Oracle Application Server 10g Essentials [Electronic resources] نسخه متنی

13.1 An OracleAS Portal Page

OracleAS Portal presents information by
the page. A page in OracleAS Portal has the same
scope as a standard HTML pagea page is what a browser holds at
any one time.

In OracleAS Portal, though, pages can be assembled from many
different sources. Most importantly, a page is a part of a structural
hierarchy, as shown in Figure 13-1.

Figure 13-1. OracleAS Portal hierarchy

The top level in the hierarchy is known as an OracleAS Portal
site; it indicates a single installation of
OracleAS Portal, referenced by a specific URL prefix.

The next level in the hierarchy is a
page group. A page
group contains a group of related pages, as well as any
supporting objects required for the page group, such as styles or
page templates, which are described in subsequent sections. The
root page of a page group is typically the home
page for that group. You normally organize your OracleAS Portal sites
so that a user can remain within one page group.

Each page group contains pages, and each page can contain
subpages. A subpage can be reached from
its parent page. Whenever you copy a page with subpages, you have the
option of also copying all subpages associated with the page.
Whenever you delete a page group or page with subpages, you also
delete its subordinate pages.

A page, or a portlet within a page (we'll describe
portlets later in
this chapter), can have parameters assigned to it, and the value of a
parameter can be included in the calling URL for the page. This
capability allows you to link to a subpage or portlet while
maintaining some state information. For instance, a click on an item
may act as a link to another page with more detail about the item.
The parent page can pass the item identifier to the child page
through a parameter.

Clicking a button is an example of a particular OracleAS Portal
event. You can write code to execute in
response to an event. Event code can be implemented in JSP code, to
execute in response to user actions on the client.

13.1.1 Page Layout and Regions

Each OracleAS Portal page can contain one or more
regions, as shown in Figure 13-2.

Figure 13-2. An OracleAS Portal page, with regions highlighted

The regions in a page provide the basic layout
for the page. You can specify where a region goes on a page, in
relation to other regions, and what percent of the width or height of
a page a region occupies. A region can automatically have a banner,
as can a grouping of items within a region.

A region contains one of two types of objectseither one or
more portlets or one or more items (we'll describe
both of these later in this chapter). A region can contain tabs, each
of which brings up its own set of portlets or items. You can also
have a region automatically mark a new piece of content with an icon
for a specified time after the content is initially added to the
region.

There are two other specific types of regions:

Subpage region

This type of region automatically contains links to all the
subpages for the owning page and nothing
else. A subpage region can contain one or two levels of subpage
links.

Tab region

This type of region can't contain
anything other than objects but can be configured to include rollover
objects for information about the tab.

A page can't contain another complete page, so if
you want a page to appear within a region on another page, you have
to publish the subordinate page as a portlet, and then add that
portlet to the region.

13.1.2 Items

An item

can do any of the following:

Contain content, such as text or an image

Be a URI that points to another piece of information

Be dynamically created based on a piece of PL/SQL code

You can also create a region that uses a search to automatically add
items to the region.

An item can either point to a specific piece of content or be a way
to navigate to another location, within the OracleAS Portal framework
or outside of it. When you create an item that navigates you to
another location, you can specify whether that location should appear
within the physical boundaries of a region or in its own page or
browser instance. When you create an item, you can assign it an
expiration, which allows the item to be displayed for only a certain
length of time or prevents the item from being seen on the site at a
specific time.

Items within a region are either sorted by title or size, or simply
displayed in the order in which they were added to the region. Items
can be grouped within a region by author, date, category (which is
described later in this chapter), or item type, as well as not
grouped at all.

An item region, by default, automatically displays each item in the
page on its own row. You can specify that a region has more than one
column, which causes the items in the region to be evenly distributed
across the columns. You can also assign both the number of columns
and the number of rows. Doing so limits the display to the number of
items that can be shown in the specified columns and rows.

For convenience, OracleAS Portal enables you to load a group of items
at one time by uploading a ZIP file containing the group. Once the
file is loaded, you unzip the items, which maintain the same
directory structure they had in the ZIP file.

13.1.3 Page Appearance

As mentioned at the start of this chapter, OracleAS Portal
presents a common interface to many different sources of data. If you
had to create each individual page independently, it would be
difficult to establish a standard look and feel to your OracleAS
Portal site. OracleAS Portal has several features that give a
standard look and feel to all the pages within a site: page
templates, styles, navigation pages, shared objects, and
translations.

13.1.3.1 Page templates

A page template
assigns a standard arrangement of regions
within a page. If a page is based on a page template, the template
must contain all the regions that will be in the page. A developer or
user, with the proper privileges, has the option to not display all
the regions in a page template, but he can't add
additional regions to a page based on a template.

If you make changes to a template, the changes ripple down to all the
pages based on that template. You can remove the association between
a page and a template, which stops the propagation of template
changes to the page.

Many templates assign specific regions within a page to provide
navigation within a page group or site. For instance, there may be a
region at the top of the page that provides access to the home page
for the page group, or to a login and logout page, as well as a
region to the left of the page that provides navigation to different
parts of the page group.

For convenience, OracleAS Portal allows you to create a page template
from an existing page. A page template created in this manner
doesn't include everything in the page but does
represent the basic layout of regions in the page.

13.1.3.2 Styles

Styles define overall look-and-feel
attributes for a
page or
region. A style defines the colors and fonts used within the page or
region and can be applied to a single page, to a page group
associated with a page template, or to a region within a page.

There are style properties for items, tabs, and portlets, as well as
properties that apply to all of these groups. When a style is
changed, the changes ripple down throughout the items, tabs, and
portlets within the area controlled by the style.

When you create or modify a page, you can assign a style to the page
or have the page take on the default style of the user accessing the
page. A page template can require a particular style and not allow
any changes in it. If a page isn't based on one of
these restrictive templates, a user can select his own page style
from a list of candidate styles. A user can select a default page
style to be used when she views a particular page group or an
individual page.

If you don't assign a specific style to a page, the
page style uses a default style, either for the page group or, if
there is no default style for the page group, the style defined as
the default global style.

13.1.3.3 Navigation pages

Frequently, a page group will have a set of navigation
pages that are used throughout the group. You
can implement this functionality by creating a page with the
navigation links. These navigation pages also can contain other
prebuilt items, such as a login link; a search box; or an object map,
which lists all the page groups and pages in the site.

13.1.3.4 Shared objects

Shared objects can be used in many
pages and page templates. Typically, shared objects implement uniform
look and feel (as with color and font definitions or images) or
functionality (as with JavaScript form- and field-level validations).

13.1.3.5 Translations

OracleAS Portal can display in different
languages, as well as allow users to enter information in different
languages. You enable this capability by creating
translations for a page group. Once a
translation is created for a page group, a user can choose a language
at sign-in, or by selecting a language with the built-in Set Language
portlet. Once a user has selected a particular language, subsequent
contributions of content are kept as part of the specific translation
for the language he has selected.

The translation capability in OracleAS Portal requires manual
translation and applies only to text defined for a portal page, such
as category or perspective names or item display names.

13.1.4 Page Groups

A page group is
basically a collection of pages, along
with objects that support those pages. A page group is analogous to a
root folder in a file system. Page groups represent the highest level
in the hierarchy of OracleAS Portal organization, as shown earlier in
Figure 13-1. Each page group contains a root page,
which is the top page in the page hierarchy. A single OracleAS Portal
site can have many different root pages.

The key to creating page groups is identifying business units that
each should represent. For example, some companies create separate
page groups for each region they serve. Others create page groups for
each intranet their portal supports. Through the use of security,
page groups can be hidden from one another. Each page group has its
own security model, which can add administrative overhead to support
more page groups.

You can share objects between page groups by either creating them in
or promoting them to the Shared Objects page group. Objects
(including page templates, styles, and navigation pages) within this
group can be shared with other page groups to provide a wider scope
of reuse and standardization across an entire site.

13.1.5 Types and Attributes

When you create either a page or an
item, you
must create the object based on a
predefined object type. An object
type does several things:

Helps you to classify the information based on its characteristics

Allows you to add information, or metadata, about a particular type
of object

Enforces some basic requirements on the type

For instance, if you define a page as a URL page type, you must have
a URL indicating where the content for the page is coming from.

OracleAS Portal comes with a set of standard types, which are
associated with pages, items, and regions. You can also create your
own customized types. These customized types can inherit the
attributes of an existing page or item type. You can also include
different types of procedures to a page or item type, which
automatically adds the procedure to any page or item of that type.

The page type indicates the source of the information, such as a
standard page type for items or portlets, a URL page type for
displaying the contents of other pages on the Web, or a PL/SQL page
for displaying the results of a PL/SQL procedure. The item type
performs a similar function for items, specifying whether the item is
text, a file, an image, a link, or one of several other item types.

The type of a page or item specifies some of the attributes
associated with the object. An
attribute is essentially
metadata about the particular object, such as the name of the object
and the author of the object. As with types, OracleAS Portal comes
with a standard set of attributes, and you can also add your own
attributes.

There are two classifications of attributes:

Content attributes

These attributes are stored pieces of
information about an object. They are associated with page types and
item types.

Display attributes

These attributes can be displayed to an end
user and are associated with regions. Administrators can specify
which display attributes are actually available for a particular
region.