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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
*/
DataObject next();
/**
* Get the page prior to the last page returned
*
* @return the previous page
*/
DataObject previous();
/**
* Return a specific identified page.
*
* @param page
* The number of the page to return
* @return the indicated page
*/
DataObject getPage(int page);
}
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