Apex: Generic Mass Delete

global class MassDelete implements Database.Batchable<sObject>
{
    global final string query;
	
	global MassDelete(String q)
	{
		query = q;
	}

	global Database.QueryLocator start(Database.BatchableContext BC)
	{
		return Database.getQueryLocator(query);
	}
	
	global void execute(Database.BatchableContext BC, List<sObject> scope)
	{
		delete scope;
	}
	
	global void finish(Database.BatchableContext BC)
	{
		AsyncApexJob a = [Select Id, Status, NumberOfErrors, JobItemsProcessed,
			TotalJobItems, CreatedBy.Email
			from AsyncApexJob where Id =:BC.getJobId()];

		// Send an email to the Apex job's submitter notifying of job completion.  
		Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
		String[] toAddresses = new String[] {a.CreatedBy.Email};
		mail.setToAddresses(toAddresses);
		mail.setSubject('Apex Sharing Recalculation ' + a.Status);
		mail.setPlainTextBody('The batch Apex job processed ' + a.TotalJobItems +
		' batches with '+ a.NumberOfErrors + ' failures.');
		
		Messaging.sendEmail(new Messaging.SingleEmailMessage[] { mail });
	}
}