Gumdrop JSP Examples

1. Basic JSP Example ✅ Fully Working

Demonstrates: Core JSP syntax elements including page directives, imports, declarations, scriptlets, and expressions.

Features shown:

• Page directives and import statements
• Instance variable declarations (<%! %>)
• Java scriptlets (<% %>)
• Expression evaluation (<%= %>)
• Dynamic content generation with date/time
• Session-based visit counting

What you'll learn: How Gumdrop parses JSP syntax, generates servlet code, compiles it dynamically, and executes the resulting servlet to handle requests.

1b. XML JSP Example (JSPX Format) ✅ Fully Working

Demonstrates: Same functionality as the basic JSP but using XML-compliant JSP syntax (JSPX format) to showcase Gumdrop's dual parser architecture.

Features shown:

• XML document declaration and JSP root element
• JSP directive elements (<jsp:directive.page/>)
• XML declaration elements (<jsp:declaration>)
• XML scriptlet elements (<jsp:scriptlet>)
• XML expression elements (<jsp:expression>)
• Automatic format detection and appropriate parser selection

What you'll learn: How Gumdrop's JSPParserFactory automatically detects JSP format and uses either TraditionalJSPParser or XMLJSPParser, both generating identical servlet code from different syntax formats.

2. Scripting Restrictions Demo 🚫 Intentionally Blocked

Demonstrates: JSP property group enforcement with scripting-invalid configuration that prevents Java code execution.

Features shown:

• URL pattern-based JSP property group matching (/jsp/restricted/*)
• Parse-time enforcement of scripting restrictions
• Detailed error reporting when violations occur
• Security implications of scripting controls

What you'll learn: How Gumdrop's JSP implementation enforces configuration-based restrictions during parsing, providing administrators control over script usage for security and architectural compliance.

Expected Result: JSPParseException: Scripting is disabled for this JSP page

3. Custom Taglib Support 📚 Framework Demo

Demonstrates: Taglib directive processing, TLD resolution, and custom tag recognition (requires JSTL JARs for full functionality).

Features shown:

• Taglib directive processing and prefix registration
• Tag Library Descriptor (TLD) resolution from JARs
• Custom tag recognition during parsing
• Tag handler code generation framework
• JSTL core and formatting tag examples

What you'll learn: How Gumdrop's TaglibRegistry resolves taglib URIs, parses TLD files, and generates appropriate Java code for custom tag instantiation and lifecycle management.

Note: Full JSTL functionality requires adding JSTL JAR files to WEB-INF/lib.

4. Prelude & Coda Processing ✅ Fully Working

Demonstrates: Automatic content inclusion via JSP property groups with prelude and coda configuration.

Features shown:

• Include prelude processing (automatic header insertion)
• Include coda processing (automatic footer insertion)
• Cumulative property group application
• Shared variable and method declarations
• Performance timing and request information

What you'll learn: How Gumdrop's JSPPropertyGroupResolver handles multiple property groups, applies preludes and codas cumulatively, and integrates them seamlessly into the generated servlet code.

<jsp-config>
  <!-- Basic JSP files - no restrictions -->
  <jsp-property-group>
    <url-pattern>/jsp/*.jsp</url-pattern>
    <page-encoding>UTF-8</page-encoding>
    <scripting-invalid>false</scripting-invalid>
  </jsp-property-group>

  <!-- Restricted area - scripting disabled -->
  <jsp-property-group>
    <url-pattern>/jsp/restricted/*</url-pattern>
    <scripting-invalid>true</scripting-invalid>
  </jsp-property-group>

  <!-- Enhanced area - with preludes and codas -->
  <jsp-property-group>
    <url-pattern>/jsp/enhanced/*</url-pattern>
    <include-prelude>/WEB-INF/includes/header-prelude.jsp</include-prelude>
    <include-coda>/WEB-INF/includes/footer-coda.jsp</include-coda>
  </jsp-property-group>
</jsp-config>