Add and implement Identified interface.

[Sone.git] / src / main / java / net / pterodactylus / sone / data / Identified.java

diff --git a/src/main/java/net/pterodactylus/sone/data/Identified.java b/src/main/java/net/pterodactylus/sone/data/Identified.java
new file mode 100644 (file)
index 0000000..f12f842
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+++ b/src/main/java/net/pterodactylus/sone/data/Identified.java
@@ -0,0 +1,46 @@
+/*
+ * Sone - Identified.java - Copyright © 2013 David Roden
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.sone.data;
+
+import com.google.common.base.Function;
+import com.google.common.base.Optional;
+
+/**
+ * Interface for all objects that expose an ID.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public interface Identified {
+
+       /** Function to extract the ID from an optional. */
+       public static final Function<Optional<? extends Identified>, Optional<String>> GET_ID = new Function<Optional<? extends Identified>, Optional<String>>() {
+
+               @Override
+               public Optional<String> apply(Optional<? extends Identified> identified) {
+                       return identified.isPresent() ? Optional.of(identified.get().getId()) : Optional.<String>absent();
+               }
+       };
+
+       /**
+        * Returns the ID of this element.
+        *
+        * @return The ID of this element
+        */
+       public String getId();
+
+}