Expressions
An expression specifies an arbitrary Java expression.
Standalone Task Use
The task compiler generates Java source code that evaluates the Java expression and then embeds the results within the task at the point where the expression resides in the task.
 |
In tasks, expressions can only be placed within the attributes of the param tag. Where previously only the data attribute could contain an expression, now all attributes can be used, including the following: name, data, delim, default, valueSeparator, and elementSeparator.
|
JSP Use
The expression is evaluated and its result is displayed at the point in the JSP page where the tag is defined.
|
|
The use of expressions within Info*Engine custom param tag attribute values may not give you the results you expect when you are using the Tomcat servlet engine. In the Tomcat servlet engine, when an expression is embedded within a data attribute value, it is not evaluated correctly. However, if the entire value for the data attribute is an expression, the result is correct.
To work around this issue, you can create the entire value in a scriptlet, and then use the results in an expression in the data attribute. For example, the following data attribute on a param tag is not evaluated correctly:
<ie:param name="ELEMENT" data="ENAME=<%=ENAME%>"/>
Instead, you can code this as follows:
<% String elValue = "ENAME=" + ENAME; %>
<ie:param name="ELEMENT" data="<%=elValue%>"/> |
Tag Syntax
<%= expression %>
Example
In the following paragraph, two expressions are used to insert the Java variables table and where:
<p><b>
Query table <%= table%> with where clause <%= where%>.
</b></p>
Query table <%= table%> with where clause <%= where%>.
</b></p>