Package org.springframework.batch.item.database.support

Class AbstractSqlPagingQueryProvider

java.lang.Object
org.springframework.batch.item.database.support.AbstractSqlPagingQueryProvider
All Implemented Interfaces:
PagingQueryProvider
Direct Known Subclasses:
Db2PagingQueryProvider, DerbyPagingQueryProvider, H2PagingQueryProvider, HanaPagingQueryProvider, HsqlPagingQueryProvider, MariaDBPagingQueryProvider, MySqlPagingQueryProvider, OraclePagingQueryProvider, PostgresPagingQueryProvider, SqlitePagingQueryProvider, SqlServerPagingQueryProvider, SybasePagingQueryProvider
public abstract class AbstractSqlPagingQueryProvider extends Object implements PagingQueryProvider
Abstract SQL Paging Query Provider to serve as a base class for all provided SQL paging query providers.

Any implementation must provide a way to specify the select clause, from clause and optionally a where clause. In addition a way to specify a single column sort key must also be provided. This sort key will be used to provide the paging functionality. It is recommended that there should be an index for the sort key to provide better performance.

Provides properties and preparation for the mandatory "selectClause" and "fromClause" as well as for the optional "whereClause". Also provides property for the mandatory "sortKeys". Note: The columns that make up the sort key must be a true key and not just a column to order by. It is important to have a unique key constraint on the sort key to guarantee that no data is lost between executions.

Since:
2.0
Author:
Thomas Risberg, Dave Syer, Michael Minella, Mahmoud Ben Hassine, Benjamin Hetz, Stefano Cordio

  • Constructor Details

    • AbstractSqlPagingQueryProvider

      public AbstractSqlPagingQueryProvider()

  • Method Details

    • setGroupClause

      public void setGroupClause(@Nullable String groupClause)
      The setter for the group by clause
      Parameters:
      groupClause - SQL GROUP BY clause part of the SQL query string

    • getGroupClause

      public @Nullable String getGroupClause()
      The getter for the group by clause
      Returns:
      SQL GROUP BY clause part of the SQL query string

    • setSelectClause

      public void setSelectClause(String selectClause)
      Parameters:
      selectClause - SELECT clause part of SQL query string

    • getSelectClause

      protected @Nullable String getSelectClause()
      Returns:
      SQL SELECT clause part of SQL query string

    • setFromClause

      public void setFromClause(String fromClause)
      Parameters:
      fromClause - FROM clause part of SQL query string

    • getFromClause

      protected @Nullable String getFromClause()
      Returns:
      SQL FROM clause part of SQL query string

    • setWhereClause

      public void setWhereClause(@Nullable String whereClause)
      Parameters:
      whereClause - WHERE clause part of SQL query string

    • getWhereClause

      protected @Nullable String getWhereClause()
      Returns:
      SQL WHERE clause part of SQL query string

    • setSortKeys

      public void setSortKeys(Map<String,Order> sortKeys)
      Parameters:
      sortKeys - key to use to sort and limit page content

    • getSortKeys

      public Map<String,Order> getSortKeys()
      A Map<String, Boolean> of sort columns as the key and boolean for ascending/descending (ascending = true).
      Specified by:
      getSortKeys in interface PagingQueryProvider
      Returns:
      keys to use to sort and limit page content

    • getParameterCount

      public int getParameterCount()
      Description copied from interface: PagingQueryProvider
      The number of parameters that are declared in the query
      Specified by:
      getParameterCount in interface PagingQueryProvider
      Returns:
      number of parameters

    • isUsingNamedParameters

      public boolean isUsingNamedParameters()
      Description copied from interface: PagingQueryProvider
      Indicate whether the generated queries use named parameter syntax.
      Specified by:
      isUsingNamedParameters in interface PagingQueryProvider
      Returns:
      true if named parameter syntax is used

    • getSortKeyPlaceHolder

      public String getSortKeyPlaceHolder(String keyName)
      The sort key placeholder will vary depending on whether named parameters or traditional placeholders are used in query strings.
      Specified by:
      getSortKeyPlaceHolder in interface PagingQueryProvider
      Parameters:
      keyName - The sort key name
      Returns:
      placeholder for sortKey.

    • init

      public void init(DataSource dataSource) throws Exception
      Check mandatory properties.
      Specified by:
      init in interface PagingQueryProvider
      Parameters:
      dataSource - DataSource to use for any initialization
      Throws:
      Exception - for errors when initializing
      See Also:
      • InitializingBean.afterPropertiesSet()

    • generateFirstPageQuery

      public abstract String generateFirstPageQuery(int pageSize)
      Method generating the query string to be used for retrieving the first page. This method must be implemented in subclasses.
      Specified by:
      generateFirstPageQuery in interface PagingQueryProvider
      Parameters:
      pageSize - number of rows to read per page
      Returns:
      query string

    • generateRemainingPagesQuery

      public abstract String generateRemainingPagesQuery(int pageSize)
      Method generating the query string to be used for retrieving the pages following the first page. This method must be implemented in subclasses.
      Specified by:
      generateRemainingPagesQuery in interface PagingQueryProvider
      Parameters:
      pageSize - number of rows to read per page
      Returns:
      query string

    • getSortKeysWithoutAliases

      public Map<String,Order> getSortKeysWithoutAliases()
      Description copied from interface: PagingQueryProvider
      The sort key (unique single column name) without alias.
      Specified by:
      getSortKeysWithoutAliases in interface PagingQueryProvider
      Returns:
      sortKey key to use to sort and limit page content (without alias)