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Support limit/offset paging of Collections and Collection.Items

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new method: Collection[] Collection.findAll(limit, offset)
new method: ItemIteractor Collection.getItems(limit, offset)
This commit is contained in:
Peter Dietz
2013-10-18 12:56:18 -04:00
parent 987e835e5e
commit 5eee997e7a
1 changed files with 92 additions and 26 deletions
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118
dspace-api/src/main/java/org/dspace/content/Collection.java
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@@ -7,6 +7,27 @@
*/
package org.dspace.content;
import org.apache.log4j.Logger;
import org.dspace.app.util.AuthorizeUtil;
import org.dspace.authorize.AuthorizeConfiguration;
import org.dspace.authorize.AuthorizeException;
import org.dspace.authorize.AuthorizeManager;
import org.dspace.authorize.ResourcePolicy;
import org.dspace.browse.BrowseException;
import org.dspace.browse.IndexBrowse;
import org.dspace.browse.ItemCountException;
import org.dspace.browse.ItemCounter;
import org.dspace.core.*;
import org.dspace.eperson.Group;
import org.dspace.event.Event;
import org.dspace.handle.HandleManager;
import org.dspace.storage.rdbms.DatabaseManager;
import org.dspace.storage.rdbms.TableRow;
import org.dspace.storage.rdbms.TableRowIterator;
import org.dspace.workflow.WorkflowItem;
import org.dspace.xmlworkflow.storedcomponents.CollectionRole;
import org.dspace.xmlworkflow.storedcomponents.XmlWorkflowItem;
import java.io.IOException;
import java.io.InputStream;
import java.sql.PreparedStatement;
@@ -17,32 +38,6 @@ import java.util.Arrays;
import java.util.List;
import java.util.MissingResourceException;
import org.apache.log4j.Logger;
import org.dspace.app.util.AuthorizeUtil;
import org.dspace.authorize.AuthorizeConfiguration;
import org.dspace.authorize.AuthorizeException;
import org.dspace.authorize.AuthorizeManager;
import org.dspace.authorize.ResourcePolicy;
import org.dspace.browse.BrowseException;
import org.dspace.browse.IndexBrowse;
import org.dspace.browse.ItemCounter;
import org.dspace.browse.ItemCountException;
import org.dspace.core.ConfigurationManager;
import org.dspace.core.Constants;
import org.dspace.core.Context;
import org.dspace.core.I18nUtil;
import org.dspace.core.LicenseManager;
import org.dspace.core.LogManager;
import org.dspace.eperson.Group;
import org.dspace.event.Event;
import org.dspace.handle.HandleManager;
import org.dspace.storage.rdbms.DatabaseManager;
import org.dspace.storage.rdbms.TableRow;
import org.dspace.storage.rdbms.TableRowIterator;
import org.dspace.workflow.WorkflowItem;
import org.dspace.xmlworkflow.storedcomponents.CollectionRole;
import org.dspace.xmlworkflow.storedcomponents.XmlWorkflowItem;
/**
* Class representing a collection.
* <P>
@@ -338,6 +333,56 @@ public class Collection extends DSpaceObject
return collectionArray;
}
/**
* Get all collections in the system. Adds support for limit and offset.
* @param context
* @param limit
* @param offset
* @return
* @throws SQLException
*/
public static Collection[] findAll(Context context, Integer limit, Integer offset) throws SQLException
{
TableRowIterator tri = DatabaseManager.queryTable(context, "collection",
"SELECT * FROM collection ORDER BY name limit ? offset ?", limit, offset);
List<Collection> collections = new ArrayList<Collection>();
try
{
while (tri.hasNext())
{
TableRow row = tri.next();
// First check the cache
Collection fromCache = (Collection) context.fromCache(
Collection.class, row.getIntColumn("collection_id"));
if (fromCache != null)
{
collections.add(fromCache);
}
else
{
collections.add(new Collection(context, row));
}
}
}
finally
{
// close the TableRowIterator to free up resources
if (tri != null)
{
tri.close();
}
}
Collection[] collectionArray = new Collection[collections.size()];
collectionArray = (Collection[]) collections.toArray(collectionArray);
return collectionArray;
}
/**
* Get the in_archive items in this collection. The order is indeterminate.
*
@@ -357,6 +402,27 @@ public class Collection extends DSpaceObject
return new ItemIterator(ourContext, rows);
}
/**
* Get the in_archive items in this collection. The order is indeterminate.
* Provides the ability to use limit and offset, for efficient paging.
* @param limit Max number of results in set
* @param offset Number of results to jump ahead by. 100 = 100th result is first, not 100th page.
* @return an iterator over the items in the collection.
* @throws SQLException
*/
public ItemIterator getItems(Integer limit, Integer offset) throws SQLException
{
String myQuery = "SELECT item.* FROM item, collection2item WHERE "
+ "item.item_id=collection2item.item_id AND "
+ "collection2item.collection_id= ? "
+ "AND item.in_archive='1' limit ? offset ?";
TableRowIterator rows = DatabaseManager.queryTable(ourContext, "item",
myQuery,getID(), limit, offset);
return new ItemIterator(ourContext, rows);
}
/**
* Get all the items in this collection. The order is indeterminate.
*