org.springframework.batch.item.database

Interface PagingQueryProvider

All Known Implementing Classes:

AbstractSqlPagingQueryProvider, Db2PagingQueryProvider, DerbyPagingQueryProvider, H2PagingQueryProvider, HsqlPagingQueryProvider, MySqlPagingQueryProvider, OraclePagingQueryProvider, PostgresPagingQueryProvider, SqlitePagingQueryProvider, SqlServerPagingQueryProvider, SqlWindowingPagingQueryProvider, SybasePagingQueryProvider

public interface PagingQueryProvider

Interface defining the functionality to be provided for generating paging queries for use with Paging Item Readers.

Since:

2.0

Author:

Thomas Risberg, Michael Minella

Method Summary

Modifier and Type	Method and Description
java.lang.String	generateFirstPageQuery(int pageSize) Generate the query that will provide the first page, limited by the page size.
java.lang.String	generateJumpToItemQuery(int itemIndex, int pageSize) Generate the query that will provide the jump to item query.
java.lang.String	generateRemainingPagesQuery(int pageSize) Generate the query that will provide the first page, limited by the page size.
int	getParameterCount() The number of parameters that are declared in the query
java.lang.String	getSortKeyPlaceHolder(java.lang.String keyName) Returns either a String to be used as the named placeholder for a sort key value (based on the column name) or a ? for unnamed parameters.
java.util.Map<java.lang.String,Order>	getSortKeys() The sort keys.
java.util.Map<java.lang.String,Order>	getSortKeysWithoutAliases() The sort key (unique single column name) without alias.
void	init(javax.sql.DataSource dataSource) Initialize the query provider using the provided DataSource if necessary.
boolean	isUsingNamedParameters() Indicate whether the generated queries use named parameter syntax.

Method Detail

init

void init(javax.sql.DataSource dataSource)
   throws java.lang.Exception

Initialize the query provider using the provided DataSource if necessary.

Parameters:

dataSource - DataSource to use for any initialization

Throws:

java.lang.Exception - for errors when initializing

generateFirstPageQuery

java.lang.String generateFirstPageQuery(int pageSize)

Generate the query that will provide the first page, limited by the page size.

Parameters:

pageSize - number of rows to read for each page

Returns:

the generated query

generateRemainingPagesQuery

java.lang.String generateRemainingPagesQuery(int pageSize)

Generate the query that will provide the first page, limited by the page size.

Parameters:

pageSize - number of rows to read for each page

Returns:

the generated query

generateJumpToItemQuery

java.lang.String generateJumpToItemQuery(int itemIndex,
                                         int pageSize)

Generate the query that will provide the jump to item query. The itemIndex provided could be in the middle of the page and together with the page size it will be used to calculate the last index of the preceding page to be able to retrieve the sort key for this row.

Parameters:

itemIndex - the index for the next item to be read

pageSize - number of rows to read for each page

Returns:

the generated query

getParameterCount

int getParameterCount()

The number of parameters that are declared in the query

Returns:

number of parameters

isUsingNamedParameters

boolean isUsingNamedParameters()

Indicate whether the generated queries use named parameter syntax.

Returns:

true if named parameter syntax is used

getSortKeys

java.util.Map<java.lang.String,Order> getSortKeys()

The sort keys. A Map of the columns that make up the key and a Boolean indicating ascending or descending (ascending = true).

Returns:

the sort keys used to order the query

getSortKeyPlaceHolder

java.lang.String getSortKeyPlaceHolder(java.lang.String keyName)

Returns either a String to be used as the named placeholder for a sort key value (based on the column name) or a ? for unnamed parameters.

Parameters:

keyName - The sort key name

Returns:

The string to be used for a parameterized query.

getSortKeysWithoutAliases

java.util.Map<java.lang.String,Order> getSortKeysWithoutAliases()

The sort key (unique single column name) without alias.

Returns:

the sort key used to order the query (without alias)