Updated after second round of review comments

- Move the artifactDAO from flowDAO. This will make code "clean" and
    @maheshkelkar happy
  - Fixes #163

src/main/groovy/deploydb/ModelCleanupTask.groovy

@@ -2,6 +2,7 @@ package deploydb
 
 import com.codahale.metrics.annotation.Timed
 import com.google.common.collect.ImmutableMultimap
+import deploydb.models.Artifact
 import io.dropwizard.servlets.tasks.Task
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
@@ -33,7 +34,14 @@ class ModelCleanupTask extends Task {
 
         this.workFlow.deployDBApp.withHibernateSession() {
             try {
-                this.workFlow.flowDAO.deleteFlowByArtifactNameGroupVersion(group, name, version)
+                // Lets fetch the artifact using name, group and version
+                Artifact artifact = this.workFlow.artifactDAO.findArtifactByGroupNameVersion(
+                        group, name,version)
+                if(artifact == null) {
+                    return
+                }
+                // Now delete flow using the artifact id
+                this.workFlow.flowDAO.deleteFlowByArtifactId(artifact.id)
                 output.println("Done!")
             } catch (Exception e) {
                 logger.error("Cleanup of the model failed with an exception: ", e)

src/main/groovy/deploydb/dao/ArtifactDAO.groovy

@@ -69,9 +69,27 @@ class ArtifactDAO extends AbstractDAO<Artifact> {
         return artifacts
     }
 
-    boolean artifactExists(String group, String name, String version) {
+    /**
+     * Fetch the artifact using group, name, version
+     * @param group Artifact group
+     * @param name Artifact name
+     * @param version Artifact version
+     * @return Artifact returned by the search if available otherwise null
+     */
+    Artifact findArtifactByGroupNameVersion(String group, String name, String version) {
         return criteria().add(Restrictions.eq('group', group))
-                  .add(Restrictions.eq('name', name))
-                  .add(Restrictions.eq('version', version)).uniqueResult() == null ? false: true
+                .add(Restrictions.eq('name', name))
+                .add(Restrictions.eq('version', version)).uniqueResult()
+    }
+
+    /**
+     * Check if the artifact exists based group, name, version
+     * @param group Artifact group
+     * @param name Artifact name
+     * @param version Artifact version
+     * @return true if Artifact exists otherwise false
+     */
+    boolean artifactExists(String group, String name, String version) {
+        return findArtifactByGroupNameVersion(group, name, version) == null ? false: true
     }
 }

src/main/groovy/deploydb/dao/FlowDAO.groovy

@@ -1,6 +1,5 @@
 package deploydb.dao
 
-import deploydb.models.Artifact
 import deploydb.models.Flow
 import groovy.transform.InheritConstructors
 import io.dropwizard.hibernate.AbstractDAO
@@ -13,20 +12,14 @@ import org.hibernate.criterion.Restrictions
 @InheritConstructors
 class FlowDAO extends AbstractDAO<Flow> {
 
-    void deleteFlowByArtifactNameGroupVersion(String group,
-                                              String name,
-                                              String version) {
+    /**
+     * Delete the flow based on Artifact id. This function will delete the assocaited models -
+     * Artifact, Deployments and PromotionResults
+     * @param id Artifact id of the flow
+     */
+    void deleteFlowByArtifactId(long id) {
         Session session = currentSession()
-
-        // We can't find the flow using artifact name, group and version, so
-        // we need to fetch the artifact, and use artifact id to fetch the flow
-        ArtifactDAO artifactDAO = new ArtifactDAO(currentSession().getSessionFactory())
-        Artifact artifact = artifactDAO.criteria().add(Restrictions.eq('group', group))
-                .add(Restrictions.eq('name', name)).add(Restrictions.eq('version', version)).uniqueResult()
-        if(artifact == null) {
-            return
-        }
-        Flow flow = criteria().add(Restrictions.eq('artifact.id', artifact.id)).uniqueResult()
+        Flow flow = criteria().add(Restrictions.eq('artifact.id', id)).uniqueResult()
 
         // now delete the found flow
         session.delete(flow)

src/test/groovy/deploydb/models/FlowSpec.groovy

@@ -3,6 +3,7 @@ package deploydb.models
 import deploydb.IntegrationTestAppHelper
 import deploydb.Status
 import deploydb.dao.PromotionResultDAO
+import spock.lang.Ignore
 import spock.lang.Specification
 import dropwizardintegtest.IntegrationModelHelper
 import dropwizardintegtest.IntegrationRestApiClient
@@ -333,8 +334,10 @@ class FlowCleanupSpec extends Specification {
 
         // remove the flow
         integAppHelper.runner.getApplication().withHibernateSession {
+            Artifact artifact = integAppHelper.runner.getApplication().workFlow.artifactDAO.
+                    findArtifactByGroupNameVersion("basic.group.1", "bg1", "1.2.345")
             integAppHelper.runner.getApplication().workFlow.flowDAO.
-                    deleteFlowByArtifactNameGroupVersion("basic.group.1", "bg1", "1.2.345")
+                    deleteFlowByArtifactId(artifact.id)
         }