javax.faces.component.UIViewAction Maven / Gradle / Ivy
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* Copyright 2011, Red Hat, Inc., and individual contributors
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* full listing of individual contributors.
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package javax.faces.component;
import java.util.Map;
import javax.el.MethodExpression;
import javax.faces.FacesException;
import javax.faces.application.NavigationHandler;
import javax.faces.context.FacesContext;
import javax.faces.context.FacesContextWrapper;
import javax.faces.el.MethodBinding;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ActionEvent;
import javax.faces.event.ActionListener;
import javax.faces.event.FacesEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PreRenderViewEvent;
import javax.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 javax.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 ActionSource2}, any actions
* that one would normally take on a component that implements
* ActionSource2, such as {@link UICommand}, are valid for
* instances of this class. Instances of this class participate in the
* regular JSF 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
* JSF 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 JSF.7.4.2 Default
* NavigationHandler Algorithm, for the discussion 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 ActionSource2 {
// ------------------------------------------------------ Manifest Constants
/**
*
* The standard component type for this component.
*
*/
public static final String COMPONENT_TYPE = "javax.faces.ViewAction";
/**
*
* The standard component family for this component.
*
*/
public static final String COMPONENT_FAMILY = "javax.faces.ViewAction";
private static final String UIVIEWACTION_BROADCAST = "javax.faces.ViewAction.broadcast";
private static final String UIVIEWACTION_EVENT_COUNT = "javax.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;
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Deprecated
@Override
public MethodBinding getAction() {
MethodBinding result = null;
MethodExpression me;
if (null != (me = getActionExpression())) {
result = new MethodBindingMethodExpressionAdapter(me);
}
return result;
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Deprecated
@SuppressWarnings("deprecation")
@Override
public void setAction(final MethodBinding action) {
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Deprecated
@SuppressWarnings("deprecation")
@Override
public MethodBinding getActionListener() {
throw new UnsupportedOperationException("Not supported.");
}
/**
* {@inheritDoc}
*
* @since 2.2
*/
@Deprecated
@SuppressWarnings("deprecation")
@Override
public void setActionListener(final MethodBinding actionListener) {
throw new UnsupportedOperationException("Not supported.");
}
/**
* If the value of the component's
* immediate attribute is true, the action
* will be invoked during the Apply Request Values JSF
* 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.toString() + "]");
}
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);
}
/**
* Return true if this
* component should take the actions specified in the {@link
* #decode} method.
*
* @return true if it should be rendered, 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
* javax.faces.application.Application}. Wrap the current {@link
* FacesContext} in an implementation of {@link
* javax.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
* javax.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 JavaServer 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 JSF 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 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("javax.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());
}
}
}