Re: [gradle-user] hbm2ddl within a Gradle task on a JPA annotated Spring application

[Silvio Wangler]

Well I took some time off that problem but I was able to solve it recently.

<code name="build.gradle">
import org.hibernate.tool.hbm2ddl.SchemaExport

buildscript {
    repositories {
        mavenCentral()
        maven {
            url 'https://repository.jboss.org/nexus/content/groups/public'
            url 'http://repo.springsource.org/libs-milestone'
        }
    }
    dependencies {
        classpath group: 'org.hibernate', name: 'hibernate-core', version:
ext.hibernateVersion,
"org.hibernate:hibernate-entitymanager:${ext.hibernateVersion}",
'com.h2database:h2:1.3.166'
        classpath('org.springframework.data:spring-data-jpa:1.1.0.RC1') {
            exclude group: 'org.slf4j', module: 'jcl-over-slf4j'
        }
    }
}

task ddl(type: HibernateJpaSchemaGenerationTask, dependsOn: [compileJava,
processResources])
jar.dependsOn << ddl


class HibernateJpaSchemaGenerationTask extends DefaultTask {

    def Map<String, String> dialects = [ORACLE:
"org.hibernate.dialect.Oracle10gDialect", MYSQL:
"org.hibernate.dialect.MySQLDialect", MYSQL5:
"org.hibernate.dialect.MySQL5Dialect", MYSQL5INNODB:
"org.hibernate.dialect.MySQL5InnoDBDialect", HSQL:
"org.hibernate.dialect.HSQLDialect", H2: "org.hibernate.dialect.H2Dialect"]

    def source = project.sourceSets.main.output.classesDir
    def target = project.sourceSets.main.output.resourcesDir

    @TaskAction
    def performSchemaGeneration() {

        assert source.isDirectory()
        assert target.isDirectory()

        URLClassLoader loader = new URLClassLoader(source.toURI().toURL()
as URL[], getClass().getClassLoader())

        def clazzez = []
        source.eachFileRecurse { file ->
            if (file.name.endsWith('.class')) {
                def classRelPath = file.absolutePath - source.absolutePath
                clazzez <<
classRelPath[1..-7].replace(System.properties['file.separator'], '.')
            }
        }

        org.hibernate.cfg.Configuration cfg = new
org.hibernate.cfg.Configuration()
        cfg.properties['hibernate.hbm2ddl.auto'] = 'create'

        clazzez.each { clazz ->

            try {
                println "Trying to load class ${clazz}"
                Class possibleJpaEntity = Class.forName(clazz, true, loader)
                println "Class ${clazz} sucessfully loaded"

                if
(possibleJpaEntity.isAnnotationPresent(javax.persistence.Entity.class)) {
                    cfg.addAnnotatedClass(possibleJpaEntity)
                } else {
                    println("Ignoring class
${possibleJpaEntity.getCanonicalName()} since it has no
javax.persistence.Entity annotation present")
                }

            } catch (Exception e) {
                println e
            }
        }

        ClassLoader prev = Thread.currentThread().getContextClassLoader()
        try {
            // Need to set our class loader to the current thread
            Thread.currentThread().setContextClassLoader(loader)
            dialects.each { key, value ->
                final file = new File(target,
"ddl_${key.toLowerCase()}.sql")

                println "Writing to ${file.absolutePath}"

                cfg.setProperty("hibernate.dialect", value)

                SchemaExport export = new
org.hibernate.tool.hbm2ddl.SchemaExport(cfg)
                export.delimiter = ';'
                export.outputFile = file.absolutePath
                export.execute true, false, false, false
            }
        } finally {
            Thread.currentThread().setContextClassLoader(prev)
        }
    }
}
</code>