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/**
*
* Copyright 2005 The Apache Software Foundation or its licensors, as applicable.
*
* 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.
*/
package org.apache.tuscany.das.rdb;
import commonj.sdo.DataObject;
/**
* An iterator-like interface to conveniently move through chunks of data. The
* idea is that a Pager works with a read Command. The read command returns a
* large amount of data and the client wants to work with chunks of it at a
* time. So the Pager is created on the command and each call to next returns
* the next chunk of data. This is done completely disconnected. No cursor is
* maintained between calls to #next.
*
* TODO - This is very preliminary. We need to look at this interface in the
* context of disonnected scenarios such as a web app. The Pager instance will
* probably be saved in session so it must be very light and cannot reference a
* connection. Also, we probably need to define a factory or add a method to set
* page size.
*
*
*/
public interface Pager {
/**
* Get the next page of data
*
* @return the next page of data
*/
public DataObject next();
/**
* Get the page prior to the last page returned
*
* @return the previous page
*/
public DataObject previous();
/**
* Return a specific identified page.
*
* @param page
* The number of the page to return
* @return the indicated page
*/
public DataObject getPage(int page);
}
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