jakarta.faces.component.UIViewAction Maven / Gradle / Ivy
Show all versions of jakarta.faces Show documentation
/*
* Copyright (c) 1997, 2020 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 jakarta.faces.component;
import java.util.Map;
import jakarta.el.MethodExpression;
import jakarta.faces.FacesException;
import jakarta.faces.application.NavigationHandler;
import jakarta.faces.context.FacesContext;
import jakarta.faces.context.FacesContextWrapper;
import jakarta.faces.event.AbortProcessingException;
import jakarta.faces.event.ActionEvent;
import jakarta.faces.event.ActionListener;
import jakarta.faces.event.FacesEvent;
import jakarta.faces.event.PhaseId;
import jakarta.faces.event.PreRenderViewEvent;
import jakarta.faces.view.ViewMetadata;
/**
*
*
* UIViewAction represents a method invocation that occurs during the
* request processing lifecycle, usually in response to an initial request, as opposed to a postback.
*
*
*
*
*
* The {@link jakarta.faces.view.ViewDeclarationLanguage} implementation must cause an instance of this component to be
* placed in the view for each occurrence of an <f:viewAction
* /> element placed inside of an <f:metadata
* /> element. The user must place <f:metadata
* /> as a direct child of the UIViewRoot.
*
*
*
* Because this class implements {@link ActionSource}, any actions that one would normally take on a component that
* implements ActionSource, such as {@link UICommand}, are valid for instances of this class. Instances of
* this class participate in the regular Jakarta Faces lifecycle, including on Ajax requests.
*
*
*
* The purpose of this component is to provide a light-weight front-controller solution for executing code upon the
* loading of a Jakarta Faces view to support the integration of system services, content retrieval, view
* management, and navigation. This functionality is especially useful for non-faces (initial) requests.
*
*
*
* The most common use case for this component is to take actions necessary for a particular view, often with the help
* of one or more {@link UIViewParameter}s.
*
*
*
* The {@link NavigationHandler} is consulted after the action is invoked to carry out the navigation case that matches
* the action signature and outcome. If a navigation case is matched that causes the new viewId to be different from the
* current viewId, the runtime must force a redirect to that matched navigation case with different viewId, regardless
* of whether or not the matched navigation case with different viewId called for a redirect.
* If the navigation will result in a flow transition, the appropriate metadata must be
* included in the query string for the redirect.
* See section 7.4.2 "Default NavigationHandler Algorithm" of the Jakarta Faces Specification Document, for the
* specification of how to handle {@code <redirect />} cases.
*
*
*
* It's important to note that the full component tree is not built before the UIViewAction components are processed on
* an non-faces (initial) request. Rather, the component tree only contains the {@link ViewMetadata}, an important part
* of the optimization of this component and what sets it apart from a {@link PreRenderViewEvent} listener.
*
*
*
*
* @since 2.2
*/
public class UIViewAction extends UIComponentBase implements ActionSource {
// ------------------------------------------------------ Manifest Constants
/**
*
* The standard component type for this component.
*
*/
public static final String COMPONENT_TYPE = "jakarta.faces.ViewAction";
/**
*
* The standard component family for this component.
*
*/
public static final String COMPONENT_FAMILY = "jakarta.faces.ViewAction";
private static final String UIVIEWACTION_BROADCAST = "jakarta.faces.ViewAction.broadcast";
private static final String UIVIEWACTION_EVENT_COUNT = "jakarta.faces.ViewAction.eventCount";
/**
* Properties that are tracked by state saving.
*/
enum PropertyKeys {
onPostback, actionExpression, immediate, phase, renderedAttr("if");
private String name;
PropertyKeys() {
}
PropertyKeys(final String name) {
this.name = name;
}
@Override
public String toString() {
return name != null ? name : super.toString();
}
}
// ------------------------------------------------------------ Constructors
/**
*
* Create a new {@link UIViewAction} instance with default property values.
*
*/
public UIViewAction() {
super();
setRendererType(null);
}
// -------------------------------------------------------------- Properties
@Override
public String getFamily() {
return COMPONENT_FAMILY;
}
private void incrementEventCount(FacesContext context) {
Map attrs = context.getAttributes();
Integer count = (Integer) attrs.get(UIVIEWACTION_EVENT_COUNT);
if (null == count) {
attrs.put(UIVIEWACTION_EVENT_COUNT, 1);
} else {
attrs.put(UIVIEWACTION_EVENT_COUNT, count + 1);
}
}
private boolean decrementEventCountAndReturnTrueIfZero(FacesContext context) {
boolean result = true;
Map attrs = context.getAttributes();
Integer count = (Integer) attrs.get(UIVIEWACTION_EVENT_COUNT);
if (null != count) {
count = count - 1;
if (count < 1) {
attrs.remove(UIVIEWACTION_EVENT_COUNT);
result = true;
} else {
attrs.put(UIVIEWACTION_EVENT_COUNT, count);
result = false;
}
}
return result;
}
/**
*
* If the value of the component's immediate attribute is true, the action will be invoked
* during the Apply Request Values Jakarta Faces lifecycle phase. Otherwise, the action will be invoked
* during the Invoke Application phase, the default behavior. The phase can be set explicitly in the
* phase attribute, which takes precedence over the immediate attribute.
*
*
* @since 2.2
*/
@Override
public boolean isImmediate() {
return (Boolean) getStateHelper().eval(PropertyKeys.immediate, false);
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Override
public void setImmediate(final boolean immediate) {
getStateHelper().put(PropertyKeys.immediate, immediate);
}
/**
*
* Returns the name of the lifecycle phase in which the action is to be queued.
*
*
* @return the phase (as string).
* @since 2.2
*/
public String getPhase() {
PhaseId myPhaseId = getPhaseId();
String result = null;
if (null != myPhaseId) {
result = myPhaseId.getName();
}
return result;
}
/**
*
* Attempt to set the lifecycle phase in which this instance will queue its {@link ActionEvent}. Pass the argument
* phase to {@link PhaseId#phaseIdValueOf}. If the result is not one of the following values,
* FacesException must be thrown.
*
*
*
*
* -
*
* {@link PhaseId#APPLY_REQUEST_VALUES}
*
*
* -
*
* {@link PhaseId#PROCESS_VALIDATIONS}
*
*
* -
*
* {@link PhaseId#UPDATE_MODEL_VALUES}
*
*
* -
*
* {@link PhaseId#INVOKE_APPLICATION}
*
*
*
*
*
*
* If set, this value takes precedence over the immediate flag.
*
*
* @param phase the phase id (as string value).
* @since 2.2
*/
public void setPhase(final String phase) {
PhaseId myPhaseId = PhaseId.phaseIdValueOf(phase);
if (PhaseId.ANY_PHASE.equals(myPhaseId) || PhaseId.RESTORE_VIEW.equals(myPhaseId) || PhaseId.RENDER_RESPONSE.equals(myPhaseId)) {
throw new FacesException("View actions cannot be executed in specified phase: [" + myPhaseId + "]");
}
getStateHelper().put(PropertyKeys.phase, myPhaseId.getName());
}
private void setIsProcessingUIViewActionBroadcast(FacesContext context, boolean value) {
Map attrs = context.getAttributes();
if (value) {
attrs.put(UIVIEWACTION_BROADCAST, Boolean.TRUE);
} else {
attrs.remove(UIVIEWACTION_BROADCAST);
}
}
/**
*
* Returns true if the current request processing lifecycle is in the midst of processing the broadcast of
* an event queued during a call to {@link #decode}. The implementation of {@link #broadcast} is responsible for
* ensuring that calls to this method accurately reflect this fact.
*
*
* @param context {@link FacesContext} for the current request
* @return true is currently processing broadcast, false otherwise.
* @since 2.2
*
*/
public static boolean isProcessingBroadcast(FacesContext context) {
boolean result = context.getAttributes().containsKey(UIVIEWACTION_BROADCAST);
return result;
}
private PhaseId getPhaseId() {
PhaseId myPhaseId = null;
String phaseIdString = (String) getStateHelper().eval(PropertyKeys.phase);
if (phaseIdString != null) {
myPhaseId = PhaseId.phaseIdValueOf(phaseIdString);
}
return myPhaseId;
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Override
public void addActionListener(final ActionListener listener) {
addFacesListener(listener);
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Override
public ActionListener[] getActionListeners() {
ActionListener[] al = (ActionListener[]) getFacesListeners(ActionListener.class);
return al;
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Override
public void removeActionListener(final ActionListener listener) {
removeFacesListener(listener);
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Override
public MethodExpression getActionExpression() {
return (MethodExpression) getStateHelper().get(PropertyKeys.actionExpression);
}
/**
* {@inheritDoc}
*
* @param actionExpression the action expression.
* @since 2.2
*/
@Override
public void setActionExpression(final MethodExpression actionExpression) {
getStateHelper().put(PropertyKeys.actionExpression, actionExpression);
}
/**
*
* If true this component will operate on postback.
*
*
* @return true if operating upon postback, false otherwise.
* @since 2.2
*/
public boolean isOnPostback() {
return (Boolean) getStateHelper().eval(PropertyKeys.onPostback, false);
}
/**
*
* Controls whether or not this component operates on postback.
*
*
* @param onPostback the onPostback flag.
* @since 2.2
*/
public void setOnPostback(final boolean onPostback) {
getStateHelper().put(PropertyKeys.onPostback, onPostback);
}
/**
*
* Returns the if property of this component. If true
* then this component should take the actions specified in the {@link #decode} method.
*
*
* @return true if it should take the actions,
* false otherwise.
* @since 2.2
*/
@Override
public boolean isRendered() {
return (Boolean) getStateHelper().eval(PropertyKeys.renderedAttr, true);
}
/**
*
* Sets the if property of this component.
*
*
* @param condition the new value of the property.
*
* @since 2.2
*/
@Override
public void setRendered(final boolean condition) {
getStateHelper().put(PropertyKeys.renderedAttr, condition);
}
// ----------------------------------------------------- UIComponent Methods
/**
*
* Enable the method invocation specified by this component instance to return a value that performs navigation, similar
* in spirit to {@link UICommand#broadcast}.
*
*
*
*
*
* Take no action and return immediately if any of the following conditions are true.
*
*
*
*
* -
*
* The response has already been marked as complete.
*
*
*
* -
*
* The current UIViewRoot is different from the event's source's UIViewRoot.
*
*
*
*
*
*
* Save a local reference to the viewId of the current UIViewRoot. For discussion, let this reference be
* viewIdBeforeAction.
*
*
*
* Obtain the {@link ActionListener} from the {@link jakarta.faces.application.Application}. Wrap the current
* {@link FacesContext} in an implementation of {@link jakarta.faces.context.FacesContextWrapper} that overrides the
* {@link FacesContext#renderResponse} method such that it takes no action. Set the current FacesContext to
* be the FacesContextWrapper instance. Make it so a call to {@link #isProcessingBroadcast} on the current
* FacesContext will return true. This is necessary because the
* {@link jakarta.faces.application.NavigationHandler} will call this method to determine if the navigation is happening
* as the result of a UIViewAction. Invoke {@link ActionListener#processAction}. In a finally
* block, restore the original FacesContext, make it so a call to {@link #isProcessingBroadcast} on the
* current context will return false and discard the wrapper.
*
*
*
* If the response has been marked as complete during the invocation of processAction(), take no further
* action and return. Otherwise, compare viewIdBeforeAction with the viewId of the UIViewRoot on
* the FacesContext after the invocation of processAction(). If the two viewIds are the same
* and no more UIViewAction events have been queued by a call to {@link #decode}, call
* {@link FacesContext#renderResponse} and return. It is possible to detect the case where no more
* UIViewAction events have been queued because the number of such events queued has been noted in the
* specification for {@link #decode}. Otherwise, execute the lifecycle on the new UIViewRoot.
*
*
*
*
* @param event {@link FacesEvent} to be broadcast
*
* @throws AbortProcessingException Signal the Jakarta Faces implementation that no further processing on the
* current event should be performed
* @throws IllegalArgumentException if the implementation class of this {@link FacesEvent} is not supported by this
* component
* @throws NullPointerException if event is null
*
* @since 2.2
*/
@Override
public void broadcast(final FacesEvent event) throws AbortProcessingException {
super.broadcast(event);
FacesContext context = event.getFacesContext();
if (!(event instanceof ActionEvent)) {
throw new IllegalArgumentException();
}
// OPEN QUESTION: should we consider a navigation to the same view as a
// no-op navigation?
// only proceed if the response has not been marked complete and
// navigation to another view has not occurred
if (!context.getResponseComplete() && context.getViewRoot() == getViewRootOf(event)) {
ActionListener listener = context.getApplication().getActionListener();
if (listener != null) {
boolean hasMoreViewActionEvents = false;
UIViewRoot viewRootBefore = context.getViewRoot();
assert null != viewRootBefore;
InstrumentedFacesContext instrumentedContext = null;
try {
instrumentedContext = new InstrumentedFacesContext(context);
setIsProcessingUIViewActionBroadcast(context, true);
// defer the call to renderResponse() that happens in
// ActionListener#processAction(ActionEvent)
instrumentedContext.disableRenderResponseControl().set();
listener.processAction((ActionEvent) event);
hasMoreViewActionEvents = !decrementEventCountAndReturnTrueIfZero(context);
} finally {
setIsProcessingUIViewActionBroadcast(context, false);
if (null != instrumentedContext) {
instrumentedContext.restore();
}
}
// if the response is marked complete, the story is over
if (!context.getResponseComplete()) {
UIViewRoot viewRootAfter = context.getViewRoot();
assert null != viewRootAfter;
// if the view id changed as a result of navigation, then
// execute the Jakarta Faces lifecycle for the new view
// id
String viewIdBefore = viewRootBefore.getViewId();
String viewIdAfter = viewRootAfter.getViewId();
assert null != viewIdBefore && null != viewIdAfter;
boolean viewIdsSame = viewIdBefore.equals(viewIdAfter);
if (viewIdsSame && !hasMoreViewActionEvents) {
// apply the deferred call (relevant when immediate is true)
context.renderResponse();
}
}
}
}
}
/**
*
* Override behavior from the superclass to queue an {@link ActionEvent} that may result in the invocation of the
* action or any actionListeners that may be associated with this instance.
*
*
*
*
*
* Take no action if any of the following conditions are true:
*
*
*
*
* -
*
* The current request is a postback and the instance has been configured to not operate on postback. See
* {@link #isOnPostback}.
*
*
*
* -
*
* The condition stated in the if property evaluates to false. See {@link #isRendered}
*
* .
*
*
*
*
* Instantiate an {@link ActionEvent}, passing this component instance as the source. Set the phaseId
* property of the ActionEvent as follows.
*
*
*
*
* -
*
* If this component instance has been configured with a specific lifecycle phase with a call to {@link #setPhase} use
* that as the phaseId
*
*
*
* -
*
* If the value of the immediate property is true, use {@link PhaseId#APPLY_REQUEST_VALUES}.
*
*
*
* -
*
* Otherwise, use {@link PhaseId#INVOKE_APPLICATION}.
*
*
*
*
*
*
* Queue the event with a call to {@link #queueEvent}. Keep track of the number of events that are queued in this way on
* this run through the lifecycle. This information is necessary during processing in {@link #broadcast}.
*
*
*
*
* @since 2.2
*
*/
@Override
public void decode(final FacesContext context) {
if (context == null) {
throw new NullPointerException();
}
if (context.isPostback() && !isOnPostback() || !isRendered()) {
return;
}
ActionEvent e = new ActionEvent(context, this);
PhaseId phaseId = getPhaseId();
if (phaseId != null) {
e.setPhaseId(phaseId);
} else if (isImmediate()) {
e.setPhaseId(PhaseId.APPLY_REQUEST_VALUES);
} else {
e.setPhaseId(PhaseId.INVOKE_APPLICATION);
}
incrementEventCount(context);
queueEvent(e);
}
private UIViewRoot getViewRootOf(final FacesEvent e) {
UIComponent c = e.getComponent();
do {
if (c instanceof UIViewRoot) {
return (UIViewRoot) c;
}
c = c.getParent();
} while (c != null);
return null;
}
/**
* A FacesContext delegator that gives us the necessary controls over the FacesContext to allow the execution of the
* lifecycle to accomodate the UIViewAction sequence.
*/
private static class InstrumentedFacesContext extends FacesContextWrapper {
private boolean viewRootCleared = false;
private boolean renderedResponseControlDisabled = false;
private Boolean postback = null;
public InstrumentedFacesContext(final FacesContext wrapped) {
super(wrapped);
}
@Override
public UIViewRoot getViewRoot() {
if (viewRootCleared) {
return null;
}
return super.getViewRoot();
}
@Override
public void setViewRoot(final UIViewRoot viewRoot) {
viewRootCleared = false;
super.setViewRoot(viewRoot);
}
@Override
public boolean isPostback() {
return postback == null ? super.isPostback() : postback;
}
@Override
public void renderResponse() {
if (!renderedResponseControlDisabled) {
super.renderResponse();
}
}
/**
* Make it look like we have dispatched a request using the include method.
*/
public InstrumentedFacesContext pushViewIntoRequestMap() {
getExternalContext().getRequestMap().put("jakarta.servlet.include.servlet_path", super.getViewRoot().getViewId());
return this;
}
public InstrumentedFacesContext clearPostback() {
postback = false;
return this;
}
public InstrumentedFacesContext clearViewRoot() {
viewRootCleared = true;
return this;
}
public InstrumentedFacesContext disableRenderResponseControl() {
renderedResponseControlDisabled = true;
return this;
}
public void set() {
setCurrentInstance(this);
}
public void restore() {
setCurrentInstance(getWrapped());
}
}
}