public class MongoItemReader<T> extends AbstractPaginatedDataItemReader<T> implements org.springframework.beans.factory.InitializingBean
Restartable ItemReader that reads documents from MongoDB
via a paging technique.
It executes the JSON setQuery(String) 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 the AbstractItemCountingItemStreamItemReader.read() method is called.
The JSON 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 use saveState=false
if used in a multi-threaded client (no restart available.
page, pageSize, results| Constructor and Description |
|---|
MongoItemReader() |
| Modifier and Type | Method and Description |
|---|---|
void |
afterPropertiesSet()
Checks mandatory properties
|
protected Iterator<T> |
doPageRead()
Method this
ItemStreamReader delegates to
for the actual work of reading a page. |
void |
setFields(String fields)
JSON defining the fields to be returned from the matching documents
by MongoDB.
|
void |
setHint(String hint)
JSON String telling MongoDB what index to use.
|
void |
setParameterValues(List<Object> parameterValues)
List of values to be substituted in for each of the
parameters in the query. |
void |
setQuery(String query)
A JSON formatted MongoDB query.
|
void |
setSort(Map<String,org.springframework.data.domain.Sort.Direction> sorts)
Map of property names/Sort.Direction values to
sort the input by. |
void |
setTargetType(Class<? extends T> type)
The type of object to be returned for each
AbstractItemCountingItemStreamItemReader.read() call. |
void |
setTemplate(org.springframework.data.mongodb.core.MongoOperations template)
Used to perform operations against the MongoDB instance.
|
doClose, doOpen, doRead, jumpToItem, setPageSizeclose, getCurrentItemCount, isSaveState, open, read, setCurrentItemCount, setMaxItemCount, setName, setSaveState, updategetExecutionContextKey, setExecutionContextNamepublic void setTemplate(org.springframework.data.mongodb.core.MongoOperations template)
template - the MongoOperations instance to useMongoOperationspublic void setQuery(String query)
query - JSON formatted Mongo querypublic void setTargetType(Class<? extends T> type)
AbstractItemCountingItemStreamItemReader.read() call.type - the type of object to returnpublic void setParameterValues(List<Object> parameterValues)
List of values to be substituted in for each of the
parameters in the query.parameterValues - public void setFields(String fields)
fields - JSON string that identifies the fields to sorty by.public void setSort(Map<String,org.springframework.data.domain.Sort.Direction> sorts)
Map of property names/Sort.Direction values to
sort the input by.sorts - map of properties and direction to sort each.public void setHint(String hint)
hint - string indicating what index to use.protected Iterator<T> doPageRead()
AbstractPaginatedDataItemReaderItemStreamReader 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.
Iterator is empty or null when it is
returned, this ItemReader will assume that the
input has been exhausted.doPageRead in class AbstractPaginatedDataItemReader<T>Iterator containing the items within a page.Copyright © 2013 SpringSource. All Rights Reserved.