org.hdpagination.dataaccess.jdbc
Class JdbcQueryTemplate

java.lang.Object
  org.hdpagination.dataaccess.jdbc.JdbcQueryTemplate

All Implemented Interfaces:

QueryTemplate

Direct Known Subclasses:

DB2JdbcQueryTemplate, HSQLDBJdbcQueryTemplate, MySqlJdbcQueryTemplate, OracleJdbcQueryTemplate, PostgreSQLQueryTemplate, SQLAnywhereJdbcQueryTemplate, StandardJdbcQueryTemplate

public abstract class JdbcQueryTemplate
extends java.lang.Object
implements QueryTemplate

The type of QueryTemplate to run a pagination based query against JDBC. Different of database providers (e.g. Oracle, MySQl, DB2, HSQLDB) have their own implementation class which extends from this abstract class. They share common code to execute query but have different way to translate the original sql to a pagination based sql based on their own sql syntax. Because of this, QueryTemplate implementation class for particular database provider must implement its own method convertPaginationSql. For some provider,it even has to override the method convertCountSql if the default way (implemented in this class) to translate the original sql to 'count total records' sql does not work properly in that database.

Since:

1.0

Author:

Liangfeng Ren

Constructor Summary

JdbcQueryTemplate(javax.sql.DataSource dataSource)

Method Summary

protected java.lang.String	convertCountSql(java.lang.String querySql) Translate original query sql to the sql which can be used to query the count of total records.
protected abstract java.lang.String	convertPaginationSql(java.lang.String sql, int pageNo, int pageSize) Translate original query sql to pagination based sql
int	countRows(QueryCallback callback) query total number of records for this search
java.util.List	query(QueryCallback callback, int pageSize, int pageNo) execute query and return only one page of data

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JdbcQueryTemplate

public JdbcQueryTemplate(javax.sql.DataSource dataSource)

Parameters:

dataSource - DataSource that the query is executed against

Method Detail

query

public java.util.List query(QueryCallback callback,
                            int pageSize,
                            int pageNo)

Description copied from interface: QueryTemplate

execute query and return only one page of data

Specified by:

query in interface QueryTemplate

pageSize - number of records per page

pageNo - index of current page,index begins with 0.

Returns:

countRows

public int countRows(QueryCallback callback)

Description copied from interface: QueryTemplate

query total number of records for this search

Specified by:

countRows in interface QueryTemplate

Returns:

convertPaginationSql

protected abstract java.lang.String convertPaginationSql(java.lang.String sql,
                                                         int pageNo,
                                                         int pageSize)

Translate original query sql to pagination based sql

Parameters:

sql - original sql

pageNo - current page number (start from 0)

pageSize - how many records is displayed in one page

Returns:

return pagination based sql

convertCountSql

protected java.lang.String convertCountSql(java.lang.String querySql)

Translate original query sql to the sql which can be used to query the count of total records. If this default translation does not work in one particular database, its corresponding subclass of JdbcQueryTemplate should override this method.

Parameters:

querySql - original sql

Returns:

return sql to query the count of total records.