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/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v. 2.0, which is available at
* http://www.eclipse.org/legal/epl-2.0.
*
* This Source Code may also be made available under the following Secondary
* Licenses when the conditions for such availability set forth in the
* Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
* version 2 with the GNU Classpath Exception, which is available at
* https://www.gnu.org/software/classpath/license.html.
*
* SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
*/
package javax.faces.application;
import static java.lang.Boolean.TRUE;
import java.io.IOException;
import javax.faces.component.NamingContainer;
import javax.faces.component.UIViewRoot;
import javax.faces.context.FacesContext;
import javax.faces.context.ResponseWriter;
import javax.faces.render.RenderKit;
import javax.faces.render.ResponseStateManager;
/**
*
* StateManager directs the process of saving and restoring the view
* between requests. An implementation of this class must be
* thread-safe. The {@link StateManager} instance for an application is retrieved from the
* {@link Application} instance, and thus cannot know any details of the markup language created by
* the {@link RenderKit} being used to render a view.
*
* The {@link StateManager} utilizes a helper
* object ({@link ResponseStateManager}), that is provided by the {@link RenderKit} implementation
* and is therefore aware of the markup language details.
*
*/
public abstract class StateManager {
// ------------------------------------------------------ Manifest Constants
/**
*
* 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:
* {@link #STATE_SAVING_METHOD_CLIENT} or {@link #STATE_SAVING_METHOD_SERVER}.
*
*
*
* If this parameter is not specified, the default value is the value of the constant
* {@link #STATE_SAVING_METHOD_CLIENT}.
*
*/
public static final String STATE_SAVING_METHOD_PARAM_NAME = "javax.faces.STATE_SAVING_METHOD";
/**
*
* 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
*/
public static final String PARTIAL_STATE_SAVING_PARAM_NAME = "javax.faces.PARTIAL_STATE_SAVING";
/**
*
* 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 Server Faces
* 1.2.
*
*/
public static final String FULL_STATE_SAVING_VIEW_IDS_PARAM_NAME = "javax.faces.FULL_STATE_SAVING_VIEW_IDS";
/**
*
* 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.
*
*/
public static final String IS_SAVING_STATE = "javax.faces.IS_SAVING_STATE";
/**
*
* Marker within the FacesContext attributes map to indicate we are marking initial
* state, so the markInitialState() method of iterating components such as
* {@link javax.faces.component.UIData} could recognize this fact and save the initial state of
* descendents.
*
*
* @since 2.1
*
*/
public final static String IS_BUILDING_INITIAL_STATE = "javax.faces.IS_BUILDING_INITIAL_STATE";
/**
*
* If this param is set, and calling toLowerCase().equals("true") on a String representation of
* its value returns true, and the javax.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
*/
public static final String SERIALIZE_SERVER_STATE_PARAM_NAME = "javax.faces.SERIALIZE_SERVER_STATE";
/**
*
* Constant value for the initialization parameter named by the
* STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on
* the client.
*
*/
public static final String STATE_SAVING_METHOD_CLIENT = "client";
/**
*
* Constant value for the initialization parameter named by the
* STATE_SAVING_METHOD_PARAM_NAME that indicates state saving should take place on
* the server.
*
*/
public static final String STATE_SAVING_METHOD_SERVER = "server";
private static final String IS_CALLED_FROM_API_CLASS = "javax.faces.ensureOverriddenInvocation";
private Boolean savingStateInClient;
// ---------------------------------------------------- State Saving Methods
/**
*
* Return the tree structure and component state information for the view contained in the
* specified {@link FacesContext} instance as an object of type
* StateManager.SerializedView. If there is no state information to be saved,
* return null instead.
*
*
*
* Components may opt out of being included in the serialized view by setting their
* transient property to true. This must cause the component itself,
* as well as all of that component's children and facets, to be omitted from the saved tree
* structure and component state information.
*
*
*
* This method must also enforce the rule that, for components with non-null ids,
* all components that are descendants of the same nearest {@link NamingContainer} must have
* unique identifiers.
*
*
* @param context {@link FacesContext} for the current request
* @return the serialized view, or null.
* @throws IllegalStateException if more than one component or facet within the same
* {@link NamingContainer} in this view has the same non-null component
* id
* @deprecated this has been replaced by {@link #saveView}. The default implementation calls
* saveView and inspects the return. If the return is an
* Object [], it casts the result to an Object [] wrapping
* the first and second elements in an instance of {@link SerializedView}, which it
* then returns. Otherwise, it returns null
*
*/
public SerializedView saveSerializedView(FacesContext context) {
context.getAttributes().put(IS_CALLED_FROM_API_CLASS, TRUE);
Object stateObj = null;
try {
stateObj = saveView(context);
} finally {
context.getAttributes().remove(IS_CALLED_FROM_API_CLASS);
}
SerializedView result = null;
if (stateObj instanceof Object[]) {
Object[] state = (Object[]) stateObj;
if (state.length == 2) {
result = new SerializedView(state[0], state[1]);
}
}
return result;
}
/**
*
* The functionality of this method is now handled by
* {@link javax.faces.view.StateManagementStrategy#saveView}. Return an opaque
* Object containing sufficient information for this same instance to restore the
* state of the current {@link UIViewRoot} on a subsequent request. The returned object must
* implement java.io.Serializable. If there is no state information to be saved,
* return null instead.
*
*
*
* Components may opt out of being included in the serialized view by setting their
* transient property to true. This must cause the component itself,
* as well as all of that component's children and facets, to be omitted from the saved tree
* structure and component state information.
*
*
*
* This method must also enforce the rule that, for components with non-null ids,
* all components that are descendants of the same nearest {@link NamingContainer} must have
* unique identifiers.
*
*
*
* For backwards compatability with existing StateManager implementations, the
* default implementation of this method calls {@link #saveSerializedView} and creates and
* returns a two element Object array with element zero containing the
* structure property and element one containing the state property of
* the SerializedView.
*
*
* @param context {@link FacesContext} for the current request
* @return the saved view.
* @throws IllegalStateException if more than one component or facet within the same
* {@link NamingContainer} in this view has the same non-null component
* id
* @since 1.2
*/
@Deprecated
public Object saveView(FacesContext context) {
Object stateArray[] = null;
if (!context.getAttributes().containsKey(IS_CALLED_FROM_API_CLASS)) {
SerializedView view = saveSerializedView(context);
if (view != null) {
stateArray = new Object[] { view.getStructure(), view.getState() };
}
}
return stateArray;
}
/**
*
* Convenience method, which must be called by saveSerializedView(), to construct
* and return a Serializable object that represents the structure of the entire
* component tree (including children and facets) of this view.
*
*
*
* Components may opt-out of being included in the tree structure by setting their
* transient property to true. This must cause the component itself,
* as well as all of that component's children and facets, to be omitted from the saved tree
* structure information.
*
*
* @param context {@link FacesContext} for the current request
* @return the tree structure, or null.
* @deprecated the distinction between tree structure and component state is now an
* implementation detail. The default implementation returns null.
*/
protected Object getTreeStructureToSave(FacesContext context) {
return null;
}
/**
*
* Convenience method, which must be called by saveSerializedView(), to construct
* and return a Serializable object that represents the state of all component
* properties, attributes, and attached objects, for the entire component tree (including
* children and facets) of this view.
*
*
*
* Components may opt-out of being included in the component state by setting their
* transient property to true. This must cause the component itself,
* as well as all of that component's children and facets, to be omitted from the saved
* component state information.
*
*
* @param context {@link FacesContext} for the current request
* @return the component state, or null.
* @deprecated the distinction between tree structure and component state is now an
* implementation detail. The default implementation returns null.
*/
protected Object getComponentStateToSave(FacesContext context) {
return null;
}
/**
*
* 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 {@link ResponseStateManager} instance provided by the
* {@link RenderKit} being used to render this view. This method assumes that the caller has
* positioned the {@link ResponseWriter} at the correct position for the saved state to be
* written.
*
*
*
* For backwards compatability with existing StateManager implementations, the
* default implementation of this method checks if the argument is an instance of
* Object [] of length greater than or equal to two. If so, it creates a
* SerializedView instance with the tree structure coming from element zero and the
* component state coming from element one and calls through to
* {@link #writeState(javax.faces.context.FacesContext,javax.faces.application.StateManager.SerializedView)}.
* If not, does nothing.
*
*
* @param context {@link FacesContext} for the current request
* @param state the Serializable state to be written, as returned by {@link #saveSerializedView}
* @throws IOException when an I/O error occurs.
* @since 1.2
*/
public void writeState(FacesContext context, Object state) throws IOException {
if (state != null && state.getClass().isArray() && state.getClass().getComponentType().equals(Object.class)) {
Object stateArray[] = (Object[]) state;
if (stateArray.length == 2) {
SerializedView view = new SerializedView(stateArray[0], stateArray[1]);
writeState(context, view);
}
}
}
/**
*
* Save the state represented in the specified SerializedView isntance, in an
* implementation dependent manner.
*
*
*
* This method must consult the context initialization parameter named by the symbolic constant
* StateManager.STATE_SAVING_METHOD_PARAM_NAME to determine whether state should be
* saved on the client or the server. If not present, client side state saving is assumed.
*
*
*
* If the init parameter indicates that client side state saving should be used, this method
* must delegate the actual writing to the writeState() method of the
* {@link ResponseStateManager} instance provided by the {@link RenderKit} being used to render
* this view. This method assumes that the caller has positioned the {@link ResponseWriter} at
* the correct position for the saved state to be written.
*
*
* @param context {@link FacesContext} for the current request
* @param state the serialized state to be written
* @throws IOException when an I/O error occurs.
* @deprecated This method has been replaced by
* {@link #writeState(javax.faces.context.FacesContext,java.lang.Object)}. The
* default implementation calls the non-deprecated variant of the method passing an
* Object [] as the second argument, where the first element of the
* array is the return from getStructure() and the second is the return
* from getState() on the argument state.
*
*/
public void writeState(FacesContext context, SerializedView state) throws IOException {
if (state != null) {
writeState(context, new Object[] { state.getStructure(), state.getState() });
}
}
// ------------------------------------------------- State Restoring Methods
/**
*
* The functionality of this method is now handled by
* {@link javax.faces.view.StateManagementStrategy#restoreView}. Restore the tree
* structure and the component state of the view for the specified viewId, in an
* implementation dependent manner, and return the restored {@link UIViewRoot}. If there is no
* saved state information available for this viewId, return null
* instead.
*
*
*
* This method must consult the context initialization parameter named by the symbolic constant
* StateManager.STATE_SAVING_METHOD_PARAM_NAME to determine whether state should be
* saved on the client or the server. If not present, client side state saving is assumed.
*
*
*
* If the init parameter indicates that client side state saving should be used, this method
* must call the getTreeStructureToRestore() and (if the previous method call
* returned a non-null value) getComponentStateToRestore() methods of the
* {@link ResponseStateManager} instance provided by the {@link RenderKit} responsible for this
* view.
*
*
* @param context {@link FacesContext} for the current request
* @param viewId View identifier of the view to be restored
* @param renderKitId the renderKitId used to render this response. Must not be
* null.
*
* @return the view root, or null.
* @throws IllegalArgumentException if renderKitId is null.
*/
@Deprecated
public abstract UIViewRoot restoreView(FacesContext context, String viewId, String renderKitId);
/**
*
* Convenience method, which must be called by restoreView(), to construct and
* return a {@link UIViewRoot} instance (populated with children and facets) representing the
* tree structure of the component tree being restored. If no saved state information is
* available, return null instead.
*
*
* @param context {@link FacesContext} for the current request
* @param viewId View identifier of the view to be restored
* @param renderKitId the renderKitId used to render this response. Must not be
* null.
* @return the view root, or null.
* @throws IllegalArgumentException if renderKitId is null.
* @deprecated the distinction between tree structure and component state is now an
* implementation detail. The default implementation returns null.
*/
protected UIViewRoot restoreTreeStructure(FacesContext context, String viewId, String renderKitId) {
return null;
}
/**
*
* Convenience method, which must be called by restoreView(), to restore the
* attributes, properties, and attached objects of all components in the restored component
* tree.
*
*
* @param context {@link FacesContext} for the current request
* @param viewRoot {@link UIViewRoot} returned by a previous call to
* restoreTreeStructure()
* @param renderKitId the renderKitId used to render this response. Must not be
* null.
*
* @throws IllegalArgumentException if renderKitId is null.
* @deprecated the distinction between tree structure and component state is now an
* implementation detail. The default implementation does nothing.
*/
protected void restoreComponentState(FacesContext context, UIViewRoot viewRoot, String renderKitId) {
}
/**
*
* Method to determine if the state is saved on the
* client.
*
*
* @param context the Faces context.
* @return true if and only if the value of the ServletContext init
* parameter named by the value of the constant {@link #STATE_SAVING_METHOD_PARAM_NAME}
* is equal (ignoring case) to the value of
* the constant {@link #STATE_SAVING_METHOD_CLIENT}. false otherwise.
*
* @throws NullPointerException if context is null.
*/
public boolean isSavingStateInClient(FacesContext context) {
if (null != savingStateInClient) {
return savingStateInClient.booleanValue();
}
savingStateInClient = Boolean.FALSE;
String saveStateParam = context.getExternalContext().getInitParameter(STATE_SAVING_METHOD_PARAM_NAME);
if (saveStateParam != null && saveStateParam.equalsIgnoreCase(STATE_SAVING_METHOD_CLIENT)) {
savingStateInClient = Boolean.TRUE;
}
return savingStateInClient.booleanValue();
}
/**
*
* Convenience struct for encapsulating tree structure and component state. This is necessary to
* allow the API to be flexible enough to work in Jakarta Server Pages and non-Jakarta Server Pages environments.
*
*
* @deprecated This class was not marked Serializable in the 1.0 version of the
* spec. It was also not a static inner class, so it can't be made to be
* Serializable. Therefore, it is being deprecated in version 1.2 of
* the spec. The replacement is to use an implementation dependent
* Object.
*/
public class SerializedView extends Object {
private Object structure = null;
private Object state = null;
public SerializedView(Object newStructure, Object newState) {
structure = newStructure;
state = newState;
}
public Object getStructure() {
return structure;
}
public Object getState() {
return state;
}
}
/**
*
* Convenience method to return the view state as a String with no
* RenderKit specific markup.
*
* This default implementation of this method will call
* {@link #saveView(javax.faces.context.FacesContext)} and passing the result to and returning
* the resulting value from
* {@link ResponseStateManager#getViewState(javax.faces.context.FacesContext, Object)}.
*
*
* @param context {@link FacesContext} for the current request
* @return the view state.
* @since 2.0
*/
public String getViewState(FacesContext context) {
Object state = saveView(context);
return context.getRenderKit().getResponseStateManager().getViewState(context, state);
}
}