Maven plugin

The plugin reads JFlex grammar specification files (.jflex) and generates a corresponding Java parser (in target/generated-source/jflex by default).

Usage

Minimal configuration

This configuration generates java code of a parser for all grammar files (*.jflex, *.jlex, *.lex, *.flex) found in src/main/jflex/ and its sub-directories.

The name and package of the generated Java source code are the ones defined in the grammar. The generated Java source code is placed in target/generated-source/jflex, in sub-directories following the Java convention on package names.

Update the pom.xml to add the plugin:

<project>
  <!-- ... -->
  <build>
    <plugins>
      <plugin>
        <groupId>de.jflex</groupId>
        <artifactId>jflex-maven-plugin</artifactId>
        <version>${project.version}</version>
        <executions>
          <execution>
            <goals>
              <goal>generate</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
    <!-- ... -->
  </build>
  <!-- ... -->
</project>

More complex configuration

This example generates the source for the two grammars src/main/lex/preprocessor.jflex and /pub/postprocessor.jflex, as well as all grammar files found in src/main/jflex (and its sub-directories). The generated Java code is placed into src/main/java instead of target/generated-sources/jflex.

      <plugin>
        <groupId>de.jflex</groupId>
        <artifactId>jflex-maven-plugin</artifactId>
        <version>${project.version}</version>
        <executions>
          <execution>
            <goals>
              <goal>generate</goal>
            </goals>
            <configuration>
              <outputDirectory>src/main/java</outputDirectory>
              <lexDefinitions>
                <lexDefinition>src/main/jflex</lexDefinition>
                <lexDefinition>src/main/lex/preprocessor.jflex</lexDefinition>
                <lexDefinition>/pub/postprocessor.jflex</lexDefinition>
              </lexDefinitions>
            </configuration>
          </execution>
        </executions>
      </plugin>

Even more complex configuration, using several executions

This generates the source for

  • all files found in src/main/lex/, using strict JLex compatibility.

  • and all files found in src/main/jflex, in verbose mode.

      <plugin>
        <groupId>de.jflex</groupId>
        <artifactId>jflex-maven-plugin</artifactId>
        <version>${project.version}</version>
        <executions>
          <execution>
            <id>strict jlex</id>
            <goals>
              <goal>generate</goal>
            </goals>
            <configuration>
              <lexDefinitions>
                <lexDefinition>src/main/lex</lexDefinition>
              </lexDefinitions>
              <jlex>true</jlex>
            </configuration>
          </execution>
          <execution>
            <id>jflex</id>
            <goals>
              <goal>generate</goal>
            </goals>
            <configuration>
              <lexDefinitions>
                <lexDefinition>src/main/jflex</lexDefinition>
              </lexDefinitions>
              <verbose>true</verbose>
            </configuration>
          </execution>
        </executions>
      </plugin>

More information