Content assist helps you insert or finish a tag or function or
finish a line of code in a structured text editor. The placement of the cursor
in the source file provides the context for the content assist to offer suggestions
for completion.
The sections below describe specifics of HTML content assist, JavaScript™ content
assist, and JSP content assist.
HTML content assist
HTML is flexible in that some
HTML elements allow end tags to be optionally omitted, such as P, DT, DD, LI, THEAD, TR, TD, TH,
and so on. Other HTML elements that are defined to have no content may require
the end tag always be omitted, such as BR, HR, LINK, META,
and IMG. This flexibility makes the content assist function
within the HTML source page editor less precise than it might be with a more
rigidly constrained markup language.
HTML content assist is most beneficial
when you need to complete a tag name, add an attribute name-value pair within
a start tag, or select from an enumerated list of attribute values.
Although
content assist only shows attribute names that have not already been specified
in a start tag, it does not take into account grammar constraints for tags.
For example, the HEAD element in HTML only permits zero or
one occurrences of a TITLE tag in its content. If you prompt
for content assist within a HEAD content that already contains
a TITLE tag, content assist will still show TITLE in
its proposal list.
However, if an attribute is required according to
the DTD/Schema, that attribute will show up at the top of the list, with a
yellow circle indicator on its icon.
If your cursor is in a position
where content assist is available, a pop-up list of available choices is displayed.
The list is based on the context. For example, if you use content assist directly
after an opening paragraph tag (<p>) , the first item
in the content assist list will be the corresponding closing paragraph (</p>)
tag.
The content assist list displays all available tags for the current
cursor position, including templates. The picture below shows the default
content assist list for a paragraph tag example:
Tag proposals
are listed alphabetically. If you type a < (to begin a
new tag) before prompting for content assist, and begin typing the first one
or two letters of the tag that you want to add, the proposal list automatically
refreshes to reflect proposals that match the pattern you have typed. If you
do not type a < before prompting for content assist, you
can click within the proposal list and then type the letter that the tag begins
with, to reduce (somewhat) the amount of scrolling to locate the desired tag.
As
you type the first one or two letters of the attribute names or enumerated
attribute values that you want to add to a tag, the list automatically refreshes
to reflect proposals that match the pattern you have typed.
Restriction: 
When using Linux (Motif
or GTK) and a DBCS locale, double-clicking on the content assist list can
sometimes cause the Java™ VM to terminate. Instead of double-clicking
on the list, use the arrows and Enter keys to make the selection from the
list.
JSP content assist
You have many options for embedding Java and
HTML code in your JSP pages by using content assist.
All of the JSP
tags are included both in the template list and in XML format (for example, <jsp:expression>).
To add JSP scriptlet tags, for example, move the cursor to the appropriate
position in the file and press Ctrl+Space to use content assist. Select 
from the proposal list to insert <% %> in the
document.
Scriptlets are inserted in a tag
<% %>.
For example:
<% System.currentTimeMillis() %>
This
example will evaluate the Java statement to get the current time in
milliseconds.
To have the result of the statement inserted in the file,
put an equals sign (=) in the front of the statement. For example:
<b>This is the time : <%= System.currentTimeMillis()%></b>
When you are within a scriptlet you are writing pure Java code.
Therefore, content assist works exactly the same as it does for the Java editor.
For example, if you request content assist after
System,
content assist displays a list of methods.
Note: Java content assist works only in a Web
project, because it requires a buildpath to find the appropriate Java classes.
There
are also special tags such as useBean. For example:
<jsp:useBean id="useBean" class="java.lang.String"/>
The
useBean tag enables you to create a bean called aString of
type String. Then when you use content assist, this is recognized
as a declared variable. For example, if you use content assist after aString,
as follows:
<% aString. %>
the content assist
list shows available methods. This is because
aString has
been declared as a bean of type String.
If you use content assist after
the
a, as follows:
<% a %>
content
assist knows that
aString exists, and it is shown in the
content assist list.
