[DS-728] Add core curation code & workflow support

git-svn-id: http://scm.dspace.org/svn/repo/dspace/trunk@5674 9c30dcfa-912a-0410-8fc2-9e0234be79fd

dspace-api/src/main/java/org/dspace/curate/AbstractCurationTask.java

@@ -0,0 +1,154 @@
+/*
+ * 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://dspace.org/license/
+ */
+
+package org.dspace.curate;
+
+import java.io.IOException;
+import java.sql.SQLException;
+
+import org.dspace.content.Collection;
+import org.dspace.content.Community;
+import org.dspace.content.DSpaceObject;
+import org.dspace.content.Item;
+import org.dspace.content.ItemIterator;
+import org.dspace.core.Constants;
+import org.dspace.core.Context;
+import org.dspace.handle.HandleManager;
+
+/**
+ * AbstractCurationTask encapsulates a few common patterns of task use,
+ * resources, and convenience methods.
+ * 
+ * @author richardrodgers
+ */
+public abstract class AbstractCurationTask implements CurationTask
+{
+    // invoking curator
+    protected Curator curator = null;
+    // curator-assigned taskId
+    protected String taskId = null;
+
+    @Override
+    public void init(Curator curator, String taskId) throws IOException
+    {
+        this.curator = curator;
+        this.taskId = taskId;
+    }
+
+    @Override
+    public abstract int perform(DSpaceObject dso) throws IOException;
+    
+    /**
+     * Distributes a task through a DSpace container - a convenience method
+     * for tasks declaring the <code>@Distributive</code> property. Users must
+     * override the 'performItem' invoked by this method.
+     * 
+     * @param dso
+     * @throws IOException
+     */
+    protected void distribute(DSpaceObject dso) throws IOException
+    {
+        try
+        {
+            int type = dso.getType();
+            if (Constants.ITEM == type)
+            {
+                performItem((Item)dso);
+            }
+            else if (Constants.COLLECTION == type)
+            {
+                ItemIterator iter = ((Collection)dso).getItems();
+                while (iter.hasNext())
+                {
+                    performItem(iter.next());
+                }
+            }
+            else if (Constants.COMMUNITY == type)
+            {
+                Community comm = (Community)dso;
+                for (Community subcomm : comm.getSubcommunities())
+                {
+                    distribute(subcomm);
+                }
+                for (Collection coll : comm.getCollections())
+                {
+                    distribute(coll);
+                }
+            }
+        }
+        catch (SQLException sqlE)
+        {
+            throw new IOException(sqlE.getMessage(), sqlE);
+        }       
+    }
+    
+    /**
+     * Performs task upon an Item. Must be overridden if <code>distribute</code>
+     * method is used.
+     * 
+     * @param item
+     * @throws SQLException
+     * @throws IOException
+     */
+    protected void performItem(Item item) throws SQLException, IOException
+    {
+        // no-op - override when using 'distribute' method
+    }
+
+    @Override
+    public int perform(Context ctx, String id) throws IOException
+    {
+        DSpaceObject dso = dereference(ctx, id);
+        return (dso != null) ? perform(dso) : Curator.CURATE_FAIL;
+    }
+    
+    /**
+     * Returns a DSpaceObject for passed identifier, if it exists
+     * 
+     * @param ctx
+     *        DSpace context
+     * @param id 
+     *        canonical id of object
+     * @return dso
+     *        DSpace object, or null if no object with id exists
+     * @throws IOException
+     */
+    protected DSpaceObject dereference(Context ctx, String id) throws IOException
+    {
+        try
+        {
+            return HandleManager.resolveToObject(ctx, id);
+        }
+        catch (SQLException sqlE)
+        {
+            throw new IOException(sqlE.getMessage(), sqlE);
+        }
+    }
+
+    /**
+     * Sends message to the reporting stream
+     * 
+     * @param message
+     *        the message to stream
+     */
+    protected void report(String message)
+    {
+        curator.report(message);
+    }
+
+    /**
+     * Assigns the result of the task performance
+     * 
+     * @param result
+     *        the result string
+     */
+    protected void setResult(String result)
+    {
+        curator.setResult(taskId, result);
+    }
+}