Introduce ManagerDaoAdapter for create and modify

scm-webapp/src/main/java/sonia/scm/ManagerDaoAdapter.java

@@ -0,0 +1,59 @@
+package sonia.scm;
+
+import com.github.sdorra.ssp.PermissionCheck;
+import sonia.scm.util.AssertUtil;
+
+import java.util.function.Function;
+import java.util.function.Supplier;
+
+public class ManagerDaoAdapter<T extends ModelObject, E extends Exception> {
+
+  private final GenericDAO<T> dao;
+  private final Supplier<E> notFoundException;
+  private final Function<T, E> alreadyExistsException;
+
+  public ManagerDaoAdapter(GenericDAO<T> dao, Supplier<E> notFoundException, Function<T, E> alreadyExistsException) {
+    this.dao = dao;
+    this.notFoundException = notFoundException;
+    this.alreadyExistsException = alreadyExistsException;
+  }
+
+  public void modify(T object, Function<T, PermissionCheck> permissionCheck, AroundHandler<T, E> beforeUpdate, AroundHandler<T, E> afterUpdate) throws E {
+    String name = object.getId();
+
+    T notModified = dao.get(name);
+    if (notModified != null) {
+      permissionCheck.apply(notModified).check();
+      AssertUtil.assertIsValid(object);
+
+      beforeUpdate.handle(notModified);
+
+      object.setLastModified(System.currentTimeMillis());
+      object.setCreationDate(notModified.getCreationDate());
+
+      dao.modify(object);
+
+      afterUpdate.handle(notModified);
+    } else {
+      throw notFoundException.get();
+    }
+  }
+
+  public T create(T newObject, Supplier<PermissionCheck> permissionCheck, AroundHandler<T, E> beforeCreate, AroundHandler<T, E> afterCreate) throws E {
+    permissionCheck.get().check();
+    AssertUtil.assertIsValid(newObject);
+    if (dao.contains(newObject)) {
+      throw alreadyExistsException.apply(newObject);
+    }
+    newObject.setCreationDate(System.currentTimeMillis());
+    beforeCreate.handle(newObject);
+    dao.add(newObject);
+    afterCreate.handle(newObject);
+    return newObject;
+  }
+
+  @FunctionalInterface
+  public interface AroundHandler<T extends ModelObject, E extends Exception> {
+    void handle(T notModified) throws E;
+  }
+}