Expression Language 3.0 is in public review

The Expression Language (EL) is widely used in JSP and JSF. With version 3 the EL now becomes an independent specification. The EL v3 (JSR 314) is in public review until the end of July. It will be released in sync with Java EE 7 (Update: EL 3.0 was released in may 2013). New features include:

•  As an independent specification, EL now comes with a standalone API, allowing usage outside a web container.
  
• You can write your own ELProcessor. The source code is available, but I wish they had put the javadoc for  browsing at the project site as well.
• Java 8 stuff
• Lambda expressions
• Collection literals follow proposed Java 8 syntax
• List: [1, "two", 3.0]
• Set: {1, 2, 3}
• Map: {"one":1, "two":2, "three":3}
• Collection streaming
• Assignment operator (=) for changing values:
• ${customer.name = 'Jan'}
• String concatenation: + or cat operator
• ${‘Welcome ‘ += customer.name += ‘ to our site’}.
• Support for static references using the T construct (Type). 
• By default only java.* and javax.* packages are available, but you can modify this using the EL API.
  
• ${T(java.util.Calendar).APRIL}
• ${T(java.util.Calendar).getInstance()}
•  You can call constructors as a static method without a name. To call the default Calendar constructor:
  
• ${T(java.util.Calendar).()}
• For java.lang you can use the class without using the T construct
• ${Boolean.TRUE}

JSTL/JSP EL alternate Struts excercise solution

The De Post/PMC excercises (and the Struts blank sample application) are based on

• Struts
  • tags-bean
  • tags-logic
  • tags-html
• JSP scriptlets

In this post we will show how to move this to

• Struts
  • tags-html
• JSTL
• JSP expression language

To enable JSTL/JSP/EL support in your application follow these instructions. Here’s the table from the excercise rendered with JSTL/JSP EL:

<c:forEach  var="product" items="${List}"  varStatus ="status">
  <tr class="${(status.index%2==1)?'odd':'even'}">
    <td>
      <html:link action="<%=modify%>" paramId="id" paramName="product" paramProperty="id">
        <html:img srcKey="icon.edit" altKey="icon.alt.edit" border="0"/>
      </html:link> 
    </td> 
    <td>
      <html:link action="<%=remove %>" paramId="id" paramName="product" paramProperty="id">
        <html:img srcKey="icon.trash" altKey="icon.alt.trash" border="0"/>
      </html:link>
    </td>
    <td> ${product.name}</td> 
    <td> ${product.description}</td>
  </tr>
</c:forEach>