com.sun.faces.facelets.el.ContextualCompositeValueExpression Maven / Gradle / Ivy
/*
* 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 com.sun.faces.facelets.el;
import com.sun.faces.component.CompositeComponentStackManager;
import javax.el.ValueExpression;
import javax.el.ELContext;
import javax.faces.view.Location;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
/**
*
* This specialized ValueExpression enables the evaluation of
* composite component expressions. Instances of this expression will be
* created when {@link com.sun.faces.facelets.tag.TagAttributeImpl#getValueExpression(javax.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 ValueExpressions 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 greeting="Hello!" />
*
*
* comp1.xhtml
* ---------------------------------
* <composite:interface>
* <composite:attribute name="greeting" type="java.lang.String" required="true" />
* </composite:interface>
* <composite:implementation>
* <ez:nesting>
* <h:outputText value="#{cc.attrs.greetings}" />
* </ez:nesting>
* </composite:implementation>
*
* nesting.xhtml
* ---------------------------------
* <composite:interface />
* <composite:implementation>
* <composite:insertChildren>
* </composite:implementation>
*
*
*
* In the above example, there will be two composite components available to
* the runtime: ez:comp1 and ez:nesting.
*
*
*
* When <h:outputText value="#{cc.attrs.greeting}" />, prior to attempting
* to evaluate the expression, the {@link Location} object will be used to
* find the composite component that '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 javax.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(javax.faces.component.UIComponent)}.
*
*/
public final class ContextualCompositeValueExpression extends ValueExpression {
private static final long serialVersionUID = -2637560875633456679L;
private ValueExpression originalVE;
private Location location;
// ---------------------------------------------------- Constructors
/* For serialization purposes */
public ContextualCompositeValueExpression() { }
public ContextualCompositeValueExpression(Location location,
ValueExpression originalVE) {
this.originalVE = originalVE;
this.location = location;
}
// ------------------------------------ Methods from ValueExpression
@Override
public Object getValue(ELContext elContext) {
FacesContext ctx = (FacesContext) elContext.getContext(FacesContext.class);
boolean pushed = pushCompositeComponent(ctx);
try {
return originalVE.getValue(elContext);
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
}
@Override
public void setValue(ELContext elContext, Object o) {
FacesContext ctx = (FacesContext) elContext.getContext(FacesContext.class);
boolean pushed = pushCompositeComponent(ctx);
try {
originalVE.setValue(elContext, o);
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
}
@Override
public boolean isReadOnly(ELContext elContext) {
FacesContext ctx = (FacesContext) elContext.getContext(FacesContext.class);
boolean pushed = pushCompositeComponent(ctx);
try {
return originalVE.isReadOnly(elContext);
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
}
@Override
public Class getType(ELContext elContext) {
FacesContext ctx = (FacesContext) elContext.getContext(FacesContext.class);
boolean pushed = pushCompositeComponent(ctx);
try {
return originalVE.getType(elContext);
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
}
@Override
public Class getExpectedType() {
FacesContext ctx = FacesContext.getCurrentInstance();
boolean pushed = pushCompositeComponent(ctx);
try {
return originalVE.getExpectedType();
} finally {
if (pushed) {
popCompositeComponent(ctx);
}
}
}
// --------------------------------------------- Methods from Expression
@Override
public String getExpressionString() {
return originalVE.getExpressionString();
}
@SuppressWarnings({"EqualsWhichDoesntCheckParameterClass"})
@Override
public boolean equals(Object o) {
return originalVE.equals(o);
}
@Override
public int hashCode() {
return originalVE.hashCode();
}
@Override
public boolean isLiteralText() {
return originalVE.isLiteralText();
}
@Override
public String toString() {
return originalVE.toString();
}
// ------------------------------------------------------ Public Methods
/**
* @return the {@link Location} of this ValueExpression
*/
public Location getLocation() {
return location;
}
// ----------------------------------------------------- Private Methods
private boolean pushCompositeComponent(FacesContext ctx) {
CompositeComponentStackManager manager =
CompositeComponentStackManager.getManager(ctx);
UIComponent cc = manager.findCompositeComponentUsingLocation(ctx, location);
return manager.push(cc);
}
private void popCompositeComponent(FacesContext ctx) {
CompositeComponentStackManager manager =
CompositeComponentStackManager.getManager(ctx);
manager.pop();
}
} // END ContextualCompositeValueExpression