cgen is a maven-cayenne-plugin goal that generates and maintains source (.java) files of persistent objects based on a DataMap. By default, it is bound to the generate-sources phase. If "makePairs" is set to "true" (which is the recommended default), this task will generate a pair of classes (superclass/subclass) for each ObjEntity in the DataMap. Superclasses should not be changed manually, since they are always overwritten. Subclasses are never overwritten and may be later customized by the user. If "makePairs" is set to "false", a single class will be generated for each ObjEntity.

By creating custom templates, you can use cgen to generate other output (such as web pages, reports, specialized code templates) based on DataMap information.

Example - a typical class generation scenario, where pairs of classes are generated, and superclasses are placed in a separate package:

<plugin>
    <groupId>org.apache.cayenne.plugins</groupId>
    <artifactId>maven-cayenne-plugin</artifactId>
    <version>X.Y.Z</version>

    <!--
    There's an intermittent problem when using Maven/cgen in Eclipse with  m2eclipse plugin that
    requires placing "configuration" section at the plugin level, instead of execution
    level.
    -->
    <configuration>
        <map>${project.basedir}/src/main/resources/my.map.xml</map>
        <destDir>${project.basedir}/src/main/java</destDir>
        <superPkg>org.example.model.auto</superPkg>
    </configuration>

    <executions>
        <execution>
            <goals>
                <goal>cgen</goal>
            </goals>
        </execution>
    </executions>
</plugin>

cdbgen is a maven-cayenne-plugin goal that drops and/or generates tables in a database on Cayenne DataMap. By default, it is bound to the pre-integration-test phase.

Example - creating a DB schema on a local HSQLDB database:

<plugin>
    <groupId>org.apache.cayenne.plugins</groupId>
    <artifactId>maven-cayenne-plugin</artifactId>
    <version>X.Y.Z</version>
    <executions>
        <execution>
            <configuration>
                <map>${project.basedir}/src/main/resources/my.map.xml</map>
                <url>jdbc:hsqldb:hsql://localhost/testdb</url>
                <adapter>org.apache.cayenne.dba.hsqldb.HSQLDBAdapter</adapter>
                <driver>org.hsqldb.jdbcDriver</driver>
                <username>sa</username>
            </configuration>
            <goals>
                <goal>cdbgen</goal>
            </goals>
        </execution>
    </executions>
</plugin>

cdbimport is a maven-cayenne-plugin goal that generates a DataMap based on an existing database schema. By default, it is bound to the generate-sources phase. This allows you to generate your DataMap prior to building your project, possibly followed by "cgen" execution to generate the classes.

Example - loading a DB schema from a local HSQLDB database (essentially a reverse operation compared to the cdbgen example above) :

<plugin>
    <groupId>org.apache.cayenne.plugins</groupId>
    <artifactId>maven-cayenne-plugin</artifactId>
    <version>X.Y.Z</version>

    <executions>
        <execution>
            <configuration>
                <map>${project.basedir}/src/main/resources/my.map.xml</map>
                <url>jdbc:mysql://127.0.0.1/mydb</url>
                <driver>com.mysql.jdbc.Driver</driver>                        
                <username>sa</username>
                <defaultPackage>com.example.cayenne</defaultPackage>
            </configuration>
            <goals>
                <goal>cdbimport</goal>
            </goals>
        </execution>
    </executions>
</plugin>

This is an Ant counterpart of "cdbimport" goal of maven-cayenne-plugin described above. It has exactly the same properties. Here is a usage example:

 <cdbimport map="${context.dir}/WEB-INF/my.map.xml"
    driver="com.mysql.jdbc.Driver" 
    url="jdbc:mysql://127.0.0.1/mydb" 
    username="sa"
    defaultPackage="com.example.cayenne"/>