The ability to relate assets is one of the most powerful features of Liferay’s asset framework. By relating assets, you can connect individual pieces of content across your site or portal. This helps your users discover related content, particularly when there’s an abundance of other available content. For example, assets related to a Blog entry appear alongside that entry in the Blogs portlet.
This tutorial shows you how to provide a way for authors to relate content. This tutorial assumes that you’ve asset enabled your portlet. A custom Insults portlet is used as an example. After all, users of such a portlet would want to relate their insults to all kinds of content! The completed Insults portlet code that uses this feature is on Github. Now go ahead and get started relating your assets!
First, you must make some modifications to your portlet’s service layer. You
must implement persisting your entity’s asset relationships. In your portlet’s
service.xml, put the following line of code below any finder method elements
and then run
<reference package-path="com.liferay.portlet.asset" entity="AssetLink" />
Next, you need to modify the
update- methods in your
-LocalServiceImpl to persist the asset relationships. You’ll use your
assetLinkLocalService instance variable to execute
persistence actions. When you add and update assets, you must invoke the
updateInsult methods of
InsultLocalServiceImpl both utilize the
updateLinks via your instance variable
assetLinkLocalService. Here’s the
updateLinks invocation in the example Insults portlet’s
assetLinkLocalService.updateLinks( userId, assetEntry.getEntryId(), serviceContext.getAssetLinkEntryIds(), AssetLinkConstants.TYPE_RELATED);
To call the
updateLinks method, you need to pass in the current user’s ID, the
asset entry’s ID, the ID’s of the asset link entries, and the link type. You
should invoke this method after creating the asset entry. You can assign to an
AssetEntry variable (e.g., one called
assetEntry) the value returned from
assetEntryLocalService.updateEntry. That way you can get the asset
entry’s ID for updating its asset links. Lastly, in order to specify the link
type parameter, make sure to import
delete- method, you must delete the asset’s
relationships before deleting the asset. For example, the Insults portlet
deletes the asset link relationships using the following code:
AssetEntry assetEntry = assetEntryLocalService.fetchEntry( Insult.class.getName(), insultId); assetLinkLocalService.deleteLinks(assetEntry.getEntryId());
delete- method can look similar, except it requires your entity’s class
name and your entity’s ID, instead of the
Insult class and its ID variable
insultId that are used in the above code.
Super! Now your portlet’s service layer can handle related assets. Even so, there’s still nothing in your portlet’s UI that lets your users to relate assets. You’ll take care of that in the next step.
You typically implement the UI for linking assets in the JSP that you provide
users the ability to create and edit your entity, This way only content creators
can relate other assets to the entity. In the Insults portlet, for example,
assets can only be related from its
Related assets are implemented in the JSP by using the Liferay UI tag
liferay-ui:input-asset-links inside of a collapsible panel. This code is
placed inside the
aui:fieldset tags of the JSP. The panel and
liferay-ui:input-asset-links tag from the example Insults portlet is shown
<liferay-ui:panel defaultState="closed" extended="<%= false %>" id="insultAssetLinksPanel" persistState="<%= true %>" title="related-assets"> <aui:fieldset> <liferay-ui:input-asset-links className="<%= Insult.class.getName() %>" classPK="<%= insultId %>" /> </aui:fieldset> </liferay-ui:panel>
You can use similar code, replacing the
insultId references with
your portlet’s entity class and entity ID variable. Your content authors are
able to relate assets once you add this code and redeploy your portlet.
The following screenshot shows the Related Assets menu of the Insults portlet. Note that it is contained in a collapsible panel titled Related Assets.
Even though you’ve provided a way for authors to assign related assets, the
Related Assets menu shows your entity’s fully qualified class name, instead of a
more concise name. To replace the long fully qualified class name shown in the
menu with a simplified name for your entity, add a language key that uses the
fully qualified class name as the key’s name and the new simplified name as the
key’s value. Put the language key in file
docroot/WEB-INF/src/content/Language.properties in your portlet. You can refer
to a tutorial here
for more documentation on using language properties.
Here’s a language key to simplify the label for the
Insult entity class used
in the example:
Upon redeploying your portlet, the value you assigned to the fully qualified
class name in your
Language.properties file shows in the Related Assets menu:
Awesome! Now content creators and editors can relate the assets of your portlet. The next thing you need to do is reveal any such related assets to the rest of your portlet’s users. After all, you don’t want to give everyone edit access just so they can view related assets!
You can show related assets in your portlet’s view of that entity or, if you’ve implemented asset rendering for your custom entity, you can show related assets in the full content view of your entity for users to view in an Asset Publisher portlet.
As an example, the Insult portlet’s view JSP file
shows an insult entity and links to all of its related assets. This section
shows you how to access an entity’s asset entry in your entity’s view JSP and
how to display links to its related assets. When you finish, users can click on
the entity instances in your portlet to view any related assets.
In your entity’s view JSP you can use
ParamUtil to get the ID of the entity
from the render request. Then you can create an entity object using your
-LocalServiceUtil class. You can use an entity instance object to get the
AssetEntry object associated with it.
<% long insultId = ParamUtil.getLong(renderRequest, "insultId"); Insult ins = InsultLocalServiceUtil.getInsult(insultId); AssetEntry assetEntry = AssetEntryLocalServiceUtil.getEntry(Insult.class.getName(), ins.getInsultId()); %>
To show the entity’s related assets you use the
You use in your entity’s class to get it’s class name and the variable holding
your instance object to return the its ID. The example code below uses the
example entity class
Insult and an instance object variable called
<liferay-ui:asset-links assetEntryId="<%=(assetEntry != null) ? assetEntry.getEntryId() : 0%>" className="<%=Insult.class.getName()%>" classPK="<%=ins.getInsultId()%>" />
Go ahead and use a the
liferay-ui:asset-links tag in your JSP. Great! Now you
have the JSP that lets your users view related assets.
If you’ve already connected your portlet’s view to the view JSP for your entity, you’ve completed the tutorial. You can otherwise follow the remainder of this tutorial to learn how to implement that connection.
Now that you’ve implemented showing off this asset feature, you must connect
your portlet’s main view JSP to your entity’s view JSP. If your main view JSP
uses a search container to list your entity instances, you can insert a
portlet:renderURL tag just after the
For example, in the Insults portlet’s
it looks like this:
<liferay-ui:search-container-row className="com.sample.portlet.insults.model.Insult" keyProperty="insultId" modelVar="insult" escapedModel="<%= true %>" > <portlet:renderURL windowState="maximized" var="rowURL"> <portlet:param name="mvcPath" value="/html/insult/view_insult.jsp" /> <portlet:param name="insultId" value="<%= String.valueOf(insult.getInsultId()) %>" /> </portlet:renderURL>
Next, add to the first search container column an
href attribute with the
value of the URL you just created in the
portlet:renderURL tag. For example,
the value of
href that corresponds with the render URL created above is
"<%=rowURL %>". Your
search-container-column-text tag can look similar to
<liferay-ui:search-container-column-text name="Insult" value="<%= insult.getInsultString() %>" href="<%=rowURL %>" />
Now, redeploy your portlet and refresh the page so that your portlet’s view JSP reloads. Each entity listed is a link. Click on one to view the your entity’s JSP that you made in the previous step of this tutorial.
Related assets, if you’ve created any yet, should be visible near the bottom of the page.
Most excellent! Now you know how to implement related assets in your portlets.
Another thing you might want to do is investigate permissioning in the UI. For
example, the Insults portlet only allows assets to be related by those with
UPDATE permissions. These permissions are checked in the
insult_actions.jsp, respectively. For more
information on this, see the learning path
Checking for Permissions in the UI.