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# Language Module
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The JSP Language Module registers JSP as a supported language in the PMD framework and provides configuration for file extensions and copy-paste detection capabilities.
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## Language Registration
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### JspLanguageModule
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Main class that registers JSP language with PMD framework.
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```java { .api }
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public class JspLanguageModule extends SimpleLanguageModuleBase implements CpdCapableLanguage {
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    public JspLanguageModule();
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    public static JspLanguageModule getInstance();
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    public CpdLexer createCpdLexer(LanguagePropertyBundle bundle);
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}
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```
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**Usage:**
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```java
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import net.sourceforge.pmd.lang.jsp.JspLanguageModule;
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import net.sourceforge.pmd.lang.LanguageRegistry;
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// Get the JSP language module instance
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JspLanguageModule jspModule = JspLanguageModule.getInstance();
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// Or get via language registry
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JspLanguageModule module = (JspLanguageModule) LanguageRegistry.PMD.getLanguageById("jsp");
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```
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**Methods:**
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- `getInstance()`: Returns the singleton instance of the JSP language module
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- `createCpdLexer(LanguagePropertyBundle)`: Creates a lexer for copy-paste detection
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**File Extensions:**
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- `.jsp`: JavaServer Pages
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- `.jspx`: JSP XML format
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- `.jspf`: JSP fragment files  
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- `.tag`: JSP tag files
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**Language Versions:**
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- Version 2: Legacy JSP
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- Version 3: Default version (modern JSP)
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### JspHandler
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Language version handler that provides parser instances.
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```java { .api }
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public class JspHandler extends AbstractPmdLanguageVersionHandler {
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    public Parser getParser();
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}
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```
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**Usage:**
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```java
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import net.sourceforge.pmd.lang.jsp.JspHandler;
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import net.sourceforge.pmd.lang.jsp.ast.JspParser;
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JspHandler handler = new JspHandler();
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Parser parser = handler.getParser(); // Returns JspParser instance
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```
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**Methods:**
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- `getParser()`: Returns a new `JspParser` instance for parsing JSP files
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## Service Registration
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The language module is automatically registered with PMD through the service loader mechanism:
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**File:** `/META-INF/services/net.sourceforge.pmd.lang.Language`
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```
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net.sourceforge.pmd.lang.jsp.JspLanguageModule
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```
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This enables PMD to automatically discover and load the JSP language support when the module is on the classpath.
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## Integration with PMD Framework
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The JSP language module integrates with PMD's core framework:
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1. **Language Registry**: Automatically registers JSP language with ID "jsp"
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2. **File Processing**: Associates JSP file extensions with the language
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3. **Parser Integration**: Provides JSP parser through the handler
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4. **CPD Integration**: Enables copy-paste detection for JSP files
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5. **Rule Processing**: Enables JSP-specific rules to be applied to JSP files
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## Examples
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### Basic Language Module Usage
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```java
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import net.sourceforge.pmd.lang.jsp.JspLanguageModule;
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import net.sourceforge.pmd.cpd.CpdLexer;
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import net.sourceforge.pmd.lang.LanguagePropertyBundle;
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// Get language module
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JspLanguageModule module = JspLanguageModule.getInstance();
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// Create CPD lexer for duplicate detection
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LanguagePropertyBundle bundle = // ... PMD configuration
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CpdLexer lexer = module.createCpdLexer(bundle);
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```
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### Programmatic Integration
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```java
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import net.sourceforge.pmd.lang.LanguageRegistry;
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import net.sourceforge.pmd.lang.Language;
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// Check if JSP language is available
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Language jspLang = LanguageRegistry.PMD.getLanguageById("jsp");
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if (jspLang != null) {
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    System.out.println("JSP language supported");
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    System.out.println("Extensions: " + jspLang.getExtensions());
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}
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```
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The language module provides the foundation for all JSP analysis capabilities in PMD, enabling the framework to recognize JSP files and route them to the appropriate parser and rules.