Add base implementation of an album builder.

diff --git a/src/main/java/net/pterodactylus/sone/data/impl/AbstractAlbumBuilder.java b/src/main/java/net/pterodactylus/sone/data/impl/AbstractAlbumBuilder.java
new file mode 100644 (file)
index 0000000..312c795
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sone/data/impl/AbstractAlbumBuilder.java
@@ -0,0 +1,64 @@
+/*
+ * Sone - AbstractAlbumBuilder.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.impl;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import net.pterodactylus.sone.database.AlbumBuilder;
+
+/**
+ * Abstract {@link AlbumBuilder} implementation. It stores the state of the new
+ * album and performs validation, you only need to implement {@link #build()}.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class AbstractAlbumBuilder implements AlbumBuilder {
+
+       /** Whether to create an album with a random ID. */
+       protected boolean randomId;
+
+       /** The ID of the album to create. */
+       protected String id;
+
+       @Override
+       public AlbumBuilder randomId() {
+               randomId = true;
+               return this;
+       }
+
+       @Override
+       public AlbumBuilder withId(String id) {
+               this.id = id;
+               return this;
+       }
+
+       //
+       // PROTECTED METHODS
+       //
+
+       /**
+        * Validates the state of this post builder.
+        *
+        * @throws IllegalStateException
+        *              if the state is not valid for building a new post
+        */
+       protected void validate() throws IllegalStateException {
+               checkState((randomId && (id == null)) || (!randomId && (id != null)), "exactly one of random ID or custom ID must be set");
+       }
+
+}