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H2PagingQueryProvider.java
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H2PagingQueryProvider.java
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/*
* Copyright 2006-2022 the original author or authors.
*
* 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
*
* https://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.springframework.batch.item.database.support;
/**
* H2 implementation of a {@link org.springframework.batch.item.database.PagingQueryProvider} using database specific features.
*
* @author Dave Syer
* @author Henning Pöttker
* @since 2.1
*/
public class H2PagingQueryProvider extends AbstractSqlPagingQueryProvider {
@Override
public String generateFirstPageQuery(int pageSize) {
return SqlPagingQueryUtils.generateLimitSqlQuery(this, false, buildLimitClause(pageSize));
}
@Override
public String generateRemainingPagesQuery(int pageSize) {
return SqlPagingQueryUtils.generateLimitSqlQuery(this, true, buildLimitClause(pageSize));
}
private String buildLimitClause(int pageSize) {
return new StringBuilder().append("FETCH NEXT ").append(pageSize).append(" ROWS ONLY").toString();
}
@Override
public String generateJumpToItemQuery(int itemIndex, int pageSize) {
int page = itemIndex / pageSize;
int offset = (page * pageSize) - 1;
offset = offset<0 ? 0 : offset;
String limitClause = new StringBuilder().append("OFFSET ")
.append(offset).append(" ROWS FETCH NEXT 1 ROWS ONLY")
.toString();
return SqlPagingQueryUtils.generateLimitJumpToQuery(this, limitClause);
}
}