com.sun.jsftemplating.layout.descriptors.LayoutIf Maven / Gradle / Ivy
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the License). You may not use this file except in
* compliance with the License.
*
* You can obtain a copy of the license at
* https://jsftemplating.dev.java.net/cddl1.html or
* jsftemplating/cddl1.txt.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* Header Notice in each file and include the License file
* at jsftemplating/cddl1.txt.
* If applicable, add the following below the CDDL Header,
* with the fields enclosed by brackets [] replaced by
* you own identifying information:
* "Portions Copyrighted [year] [name of copyright owner]"
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
*/
package com.sun.jsftemplating.layout.descriptors;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import com.sun.jsftemplating.el.PermissionChecker;
import com.sun.jsftemplating.layout.LayoutDefinitionManager;
/**
* This class defines a LayoutIf {@link LayoutElement}. The LayoutIf
* provides the functionality necessary to conditionally display a portion
* of the layout tree. The condition is a boolean equation and may use
* "$...{...}" type expressions to substitute in values.
*
* Depending on its environment, this {@link LayoutElement} can represent
* an {@link com.sun.jsftemplating.component.If} UIComponent
* or simply exist as a {@link LayoutElement}. When its {@link #encode}
* method is called, the if functionality will act as a
* {@link LayoutElement}. When the
* {@link LayoutComponent#getChild(FacesContext, UIComponent)} method is
* called, it will create an {@link com.sun.jsftemplating.component.If}
* UIComponent.
*
* @see com.sun.jsftemplating.el.VariableResolver
* @see com.sun.jsftemplating.el.PermissionChecker
*
* @author Ken Paulsen ([email protected])
*/
public class LayoutIf extends LayoutComponent {
private static final long serialVersionUID = 1L;
/**
* Constructor.
*/
public LayoutIf(LayoutElement parent, String condition) {
this(parent, condition,
LayoutDefinitionManager.getGlobalComponentType(null, "if"));
}
/**
* This constructor may be used by subclasses which wish to provide
* an alternate {@link ComponentType}. The {@link ComponentType} is
* used to instantiate an {@link com.sun.jsftemplating.component.If}
* UIComponent (or whatever the given
* {@link ComponentType} specifies). This occurs when this
* {@link LayoutElement} is nested inside a {@link LayoutComponent}.
* It must create a UIComponent in order to ensure it
* is executed because during rendering there is no other way to get
* control to perform the functionality provided by this
* {@link LayoutElement}.
*/
protected LayoutIf(LayoutElement parent, String condition, ComponentType type) {
super(parent, (String) null, type);
addOption("condition", condition);
if (condition.equals("$property{condition}")) {
_doubleEval = true;
}
}
// FIXME: getHandlers() may need to be overriden to prevent beforeEncode/afterEncode from being called multiple times in some cases. I may also need to explicitly invoke these Handlers in some cases (in the Component??); See LayoutForEach for example of what may need to be done...
/**
* This method returns true if the condition of this LayoutIf is met,
* false otherwise. This provides the functionality for conditionally
* displaying a portion of the layout tree.
*
* @param ctx The FacesContext
* @param comp The UIComponent
*
* @return true if children are to be rendered, false otherwise.
*/
public boolean encodeThis(FacesContext ctx, UIComponent comp) {
PermissionChecker checker = new PermissionChecker(
this, comp, (_doubleEval) ?
((String) getEvaluatedOption(ctx, "condition", comp)) :
((String) getOption("condition")));
return checker.hasPermission();
}
/**
* This flag is set to true when the condition equals
* "$property{condition}". This is a special case where the value to
* be evaluated is not $property{condition}, but rather the value of
* this expression. This requires double evaluation to correct
* interpret the expression. For now this is a hack for this case
* only. In the future we may want to support an $eval{} or something
* more general syntax for doing this declaratively.
*
* See LayoutForEach also.
*/
private boolean _doubleEval = false;
}