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EE4J Compatible Implementation for Jakarta Faces API
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/*
* 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 com.sun.faces.facelets.el;
import java.util.logging.Level;
import java.util.logging.Logger;
import com.sun.faces.component.CompositeComponentStackManager;
import com.sun.faces.util.FacesLogger;
import jakarta.el.ELContext;
import jakarta.el.ELException;
import jakarta.el.MethodExpression;
import jakarta.el.MethodInfo;
import jakarta.el.MethodNotFoundException;
import jakarta.el.ValueExpression;
import jakarta.faces.component.UIComponent;
import jakarta.faces.context.FacesContext;
import jakarta.faces.event.AbortProcessingException;
import jakarta.faces.event.ComponentSystemEvent;
import jakarta.faces.event.ComponentSystemEventListener;
import jakarta.faces.event.PostAddToViewEvent;
import jakarta.faces.validator.ValidatorException;
import jakarta.faces.view.Location;
/**
*
* This specialized MethodExpression enables the evaluation of composite component expressions. Instances
* of this expression will be created when
* {@link com.sun.faces.facelets.tag.TagAttributeImpl#getValueExpression(jakarta.faces.view.facelets.FaceletContext, Class)}
* is invoked and the expression represents a composite component expression (i.e. #{cc.[properties]}).
*
*
*
* It's important to note that these MethodExpressions are context sensitive in that they leverage the
* location in which they were referenced in order to push the proper composite component to the evaluation context
* prior to evaluating the expression itself.
*
*
* Here's an example:
*
*
* Using Page test.xhtml
* ---------------------------------
* <ez:comp1 do="#{bean.action}" />
*
*
* comp1.xhtml
* ---------------------------------
* <composite:interface>
* <composite:attribute name="do" method-signature="String f()" required="true" />
* </composite:interface>
* <composite:implementation>
* <ez:nesting>
* <h:commandButton value="Click Me!" action="#{cc.attrs.do} />
* </ez:nesting>
* </composite:implementation>
*
* nesting.xhtml
* ---------------------------------
* <composite:interface />
* <composite:implementation>
* <composite:insertChildren>
* </composite:implementation>
*
*
* When commandButton is clicked, the ContextualCompositeMethodExpression first is looked up
* by {@link com.sun.faces.facelets.tag.TagAttributeImpl.AttributeLookupMethodExpression} which results an instance of
* ContextualCompositeMethodExpression. When this
* ContextualCompositeMethodExpression is invoked, the {@link jakarta.faces.view.Location}
* object necessary to find the proper composite component will be derived from
* source ValueExpression provided at construction time.
*
* Using the derived
* {@link jakarta.faces.view.Location}, we can find the composite component that matches 'owns' the template in which
* the expression was defined in by comparing the path of the Location with the name and library of the
* {@link jakarta.faces.application.Resource} instance associated with each composite component. If a matching composite
* component is found, it will be made available to the EL by calling
* {@link CompositeComponentStackManager#push(jakarta.faces.component.UIComponent)}.
*/
public class ContextualCompositeMethodExpression extends MethodExpression {
private static final long serialVersionUID = -6281398928485392830L;
// Log instance for this class
private static final Logger LOGGER = FacesLogger.FACELETS_EL.getLogger();
private final MethodExpression delegate;
private final ValueExpression source;
private final Location location;
private String ccClientId;
// -------------------------------------------------------- Constructors
public ContextualCompositeMethodExpression(ValueExpression source, MethodExpression delegate) {
this.delegate = delegate;
this.source = source;
location = null;
FacesContext ctx = FacesContext.getCurrentInstance();
UIComponent cc = UIComponent.getCurrentCompositeComponent(ctx);
cc.subscribeToEvent(PostAddToViewEvent.class, new SetClientIdListener(this));
}
public ContextualCompositeMethodExpression(Location location, MethodExpression delegate) {
this.delegate = delegate;
this.location = location;
source = null;
FacesContext ctx = FacesContext.getCurrentInstance();
UIComponent cc = UIComponent.getCurrentCompositeComponent(ctx);
cc.subscribeToEvent(PostAddToViewEvent.class, new SetClientIdListener(this));
}
// ------------------------------------------- Methods from MethodExpression
@Override
public MethodInfo getMethodInfo(ELContext elContext) {
return delegate.getMethodInfo(elContext);
}
@Override
public Object invoke(ELContext elContext, Object[] objects) {
FacesContext ctx = (FacesContext) elContext.getContext(FacesContext.class);
try {
boolean pushed = pushCompositeComponent(ctx);
try {
return delegate.invoke(elContext, objects);
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
} catch (ELException ele) {
/*
* If we got a validator exception it is actually correct to immediately bubble it up.
*/
if (ele.getCause() != null && ele.getCause() instanceof ValidatorException) {
throw (ValidatorException) ele.getCause();
}
if (source != null && ele instanceof MethodNotFoundException) {
// special handling when an ELException handling. This is necessary
// when there are multiple levels of composite component nesting.
// When this happens, we need to evaluate the source expression
// to find and invoke the MethodExpression at the next highest
// nesting level. Is there a cleaner way to detect this case?
try {
Object fallback = source.getValue(elContext);
if (fallback != null && fallback instanceof MethodExpression) {
return ((MethodExpression) fallback).invoke(elContext, objects);
}
} catch (ELException ex) {
/*
* If we got a validator exception it is actually correct to immediately bubble it up.
*/
if (ex.getCause() != null && ex.getCause() instanceof ValidatorException) {
throw (ValidatorException) ex.getCause();
}
if (LOGGER.isLoggable(Level.WARNING)) {
LOGGER.log(Level.WARNING, ele.toString());
LOGGER.log(Level.WARNING, "faces.facelets.el.method.expression.invoke.error: {0} {1}",
new Object[] { ex.toString(), source.getExpressionString() });
}
if (!(ex instanceof MethodNotFoundException)) {
throw ex;
}
}
}
throw ele;
}
}
// ------------------------------------------------- Methods from Expression
@Override
public String getExpressionString() {
return delegate.getExpressionString();
}
@Override
public boolean equals(Object o) {
return delegate.equals(o);
}
@Override
public int hashCode() {
return delegate.hashCode();
}
@Override
public boolean isLiteralText() {
return delegate.isLiteralText();
}
// ----------------------------------------------------- Private Methods
private boolean pushCompositeComponent(FacesContext ctx) {
CompositeComponentStackManager manager = CompositeComponentStackManager.getManager(ctx);
UIComponent foundCc = null;
if (location != null) {
foundCc = manager.findCompositeComponentUsingLocation(ctx, location);
} else {
// We need to obtain the Location of the source expression in order
// to find the composite component that needs to be available within
// the evaluation stack.
if (source instanceof TagValueExpression) {
ValueExpression orig = ((TagValueExpression) source).getWrapped();
if (orig instanceof ContextualCompositeValueExpression) {
foundCc = manager.findCompositeComponentUsingLocation(ctx, ((ContextualCompositeValueExpression) orig).getLocation());
}
}
}
if (null == foundCc) {
foundCc = ctx.getViewRoot().findComponent(ccClientId);
}
return manager.push(foundCc);
}
private void popCompositeComponent(FacesContext ctx) {
CompositeComponentStackManager manager = CompositeComponentStackManager.getManager(ctx);
manager.pop();
}
private class SetClientIdListener implements ComponentSystemEventListener {
private ContextualCompositeMethodExpression ccME;
public SetClientIdListener(ContextualCompositeMethodExpression ccME) {
this.ccME = ccME;
}
@Override
public void processEvent(ComponentSystemEvent event) throws AbortProcessingException {
ccME.ccClientId = event.getComponent().getClientId();
event.getComponent().unsubscribeFromEvent(PostAddToViewEvent.class, this);
}
}
}