Introduce few abstract classes/traits: FileType, File and Database.

These abstract interfaces will provide all functionality needed by Gimd
to access actual datastore. Canonical implementation of these interfaces
will be provided on top of JGit.

Signed-off-by: Grzegorz Kossakowski <grek@google.com>

4 files changed, 119 insertions, 0 deletions

diff --git a/src/main/scala/com/google/gimd/Database.scala b/src/main/scala/com/google/gimd/Database.scala
new file mode 100644
index 0000000..668bdd2
--- /dev/null
+++ b/src/main/scala/com/google/gimd/Database.scala
@@ -0,0 +1,30 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd
+
+import file.{File, FileType}
+
+/**
+ * Trait that provides all functionality for Gimd to ask specific storage implementation
+ * for needed data in an efficient way.
+ */
+trait Database {
+
+  /**
+   * @return iterator over collection of all Files that conform to passed FileType[T].
+   */
+  def all[T](fileType: FileType[T]): Iterator[File[T]]
+
+}
diff --git a/src/main/scala/com/google/gimd/DatabaseException.scala b/src/main/scala/com/google/gimd/DatabaseException.scala
new file mode 100644
index 0000000..d47ac31
--- /dev/null
+++ b/src/main/scala/com/google/gimd/DatabaseException.scala
@@ -0,0 +1,18 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd
+
+abstract class DatabaseException(message: String, cause: Throwable)
+        extends Exception(message, cause)
diff --git a/src/main/scala/com/google/gimd/file/File.scala b/src/main/scala/com/google/gimd/file/File.scala
new file mode 100644
index 0000000..4ac695e
--- /dev/null
+++ b/src/main/scala/com/google/gimd/file/File.scala
@@ -0,0 +1,33 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd.file
+
+/**
+ * File is one of the fundamental concepts in Gimd. Basically File is unit of
+ * storage with path associated with it.
+ *
+ * Every file has exactly one FileType[T] associated and conforms to meta-data
+ * carried by FileType[T].
+ *
+ * As consequence of association to FileType[T] single File[T] stores single message
+ * which is representation of type T.
+ */
+trait File[T] {
+  val path: String
+  val fileType: FileType[T]
+  val message: Message
+  val userObject: T
+
+}
diff --git a/src/main/scala/com/google/gimd/file/FileType.scala b/src/main/scala/com/google/gimd/file/FileType.scala
new file mode 100644
index 0000000..4ca2db1
--- /dev/null
+++ b/src/main/scala/com/google/gimd/file/FileType.scala
@@ -0,0 +1,38 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gimd.file
+
+/**
+ * FileType carries so meta-information about set of Files that conform to
+ * all information carried by FileType.
+ */
+abstract class FileType[T] {
+
+  /**
+   * prefix of File's path or None if there's no common prefix.
+   */
+  def pathPrefix: Option[String]
+
+  /**
+   * suffix of File's path or None if there's no common suffix.
+   */
+  def pathSuffix: Option[String]
+
+  /**
+   * Type of information that File stores.
+   */
+  def userType: UserType[T]
+
+}