DS-4166 move IndexableObject to the discovery package

dspace-api/src/main/java/org/dspace/discovery/IndexableObject.java

@@ -0,0 +1,52 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.discovery;
+
+import java.io.Serializable;
+
+import org.dspace.core.Constants;
+
+/**
+ * This is the basic interface that a data model entity need to implement to be indexable in Discover
+ * 
+ * @author Andrea Bollini (andrea.bollini at 4science.it)
+ *
+ * @param <PK>
+ *            the Class of the primary key
+ */
+public interface IndexableObject<PK extends Serializable> {
+
+    /**
+     * 
+     * @return the integer constant representing the Entity Type, @see {@link Constants}
+     */
+    public int getType();
+
+    /**
+     * 
+     * @return the primary key of the Entity instance
+     */
+    public PK getID();
+
+    /**
+     * 
+     * @return an unique id to index
+     */
+    default String getUniqueIndexID() {
+        return getType() + "-" + getID().toString();
+    }
+
+    /**
+     * 
+     * @return a textual alias of the Entity Type @see {@link #getType()}
+     */
+    default public String getTypeText() {
+        return Constants.typeText[getType()];
+    };
+
+}