Interesting EL expressions
OpenCms comes with several Java beans to provide access to OpenCms-specific functionality in JSPs. In general, if required, an object of each bean could be made available separately in a JSP. Also several tags of the <cms:>-taglib initialize and expose objects of such beans.
Since OpenCms 9.0.1 the variable cms is present in the page scope for each JSP. It makes an object of type org.opencms.jsp.util.CmsJspStandardContextBean available. The object provides a convenient way to access the most important OpenCms functions via JSTL/EL. Thus, in most cases no bean at all has to be included and initialized manually, and also formerly required use of scriptlet code becomes obsolete.
The standard context bean has a very rich interface. In particular, access to several other Java beans shipped with OpenCms is granted. A complete overview of the functionality exposed via the standard context bean can be looked up in the JavaDoc. Look up the documentation of the class CmsJspStandardContextBean. Starting there, you can easily explore the interfaces of all other beans accessible via the standard context bean as well. If you are aware of the naming conventions for Java Beans, you can obtain an overview of the properties available in EL.
Another starting point to get an overview is this documentation page, only listing interesting beans and how to obtain an object of that bean.
Here, we describe only the most important Java beans shipped with OpenCms. We do not aim for completeness when describing the properties of the beans. We also do not cover all beans. In particular, we exclude beans for content access, since they are handled when formatters are explained.
Useful properties in a template
List of properties useful in a template
-
title Get the title property of the currently requested page. Note, that the property has a special behavior for detail pages: Instead of using the title property of the displayed page, the title property of the resource providing the detail content is chosen.
-
isOnlineProject Returns
trueif the request is performed in the “online” project. Otherwise returnsfalse.-
isEditMode Returns
trueif edit mode is enabled. Otherwise returnsfalse.
We exemplify the use of the properties in a template. The tasks are as follows:
- Insert minimized javascript sources only in the online project, for debug reasons use the standard version otherwise
- Set the page title of the web page according to the requested resource.
- Place a special placeholder on top of the page if (and only if) in edit mode
The following code snippet fulfills the three tasks:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<title><c:out value="${cms.title}"/></title>
<meta charset="${cms.requestContext.encoding}">
<!-- meta info etc. -->
<cms:enable-ade/>
<c:choice>
<c:when test="${cms.isOnlineProject}">
<cms:headincludes type="javascript"
defaults="%(link.weak:/.../jquery-1.10.2.min.js)" />
</c:when>
<c:otherwise>
<cms:headincludes type="javascript"
defaults="%(link.weak:/.../jquery-1.10.2.js)" />
</c:otherwise>
</c:choice>
</head>
<body>
<c:if test="${cms.isEditMode}">
<!--=== Placeholder for OpenCms toolbar ===-->
<div style="background: lightgray; height: 35px"> </div>
</c:if>
<!-- Further code for creating the template -->
</body>
</html>Useful properties for localization
OpenCms supports a multi-language design for web pages. Thus, functionality and especially text output might be language specific. Which language to choose should be selected via a locale parameter. The standard context bean provides two choices for such locales:
List of useful properties for localization
-
locale Returns the locale that is specific for the request context. The same locale is returned by
cms.requestContext.locale.-
workplaceLocale Returns the locale configured in the workplace of the current user.
<p>The locale of the request specific locale is "${cms.locale}".</p>
<p>The locale of your workplace is "${cms.workplaceLocale}".</p>
<p>To change the request specific locale, add the parameter "__locale=de" to the url.</p>
<p>The workplace locale is set via the preferences in your OpenCms workplace.</p>Useful properties for formatting elements
It is sometimes useful to adjust formatters or function providers depending on the context. The standard context bean provides the following useful properties:
List of useful properties for formatting elements
-
edited Returns
trueif the element was re-rendered without reloading the whole page, e.g., after editing the element’s content or moving the element on the page. This state might lead to limited functionality of javascript. Therefore, you might display just a “please reload” message.-
enableReload Placing
${cms.enableReload}somewhere in your formatter will result in an automatically page reload when content is edited (or moved to a different container).-
element Returns the currently rendered element.
Return type:org.opencms.xml.containerpage.CmsContainerElementBean-
container Returns the container the currently rendered element is part of.
Return type:org.opencms.xml.containerpage.CmsContainerBean-
detailContent Returns the current detail content, or null if no detail content is requested.
Return type:org.opencms.file.CmsResource(see here)-
detailPageAvailable Returns
trueif a detail page is available for the current element.-
detailRequest Returns
trueif this is a request to a detail page.
Useful properties to access further interesting Java beans
Via the following properties, you obtain objects of the given beans, that are initialized according to the current request.
List of useful properties to access further interesting Java beans
-
requestContext Access to the request context bean
org.opencms.file.CmsRequestContext.-
vfs Access to the VFS access bean
org.opencms.jsp.util.CmsJspVfsAccessBean.
Note that here more properties that return objects of further Java beans are explained. In contrast to the properties listed above, these properties only make sense when formatting elements in container pages.
Useful properties to access further interesting Java beans
List of properties to access further interesting Java beans
-
currentUser Access to the user bean
org.opencms.file.CmsUser.-
currentProject Access to the project bean
org.opencms.file.CmsProject.
The VFS access bean
The VFS access bean provides access to all resources in the OpenCms virtual file system. The bean is used to check if files exist, to read and set properties and permissions, to read XML documents, etc. In summary, you can access every resource in the VFS, read its metadata or access content. To enable such functionality, most properties of the bean return a lazy map that requires the URI of a resource as key to extract a value. If the current user has no access to the resource, or the resource does not exist, the return value will be empty.
When object.property returns a map, use object.property[key] to ask for the value of key key.
Useful properties to explore resources in the VFS
List of useful properties to explore resources in the VFS
-
exists Returns true if a resource, whose URI is given as key, exists.
-
existsXML Returns
trueif a resource, whose URI is given as key, exists and is an XML content or XML page.-
property Given an URI as key, a lazy map with property names as keys and their values as values is returned.
-
propertySearch Like
property, but the returned map also contains inherited values for properties.
The following example shows how to read the “NavText” property of a file and how to access a value in an XML content item.
<%@page taglibs="c" %>
<c:set var="uri" value="${cms.requestContext.uri}" />
<p> The "NavText" property value of the current URI (file
${cms.vfs.resource[uri].name}) is
"${cms.vfs.property[uri]['NavText']}".
</p>
<p> The Text value of a selected Jumbotron XML content is
"${cms.vfs.xml['/demo/.content/jumbotrons/jt_00001.xml'].value.Text}".
</p>Useful properties to access further Java beans
List of useful properties to access further Java beans
-
permissions Access to the permission set bean
org.opencms.security.CmsPermissionSet.-
resource Access to the resource bean
org.opencms.file.CmsResource.-
xml Access to the content access bean
org.opencms.jsp.util.CmsJspContentAccessBean.
Useful properties
List of useful properties
-
guestUser Returns
trueif the user is not logged in.-
fullName Returns “firstname lastname (username)”.
-
firstname Returns the firstname of the user.
-
lastname Returns the lastname of the user.
-
email Returns the email of the user.
-
address Returns the address of the user.
-
institution Returns the institution information of the user.
Useful properties
The resource bean
Each entry in the OpenCms VFS can be considered as a resource. The resource bean allows accessing metadata of such resources, such as properties, attributes, version, name, etc.
Useful properties
List of useful properties
-
dateCreated Returns the date of the creation of this resource.
-
dateReleased Returns the release date of this resource.
-
dateExpired Returns the expiration date of this resource.
-
dateLastModified Returns the date of the last modification of this resource.
-
dateContent Returns the date of the last modification of the content of this resource.
-
name Returns the file name of this resource without parent folders, for example “index.html”.