cgen is a cayenne-maven-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 with default Maven source destination and superclass package:

<plugin>
    <groupId>org.apache.cayenne.plugins</groupId>
    <artifactId>cayenne-maven-plugin</artifactId>
    <version>4.0.B2</version>

    <configuration>
        <map>${project.basedir}/src/main/resources/my.map.xml</map>
    </configuration>

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

cdbgen is a cayenne-maven-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>cayenne-maven-plugin</artifactId>
    <version>4.0.B2</version>
    <executions>
        <execution>
            <configuration>
                <map>${project.basedir}/src/main/resources/my.map.xml</map>
                <adapter>org.apache.cayenne.dba.hsqldb.HSQLDBAdapter</adapter>
                <dataSource>
                    <url>jdbc:hsqldb:hsql://localhost/testdb</url>
                    <driver>org.hsqldb.jdbcDriver</driver>
                    <username>sa</username>
                </dataSource>
            </configuration>
            <goals>
                <goal>cdbgen</goal>
            </goals>
        </execution>
    </executions>
</plugin>

cdbimport is a cayenne-maven-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. CDBImport plugin described in details in chapter "DB-First Flow"

<!-- Strip prefix -->
<stripFromTableNames>^myt_</stripFromTableNames>

<!-- Strip suffix -->
<stripFromTableNames>_s$</stripFromTableNames>

<!-- Strip multiple occurrences in the middle -->
<stripFromTableNames>_abc</stripFromTableNames>

<dbimport>
	<catalog name="test_catalog">
		<schema name="test_schema">
			<includeTable>.*</includeTable>
			<excludeTable>test_table</excludeTable>
		</schema>
	</catalog>

	<includeProcedure pattern=".*"/>
</dbimport>

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>cayenne-maven-plugin</artifactId>
    <version>4.0.B2</version>

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

Cayenne Gradle plugin provides several tasks, such as synching generated Java classes with the mapping or synching mapping with the database. Plugin aslo provides cayenne extension that have some useful utility methods. Here is example of how to include Cayenne plugin into your project:

buildscript {
    // add Maven Central repository
    repositories {
        mavenCentral()
    }
    // add Cayenne Gradle Plugin
    dependencies {
        classpath group: 'org.apache.cayenne.plugins', name: 'cayenne-gradle-plugin', version: '4.0.B2'
    }
}

// apply plugin
apply plugin: 'org.apache.cayenne'

// set default DataMap
cayenne.defaultDataMap 'datamap.map.xml'

// add Cayenne dependencies to your project
dependencies {
    // this is a shortcut for 'org.apache.cayenne:cayenne-server:VERSION_OF_PLUGIN'
    compile cayenne.dependency('server')
    compile cayenne.dependency('java8')
}

cgen {
    client = false
    mode = 'all'
    overwrite = true
    createPropertiesNames = true
}

task clientCgen(type: cayenne.cgen) {
    client = true
}

cdbimport {
    // map can be skipped if it is defined in cayenne.defaultDataMap
    map 'datamap.map.xml'

    dataSource {
        driver 'com.mysql.cj.jdbc.Driver'
        url 'jdbc:mysql://127.0.0.1:3306/test?useSSL=false'
        username 'root'
        password ''
    }

    dbImport
        // additional settings
        usePrimitives false
        defaultPackage 'org.apache.cayenne.test'

        // DB filter configuration
        catalog 'catalog-1'
        schema 'schema-1'

        catalog {
            name 'catalog-2'

            includeTable 'table0', {
                excludeColumns '_column_'
            }

            includeTables 'table1', 'table2', 'table3'

            includeTable 'table4', {
                includeColumns 'id', 'type', 'data'
            }

            excludeTable '^GENERATED_.*'
        }

        catalog {
            name 'catalog-3'
            schema {
                name 'schema-2'
                includeTable 'test_table'
                includeTable 'test_table2', {
                    excludeColumn '__excluded'
                }
            }
        }

        includeProcedure 'procedure_test_1'

        includeColumns 'id', 'version'

        tableTypes 'TABLE', 'VIEW'
    }
}

cdbgen {

    adapter 'org.apache.cayenne.dba.derby.DerbyAdapter'

    dataSource {
        driver 'org.apache.derby.jdbc.EmbeddedDriver'
        url 'jdbc:derby:build/testdb;create=true'
        username 'sa'
        password ''
    }

    dropTables true
    dropPk true

    createTables true
    createPk true
    createFk true
}

cgen.dependsOn cdbimport
compileJava.dependsOn cgen

This is an Ant counterpart of "cdbimport" goal of cayenne-maven-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"/>