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java.lang.Objectjavax.faces.application.StateManager
public abstract class StateManager
Responsible for storing sufficient information about a component tree so that an identical tree can later be recreated.
It is up to the concrete implementation to decide whether to use information from the "view template" that was used to first create the view, or whether to store sufficient information to enable the view to be restored without any reference to the original template. However as JSF components have mutable fields that can be set by code, and affected by user input, at least some state does need to be kept in order to recreate a previously-existing component tree.
There are two different options defined by the specification: "client" and "server" state.
When "client" state is configured, all state information required to create the tree is embedded within the data rendered to the client. Note that because data received from a remote client must always be treated as "tainted", care must be taken when using such data. Some StateManager implementations may use encryption to ensure that clients cannot modify the data, and that the data received on postback is therefore trustworthy.
When "server" state is configured, the data is saved somewhere "on the back end", and (at most) a token is embedded in the data rendered to the user.
This class is usually invoked by a concrete implementation of ViewHandler.
Note that class ViewHandler isolates JSF components from the details of the request format. This class isolates JSF components from the details of the response format. Because request and response are usually tightly coupled, the StateManager and ViewHandler implementations are also usually fairly tightly coupled (ie the ViewHandler/StateManager implementations come as pairs).
See also the JSF Specification
Nested Class Summary | |
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class |
StateManager.SerializedView
Deprecated. |
Field Summary | |
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static String |
STATE_SAVING_METHOD_CLIENT
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static String |
STATE_SAVING_METHOD_PARAM_NAME
Define the state method to be used. |
static String |
STATE_SAVING_METHOD_SERVER
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Constructor Summary | |
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StateManager()
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Method Summary | |
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protected Object |
getComponentStateToSave(FacesContext context)
Deprecated. |
protected Object |
getTreeStructureToSave(FacesContext context)
Deprecated. |
boolean |
isSavingStateInClient(FacesContext context)
|
protected void |
restoreComponentState(FacesContext context,
UIViewRoot viewRoot,
String renderKitId)
Deprecated. |
protected UIViewRoot |
restoreTreeStructure(FacesContext context,
String viewId,
String renderKitId)
Deprecated. |
abstract UIViewRoot |
restoreView(FacesContext context,
String viewId,
String renderKitId)
|
StateManager.SerializedView |
saveSerializedView(FacesContext context)
Deprecated. |
Object |
saveView(FacesContext context)
Returns an object that is sufficient to recreate the component tree that is the viewroot of the specified context. |
void |
writeState(FacesContext context,
Object state)
Associate the provided state object with the current response being generated. |
void |
writeState(FacesContext context,
StateManager.SerializedView state)
Deprecated. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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@JSFWebConfigParam(defaultValue="server", expectedValues="server,client", since="1.1") public static final String STATE_SAVING_METHOD_PARAM_NAME
When "client" state is configured, all state information required to create the tree is embedded within the data rendered to the client. Note that because data received from a remote client must always be treated as "tainted", care must be taken when using such data. Some StateManager implementations may use encryption to ensure that clients cannot modify the data, and that the data received on postback is therefore trustworthy.
When "server" state is configured, the data is saved somewhere "on the back end", and (at most) a token is embedded in the data rendered to the user.
public static final String STATE_SAVING_METHOD_CLIENT
public static final String STATE_SAVING_METHOD_SERVER
Constructor Detail |
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public StateManager()
Method Detail |
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public StateManager.SerializedView saveSerializedView(FacesContext context)
Deprecated; use saveView instead.
public Object saveView(FacesContext context)
The return value is suitable for passing to method writeState.
protected Object getTreeStructureToSave(FacesContext context)
Using this data, a tree of components which has the same "shape" as the original component tree can be recreated. However the component instances themselves will have only their default values, ie their member fields will not have been set to the original values.
Deprecated; use saveView instead.
protected Object getComponentStateToSave(FacesContext context)
Deprecated; use saveView instead.
public void writeState(FacesContext context, StateManager.SerializedView state) throws IOException
When client-side state is enabled, it is expected that method writes the data contained in the state parameter to the response somehow.
When server-side state is enabled, at most a "token" is expected to be written.
Deprecated; use writeState(FacesContext, Object) instead. This method was abstract in JSF1.1, but is now an empty non-abstract method so that old classes that implement this method continue to work, while new classes can just override the new writeState method rather than this one.
IOException
public void writeState(FacesContext context, Object state) throws IOException
When client-side state is enabled, it is expected that method writes the data contained in the state parameter to the response somehow.
When server-side state is enabled, at most a "token" is expected to be written.
This method should be overridden by subclasses. It is not abstract because a default implementation is provided that forwards to the old writeState method; this allows subclasses of StateManager written using the JSF1.1 API to continue to work.
IOException
public abstract UIViewRoot restoreView(FacesContext context, String viewId, String renderKitId)
protected UIViewRoot restoreTreeStructure(FacesContext context, String viewId, String renderKitId)
protected void restoreComponentState(FacesContext context, UIViewRoot viewRoot, String renderKitId)
public boolean isSavingStateInClient(FacesContext context)
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