Field Values

STATE_SAVING_METHOD_SERVER

public static final String STATE_SAVING_METHOD_SERVER

Constant value for the initialization parameter named by the STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on the server.

See Also:

• Constant Field Values

Constructor Details

StateManager

public StateManager()

Method Details

writeState

public void writeState(FacesContext context,
 Object state)
                throws IOException

Save the state represented in the specified state Object instance, in an implementation dependent manner.

This method will typically simply delegate the actual writing to the writeState() method of the ResponseStateManager instance provided by the RenderKit being used to render this view. This method assumes that the caller has positioned the ResponseWriter at the correct position for the saved state to be written.

Parameters:

context - FacesContext for the current request

state - the state to be written

Throws:

IOException - when an I/O error occurs.

Since:

1.2

isSavingStateInClient

public boolean isSavingStateInClient(FacesContext context)

Method to determine if the state is saved on the client.

Parameters:

context - the Faces context.

Returns:

true if and only if the value of the ServletContext init parameter named by the value of the constant STATE_SAVING_METHOD_PARAM_NAME is equal (ignoring case) to the value of the constant STATE_SAVING_METHOD_CLIENT. false otherwise.

Throws:

NullPointerException - if context is null.

getViewState

public String getViewState(FacesContext context)

Convenience method to return the view state as a String with no RenderKit specific markup. This default implementation of this method will call StateManagementStrategy.saveView(FacesContext) and passing the result to and returning the resulting value from ResponseStateManager.getViewState(jakarta.faces.context.FacesContext, Object).

Parameters:

context - FacesContext for the current request

Returns:

the view state.

Since:

2.0