Accessing Data in XML Form

For the photograph widget, the source value is no longer a simple string, instead it is an XML document. The approach that is used for the email address widget needs to be extended to allow values that are embedded in the XML document to be retrieved individually. Support is provided for accessing data in an XML by extending the source path. The code to retrieve the person's name and unique identifier from the XML document is shown here.

An EMail Address Widget described how to access a single source value by using a Field object, its Binding property, and a source path.

String personID = context.getDataAccessor()
      .get(component.getBinding()
          .getSourcePath().extendPath("photo/id"));
    String personName = context.getDataAccessor()
        .get(component.getBinding()
            .getSourcePath().extendPath("photo/name"));

The source path is retrieved from the field's binding in the same way as the email address widget in the previous section. However, the source path is not passed directly to the get method of the data accessor that is retrieved from the context. Doing this would return the entire XML document as a string. Instead, the source path is first extended by using the extendPath method. The path extensions are photo/id and photo/name. They correspond directly to the tree structure of the XML document. For example, the photo/id path means that the data accessor retrieves the body content of the id element, which is a child of the photo element. In the sample XML above, this is the value "101". Those familiar with XPATH might recognize the format of these paths. However, while the extended paths used here are similar, they are not XPATH. Creating simple XML documents where each value is represented in the body content of an element means that the path formats shown in the section are all that is required to use in a widget. However, the Extending Paths for XML Data Access section describes XML data access through path extension in full detail.