diff -r 4f912cd42876 -r 86b5d8a1662f src/main/kotlin/de/uapcore/lightpit/dao/AbstractIssueDao.kt
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/kotlin/de/uapcore/lightpit/dao/AbstractIssueDao.kt	Thu Nov 19 13:58:54 2020 +0100
@@ -0,0 +1,99 @@
+/*
+ * Copyright 2020 Mike Becker. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package de.uapcore.lightpit.dao
+
+import de.uapcore.lightpit.entities.*
+import java.sql.SQLException
+
+abstract class AbstractIssueDao : AbstractChildEntityDao<Issue, Project>() {
+
+    /**
+     * Lists all issues that are related to the specified component and version.
+     * If component or version is null, search for issues that are not assigned to any
+     * component or version, respectively.
+     *
+     * @param project the project
+     * @param component the component
+     * @param version the version
+     * @return a list of issues
+     */
+    abstract fun list(project: Project, component: Component?, version: Version?): List<Issue>
+
+    /**
+     * Lists all issues that are related to the specified version.
+     * If the version is null, lists issues that are not assigned to any version.
+     *
+     * @param project the project
+     * @param version the version or null
+     * @return a list of issues
+     */
+    abstract fun list(project: Project, version: Version?): List<Issue>
+
+    /**
+     * Lists all issues that are related to the specified component.
+     * If the component is null, lists issues that are not assigned to a component.
+     *
+     * @param project the project
+     * @param component the component or null
+     * @return a list of issues
+     */
+    abstract fun list(project: Project, component: Component?): List<Issue>
+
+    /**
+     * Lists all comments for a specific issue in chronological order.
+     *
+     * @param issue the issue
+     * @return the list of comments
+     */
+    abstract fun listComments(issue: Issue): List<IssueComment>
+
+    /**
+     * Stores the specified comment in database.
+     * This is an update-or-insert operation.
+     *
+     * @param issue the issue to save the comment for
+     * @param comment the comment to save
+     */
+    abstract fun saveComment(issue: Issue, comment: IssueComment)
+
+    /**
+     * Saves an instances to the database.
+     * Implementations of this DAO must guarantee that the generated ID is stored in the instance.
+     *
+     * @param instance the instance to insert
+     * @param parent the parent project
+     * @throws SQLException on any kind of SQL error
+     */
+    abstract override fun save(instance: Issue, parent: Project)
+
+    /**
+     * Retrieves the affected, scheduled and resolved versions for the specified issue.
+     *
+     * @param issue the issue to join the information for
+     */
+    abstract fun joinVersionInformation(issue: Issue)
+}
\ No newline at end of file