java.lang.Object
- org.springframework.batch.item.ItemStreamSupport
- - org.springframework.batch.item.support.AbstractItemStreamItemReader<T>
  - - org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader<T>
    - - org.springframework.batch.item.database.AbstractPagingItemReader<T>

All Implemented Interfaces:
ItemReader<T>, ItemStream, ItemStreamReader<T>, org.springframework.beans.factory.InitializingBean
Direct Known Subclasses:
HibernatePagingItemReader, JdbcPagingItemReader, JpaPagingItemReader
```
public abstract class AbstractPagingItemReader<T>
extends AbstractItemCountingItemStreamItemReader<T>
implements org.springframework.beans.factory.InitializingBean
```
Abstract ItemStreamReader for to extend when reading database records in a paging fashion.
Implementations should execute queries using paged requests of a size specified in setPageSize(int). Additional pages are requested when needed as AbstractItemCountingItemStreamItemReader.read() method is called, returning an object corresponding to current position.
Since:
2.0
Author:
Thomas Risberg, Dave Syer

Field Summary
Fields
Modifier and Type Field Description
protected org.apache.commons.logging.Log logger
protected java.util.List<T> results

Constructor Summary
Constructors
Constructor Description
AbstractPagingItemReader()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`afterPropertiesSet()`	Check mandatory properties.
`protected void`	`doClose()`	Close the resources opened in `AbstractItemCountingItemStreamItemReader.doOpen()`.
`protected abstract void`	`doJumpToPage(int itemIndex)`
`protected void`	`doOpen()`	Open resources necessary to start reading input.
`protected T`	`doRead()`	Read next item from input.
`protected abstract void`	`doReadPage()`
`int`	`getPage()`	The current page number.
`int`	`getPageSize()`	The page size configured for this reader.
`protected void`	`jumpToItem(int itemIndex)`	Move to the given item index.
`void`	`setPageSize(int pageSize)`	The number of rows to retrieve at a time.

Methods inherited from class org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader
close, getCurrentItemCount, isSaveState, open, read, setCurrentItemCount, setMaxItemCount, setSaveState, update

Methods inherited from class org.springframework.batch.item.ItemStreamSupport
getExecutionContextKey, setExecutionContextName, setName

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - logger
```
protected org.apache.commons.logging.Log logger
```
  - results
```
protected volatile java.util.List<T> results
```
- Constructor Detail
  - AbstractPagingItemReader
```
public AbstractPagingItemReader()
```
- Method Detail
  - getPage
```
public int getPage()
```
    The current page number.
    Returns:
    the current page
  - getPageSize
```
public int getPageSize()
```
    The page size configured for this reader.
    Returns:
    the page size
  - setPageSize
```
public void setPageSize(int pageSize)
```
    The number of rows to retrieve at a time.
    Parameters:
    pageSize - the number of rows to fetch per page
  - afterPropertiesSet
```
public void afterPropertiesSet()
                        throws java.lang.Exception
```
    Check mandatory properties.
    Specified by:
    afterPropertiesSet in interface org.springframework.beans.factory.InitializingBean
    Throws:
    java.lang.Exception
    See Also:
    InitializingBean.afterPropertiesSet()
  - doRead
```
protected T doRead()
            throws java.lang.Exception
```
    Description copied from class: AbstractItemCountingItemStreamItemReader
    Read next item from input.
    Specified by:
    doRead in class AbstractItemCountingItemStreamItemReader<T>
    Returns:
    an item or null if the data source is exhausted
    Throws:
    java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework
  - doReadPage
```
protected abstract void doReadPage()
```
  - doOpen
```
protected void doOpen()
               throws java.lang.Exception
```
    Description copied from class: AbstractItemCountingItemStreamItemReader
    Open resources necessary to start reading input.
    Specified by:
    doOpen in class AbstractItemCountingItemStreamItemReader<T>
    Throws:
    java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework
  - doClose
```
protected void doClose()
                throws java.lang.Exception
```
    Description copied from class: AbstractItemCountingItemStreamItemReader
    Close the resources opened in AbstractItemCountingItemStreamItemReader.doOpen().
    Specified by:
    doClose in class AbstractItemCountingItemStreamItemReader<T>
    Throws:
    java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework
  - jumpToItem
```
protected void jumpToItem(int itemIndex)
                   throws java.lang.Exception
```
    Description copied from class: AbstractItemCountingItemStreamItemReader
    Move to the given item index. Subclasses should override this method if there is a more efficient way of moving to given index than re-reading the input using AbstractItemCountingItemStreamItemReader.doRead().
    Overrides:
    jumpToItem in class AbstractItemCountingItemStreamItemReader<T>
    Parameters:
    itemIndex - index of item (0 based) to jump to.
    Throws:
    java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework
  - doJumpToPage
```
protected abstract void doJumpToPage(int itemIndex)
```

Modifier and Type	Field	Description
`protected org.apache.commons.logging.Log`	`logger`
`protected java.util.List<T>`	`results`

Class AbstractPagingItemReader<T>

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader

Methods inherited from class org.springframework.batch.item.ItemStreamSupport

Methods inherited from class java.lang.Object

Field Detail

logger

results

Constructor Detail

AbstractPagingItemReader

Method Detail

getPage

getPageSize

setPageSize

afterPropertiesSet

doRead

doReadPage

doOpen

doClose

jumpToItem

doJumpToPage