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1   /*
2    * Copyright 2006-2012 the original author or authors.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.springframework.batch.item.database.support;
18  
19  import org.springframework.batch.item.database.PagingQueryProvider;
20  import org.springframework.util.StringUtils;
21  
22  /**
23   * DB2 implementation of a {@link PagingQueryProvider} using
24   * database specific features.
25   *
26   * @author Thomas Risberg
27   * @author Michael Minella
28   * @since 2.0
29   */
30  public class Db2PagingQueryProvider extends SqlWindowingPagingQueryProvider {
31  
32  	@Override
33  	public String generateFirstPageQuery(int pageSize) {
34  		return SqlPagingQueryUtils.generateLimitSqlQuery(this, false, buildLimitClause(pageSize));
35  	}
36  
37  	@Override
38  	public String generateRemainingPagesQuery(int pageSize) {
39  		if(StringUtils.hasText(getGroupClause())) {
40  			return SqlPagingQueryUtils.generateLimitGroupedSqlQuery(this, true, buildLimitClause(pageSize));
41  		}
42  		else {
43  			return SqlPagingQueryUtils.generateLimitSqlQuery(this, true, buildLimitClause(pageSize));
44  		}
45  	}
46  
47  	@Override
48  	protected Object getSubQueryAlias() {
49  		return "AS TMP_SUB ";
50  	}
51  
52  	private String buildLimitClause(int pageSize) {
53  		return new StringBuilder().append("FETCH FIRST ").append(pageSize).append(" ROWS ONLY").toString();
54  	}
55  
56  }