/**
* Copyright 2010 Daniel Guermeur and Amy Unruh
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* See http://connectrapp.appspot.com/ for a demo, and links to more information
* about this app and the book that it accompanies.
*/
package com.metadot.book.connectr.server.migrations;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.jdo.PersistenceManager;
import javax.jdo.Query;
import com.google.appengine.api.datastore.Cursor;
import org.datanucleus.store.appengine.query.JDOCursorHelper;
import com.metadot.book.connectr.server.PMF;
import com.metadot.book.connectr.server.domain.StreamItem;
import com.metadot.book.connectr.server.migrations.Migration;
/**
* StreamItemPurge is a migration to remove from the Datastore all
* StreamItem entities older than a given date.
*/
public class StreamItemPurge implements Migration {
@SuppressWarnings("unchecked")
public Map<String, String> migrate_down(String cursorString, int range, Map<String,String> params) {
Query q = null;
Date prior = null;
Long priorl = null;
List<StreamItem> results = null;
int hoursOld = 168; // default number of hours older than which to purge
Long ts = (new Date()).getTime();
if (params != null) {
try {
String hstring = (String) params.get("hours");
hoursOld = Integer.parseInt(hstring);
}
catch (Exception e1) {
// e1.printStackTrace();
}
try {
String tsstring = (String) params.get("ts");
ts = Long.parseLong(tsstring);
}
catch (Exception e2) {
// just catch the parse exception.
// e2.printStackTrace();
}
priorl = ts - (1000 * (hoursOld * 3600));
prior = new Date(priorl);
}
PersistenceManager pm = PMF.get().getPersistenceManager();
try {
if (prior != null) {
q = pm.newQuery(StreamItem.class, "date <= :d1");
}
else {
q = pm.newQuery(StreamItem.class);
}
if (cursorString != null) {
Cursor cursor = Cursor.fromWebSafeString(cursorString);
Map<String, Object> extensionMap = new HashMap<String, Object>();
extensionMap.put(JDOCursorHelper.CURSOR_EXTENSION, cursor);
q.setExtensions(extensionMap);
}
q.setRange(0, range);
if (prior == null) {
results = (List<StreamItem>) q.execute();
}
else {
results = (List<StreamItem>) q.execute(prior);
}
if (results.iterator().hasNext()) {
for (StreamItem streamItem : results) {
pm.deletePersistent(streamItem);
}
Cursor cursor = JDOCursorHelper.getCursor(results);
cursorString = cursor.toWebSafeString();
}
else {
// no results
cursorString = null;
}
}
finally {
q.closeAll();
pm.close();
}
Map<String,String> res = new HashMap<String,String>();
res.put("cursor", cursorString);
res.put("hours", ""+hoursOld);
res.put("ts", ""+ ts);
return res;
}
// a no-op for this class
public Map<String, String> migrate_up(String cs, int range, Map<String,String> params) {
return null;
}
}