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.data.AbstractPaginatedDataItemReader<T>

Type Parameters:
T - Type of item to be read
All Implemented Interfaces:
ItemReader<T>, ItemStream, ItemStreamReader<T>
Direct Known Subclasses:
AbstractNeo4jItemReader, MongoItemReader
```
public abstract class AbstractPaginatedDataItemReader<T>
extends AbstractItemCountingItemStreamItemReader<T>
```
A base class that handles basic reading logic based on the paginated semantics of Spring Data's paginated facilities. It also handles the semantics required for restartability based on those facilities.
Since:
2.2
Author:
Michael Minella, Glenn Renfro

Field Summary
Fields
Modifier and Type Field Description
protected int page
protected int pageSize
protected java.util.Iterator<T> results

Constructor Summary
Constructors
Constructor Description
AbstractPaginatedDataItemReader()

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`doClose()`	Close the resources opened in `AbstractItemCountingItemStreamItemReader.doOpen()`.
`protected void`	`doOpen()`	Open resources necessary to start reading input.
`protected abstract java.util.Iterator<T>`	`doPageRead()`	Method this `ItemStreamReader` delegates to for the actual work of reading a page.
`protected T`	`doRead()`	Read next item from input.
`protected void`	`jumpToItem(int itemLastIndex)`	Move to the given item index.
`void`	`setPageSize(int pageSize)`	The number of items to be read with each page.

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
  - page
```
protected volatile int page
```
  - pageSize
```
protected int pageSize
```
  - results
```
protected java.util.Iterator<T> results
```
- Constructor Detail
  - AbstractPaginatedDataItemReader
```
public AbstractPaginatedDataItemReader()
```
- Method Detail
  - setPageSize
```
public void setPageSize(int pageSize)
```
    The number of items to be read with each page.
    Parameters:
    pageSize - the number of items. pageSize must be greater than zero.
  - 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
  - doPageRead
```
protected abstract java.util.Iterator<T> doPageRead()
```
    Method this ItemStreamReader delegates to for the actual work of reading a page. Each time this method is called, the resulting Iterator should contain the items read within the next page.
    
    If the Iterator is empty or null when it is returned, this ItemReader will assume that the input has been exhausted.
    Returns:
    an Iterator containing the items within a page.
  - 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 itemLastIndex)
                   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:
    itemLastIndex - index of item (0 based) to jump to.
    Throws:
    java.lang.Exception - Allows subclasses to throw checked exceptions for interpretation by the framework

Modifier and Type	Field	Description
`protected int`	`page`
`protected int`	`pageSize`
`protected java.util.Iterator<T>`	`results`

Class AbstractPaginatedDataItemReader<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

page

pageSize

results

Constructor Detail

AbstractPaginatedDataItemReader

Method Detail

setPageSize

doRead

doPageRead

doOpen

doClose

jumpToItem