Class MongoItemReader<T>
- 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>
- org.springframework.batch.item.data.MongoItemReader<T>
- All Implemented Interfaces:
ItemReader<T>
,ItemStream
,ItemStreamReader<T>
,org.springframework.beans.factory.InitializingBean
public class MongoItemReader<T> extends AbstractPaginatedDataItemReader<T> implements org.springframework.beans.factory.InitializingBean
Restartable
ItemReader
that reads documents from MongoDB via a paging technique.If you set JSON String query
setQuery(String)
then it executes the JSON to retrieve the requested documents.If you set Query object
setQuery(Query)
then it executes the Query to retrieve the requested documents.The query is executed using paged requests specified in the
AbstractPaginatedDataItemReader.setPageSize(int)
. Additional pages are requested as needed to provide data when theAbstractItemCountingItemStreamItemReader.read()
method is called.The JSON String query provided supports parameter substitution via ?<index> placeholders where the <index> indicates the index of the parameterValue to substitute.
The implementation is thread-safe between calls to
AbstractItemCountingItemStreamItemReader.open(ExecutionContext)
, but remember to usesaveState=false
if used in a multi-threaded client (no restart available).- Author:
- Michael Minella, Takaaki Iida
Field Summary
Fields inherited from class org.springframework.batch.item.data.AbstractPaginatedDataItemReader
page, pageSize, results
Constructor Summary
Constructors Constructor Description MongoItemReader()
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
afterPropertiesSet()
Checks mandatory propertiesprotected java.util.Iterator<T>
doPageRead()
Method thisItemStreamReader
delegates to for the actual work of reading a page.void
setCollection(java.lang.String collection)
void
setFields(java.lang.String fields)
JSON defining the fields to be returned from the matching documents by MongoDB.void
setHint(java.lang.String hint)
JSON String telling MongoDB what index to use.void
setParameterValues(java.util.List<java.lang.Object> parameterValues)
List
of values to be substituted in for each of the parameters in the query.void
setQuery(java.lang.String queryString)
A JSON formatted MongoDB query.void
setQuery(org.springframework.data.mongodb.core.query.Query query)
A Mongo Query to be used.void
setSort(java.util.Map<java.lang.String,org.springframework.data.domain.Sort.Direction> sorts)
Map
of property names/Sort.Direction
values to sort the input by.void
setTargetType(java.lang.Class<? extends T> type)
The type of object to be returned for eachAbstractItemCountingItemStreamItemReader.read()
call.void
setTemplate(org.springframework.data.mongodb.core.MongoOperations template)
Used to perform operations against the MongoDB instance.Methods inherited from class org.springframework.batch.item.data.AbstractPaginatedDataItemReader
doClose, doOpen, doRead, jumpToItem, setPageSize
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
Method Detail
setQuery
public void setQuery(org.springframework.data.mongodb.core.query.Query query)
A Mongo Query to be used.- Parameters:
query
- Mongo Query to be used.
setTemplate
public void setTemplate(org.springframework.data.mongodb.core.MongoOperations template)
Used to perform operations against the MongoDB instance. Also handles the mapping of documents to objects.- Parameters:
template
- the MongoOperations instance to use- See Also:
MongoOperations
setQuery
public void setQuery(java.lang.String queryString)
A JSON formatted MongoDB query. Parameterization of the provided query is allowed via ?<index> placeholders where the <index> indicates the index of the parameterValue to substitute.- Parameters:
queryString
- JSON formatted Mongo query
setTargetType
public void setTargetType(java.lang.Class<? extends T> type)
The type of object to be returned for eachAbstractItemCountingItemStreamItemReader.read()
call.- Parameters:
type
- the type of object to return
setParameterValues
public void setParameterValues(java.util.List<java.lang.Object> parameterValues)
List
of values to be substituted in for each of the parameters in the query.- Parameters:
parameterValues
- values
setFields
public void setFields(java.lang.String fields)
JSON defining the fields to be returned from the matching documents by MongoDB.- Parameters:
fields
- JSON string that identifies the fields to sort by.
setSort
public void setSort(java.util.Map<java.lang.String,org.springframework.data.domain.Sort.Direction> sorts)
Map
of property names/Sort.Direction
values to sort the input by.- Parameters:
sorts
- map of properties and direction to sort each.
setCollection
public void setCollection(java.lang.String collection)
- Parameters:
collection
- Mongo collection to be queried.
setHint
public void setHint(java.lang.String hint)
JSON String telling MongoDB what index to use.- Parameters:
hint
- string indicating what index to use.
doPageRead
protected java.util.Iterator<T> doPageRead()
Description copied from class:AbstractPaginatedDataItemReader
Method thisItemStreamReader
delegates to for the actual work of reading a page. Each time this method is called, the resultingIterator
should contain the items read within the next page.
If theIterator
is empty or null when it is returned, thisItemReader
will assume that the input has been exhausted.- Specified by:
doPageRead
in classAbstractPaginatedDataItemReader<T>
- Returns:
- an
Iterator
containing the items within a page.
afterPropertiesSet
public void afterPropertiesSet() throws java.lang.Exception
Checks mandatory properties- Specified by:
afterPropertiesSet
in interfaceorg.springframework.beans.factory.InitializingBean
- Throws:
java.lang.Exception
- See Also:
InitializingBean.afterPropertiesSet()