16 Integrating the Links Service

16.1.1 Understanding the Links Service

The Links service enables users to easily connect pieces of information, producing context between items. For example, suppose you are viewing discussion threads about a problem with a particular task. You know of a document that provides a detailed description of how to perform that task. You can link from the discussion thread to the document so that other users who view the thread can immediately view the linked document.

The Links service provides a means for the application developer to set up source objects (for example, the Discussions service) and target objects (for example, a document), thus enabling your users to create links between the two objects.

There are three actions associated with the Links service: create, delete, and manage. The manage action includes the create and delete actions.

The following custom JSF components are included in the service:

• Links Detail Button: This displays an icon and (optionally) a hyperlink that users click to open the Links Panel. To use the Links Detail Button, you must also include the Links - Dialog task flow as a region on the page.

• Links Detail Menu Item: This adds a menu item that opens the Links Panel. You can embed this item in an ADF menu. To use the Links Detail Menu Item, you must also include the Links - Dialog task flow as a region on the page.

• Links Status Icon: This has two versions:

  The gray Links icon (Figure 16-1) indicates that no links are present in the Links dialog.

  Figure 16-1 The Links Icon (No Links Present)

  
  Description of "Figure 16-1 The Links Icon (No Links Present)"
  
  

  The gold Links icon (Figure 16-2) indicates that links are present in the Links dialog.

  Figure 16-2 The Links Icon (Links Present)

  
  Description of "Figure 16-2 The Links Icon (Links Present)"
  
  

The Links service provides a way to view, access, and associate related information. For example, from an event details window you can link to the event's agenda. In a list of project assignments, you can link to the specifications relevant to each assignment.

The Links service exposes its features through a Links dialog, accessible wherever the Links icon displays in your application.

With the Links service, you can do the following:

• Link an object (such as a page) to an existing object (such as a discussion topic) by clicking the Link icon, selecting Link to Existing, choosing the resource Discussions. Optionally, you can choose a specific forum and click the topic title to choose a link (Figure 16-3).

  Figure 16-3 Links Dialog

  
  Description of "Figure 16-3 Links Dialog"
  
  

• Link an object (such as a discussion topic) to a new object (such as a new note or URL) by clicking the Link icon for discussion topic, selecting Link to New, and choosing either Note or URL.

• Create multiple links from one object.

• Delete a link.

The Links service supports bidirectional links between objects. For example, when you create a link from a discussion topic to a document, a link from the document back to the discussion topic also is created. Similarly, when you delete the link from the discussion topic to a document, the link from the document back to the discussion topic is automatically deleted. Bidirectional linking is not available for URLs, notes, and specific list rows.

For more information about the Links service at runtime, see Oracle Fusion Middleware User's Guide for Oracle WebCenter.

You can link from the following objects:

• Announcements

• Discussions

• Documents

• Events

• Lists

• Pages

• Any object to which you bind the custom JSF components, such as the Links Detail Button

You can link to the following new objects:

• Discussions

• Documents

• Events

• Notes

• URLs

You can link to the following existing objects:

• Announcements

• Discussions

• Documents

• Events

Links are not available for the following WebCenter Web 2.0 services:

• Mail

• Worklist

• Search

16.1.2 Requirements for the Links Service

Links automatically recognize any WebCenter service in your application. After you have configured a service in your application, you can add links. However, links work only on secured pages. Links icons do not appear on unsecured pages. For more information, see Section 16.2.3, "Setting Security for the Links Service."

16.2.1 Setting up Connections for the Links Service

The Links service requires a connection to the database where the WebCenter schema is installed. The link map (that is, relationship information such as what object is linked to what other object) is stored in the database.

To create the database connection:

1. In the Application Navigator, expand the Application Resources pane.

2. Right-click Connections, then click New Database.

3. Enter the following information for your database connection:

   • Connection Name: WebCenter

   • Connection Type: Oracle (JDBC)

   • Username: username

   • Password: password

   • Host: <host where you will install the WebCenter schema> (for example, localhost)

   • JDBC Port: <port> (for example, 1521)

   • SID: <system identifier for the database with the same JDBC port> (for example, ORCL)

   You must enter the Connection Name exactly as "WebCenter". There are cases when you may want to leverage an existing database connection for WebCenter services, and it may not be possible to change the database connection name to "WebCenter".

   To allow WebCenter services to use another database connection by a different name, you must add the following <data-source> tag as a child of the <wpsC:adf-service-config> element in the adf-config.xml file. (adf-service-config is a child of adf-config, and data-source is a child of adf-service-config or sibling of extension-registry-config.)

   For example:

   Example 16-1 Adding a data-source Tag in adf-config.xml

   <adf-config xmlns="http://xmlns.oracle.com/adf/config"
               xmlns:mdsC="http://xmlns.oracle.com/adf/mds/config"
               xmlns:wpsC="http://xmlns.oracle.com/webcenter/framework/service"
               xmlns:jndiC="http://xmlns.oracle.com/adf/jndi/config">
    
       <wpsC:adf-service-config xmlns="http://xmlns.oracle.com/webcenter/framework/service">
           <data-source jndi-name="java:/comp/env/jdbc/NewDatabaseConnDS"/>
      </wpsC:adf-service-config>
   </adf-config>
   

   Note:

   The syntax for jndi-name is "java:/comp/env/jdbc/NewDatabaseConnDS". This is derived from the example name NewDatabaseConn used to create the database connection in the creation wizard.

   Figure 16-4 Database Connection

   
   Description of "Figure 16-4 Database Connection"
   
   

4. Click OK.

16.2.2 Adding the Links Service at Design Time

This section explains a basic incorporation of the Links service. It contains the following subsections:

• Section 16.2.2.1, "Links Service Task Flows."

• Section 16.2.2.2, "How to Add the Links Service to your Application."

16.2.3 Setting Security for the Links Service

Links work only on secured pages. Links icons do not appear on unsecured pages. For information about configuring ADF security, see Section 3.5, "Implementing Security in Your Application."

Table 16-1 shows the permissions granted when you add Links components to a page. Task flow permissions, such as RelationshipPermission are automatically granted to authorized users when a service is consumed.

16.2.4 Troubleshooting the Links Service

This section describes common problems and solutions for the Links service.

Problem

The Links icon does not appear.

Solution

The Links service requires a database connection to the WebCenter schema, where links information is stored. Make sure that you have created the connection to the database and made it available in the Application Resources panel of the Application Navigator. If the connection is available in the Resource Palette but not in Application Resources, then simply drag the connection from the Resource Palette to the Connections folder in Application Resources.

Problem

Existing links show up, but you are not able to create new links or delete existing links.

Solution

The RelationshipPermission task flow permission is automatically granted to authorized users when a service is consumed. Verify that this permission has been granted. For information, see Section 11.1.3, "Automated Task Flow Grants."