MappedSelect (cayenne-server: Cayenne Server 4.0.2 API)

java.lang.Object
- org.apache.cayenne.query.IndirectQuery
- - org.apache.cayenne.query.AbstractMappedQuery
  - - org.apache.cayenne.query.MappedSelect<T>

All Implemented Interfaces:

Serializable, Query, Select<T>
```
public class MappedSelect<T>
extends AbstractMappedQuery
implements Select<T>
```
A query that represents a named parameterized selecting query stored in the mapping. The actual query is resolved during execution.

Since:

4.0

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`protected Integer`	`fetchLimit`
`protected Integer`	`fetchOffset`
`protected boolean`	`forceNoCache`
`protected Integer`	`pageSize`
`protected Class<T>`	`resultClass`
`protected Integer`	`statementFetchSize`

Fields inherited from class org.apache.cayenne.query.AbstractMappedQuery
params, queryName

Fields inherited from class org.apache.cayenne.query.IndirectQuery
dataMap, lastResolver, name, replacementQuery

Constructor Summary

Constructors
Modifier Constructor and Description

protected MappedSelect(String queryName)

protected MappedSelect(String queryName, Class<T> resultClass)

Constructors
Modifier	Constructor and Description
`protected`	`MappedSelect(String queryName)`
`protected`	`MappedSelect(String queryName, Class<T> resultClass)`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`ResultBatchIterator<T>`	`batchIterator(ObjectContext context, int size)` Creates a ResultBatchIterator based on the provided context and batch size.
`protected Query`	`createReplacementQuery(EntityResolver resolver)` Creates a substitute query.
`MappedSelect<T>`	`forceNoCache()` Forces query cache to be refreshed during the execution of this query.
`void`	`iterate(ObjectContext context, ResultIteratorCallback<T> callback)` Creates a ResultIterator based on the provided context and passes it to a callback for processing.
`ResultIterator<T>`	`iterator(ObjectContext context)` Creates a ResultIterator based on the provided context.
`MappedSelect<T>`	`limit(int fetchLimit)` Resets query fetch limit - a parameter that defines max number of objects that should be ever be fetched from the database.
`MappedSelect<T>`	`offset(int fetchOffset)` Resets query fetch offset - a parameter that defines how many objects should be skipped when reading data from the database.
`MappedSelect<T>`	`pageSize(int pageSize)` Resets query page size.
`MappedSelect<T>`	`param(String name, Object value)`
`MappedSelect<T>`	`params(Map<String,?> parameters)`
`static MappedSelect<?>`	`query(String queryName)` Loads query with the given name from the mapping configuration.
`static <T> MappedSelect<T>`	`query(String queryName, Class<T> rootClass)` Loads query with the given name, which selects objects of a given persistent class, from the mapping configuration.
`List<T>`	`select(ObjectContext context)` Selects objects using provided context.
`T`	`selectFirst(ObjectContext context)` Selects a single object using provided context.
`T`	`selectOne(ObjectContext context)` Selects a single object using provided context.
`MappedSelect<T>`	`statementFetchSize(int statementFetchSize)` Sets fetch size of the PreparedStatement generated for this query.

Methods inherited from class org.apache.cayenne.query.AbstractMappedQuery
name

Methods inherited from class org.apache.cayenne.query.IndirectQuery
createSQLAction, getDataMap, getMetaData, getName, getReplacementQuery, route, setDataMap, setName

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

Methods inherited from interface org.apache.cayenne.query.Query
createSQLAction, getDataMap, getMetaData, getName, route

- Field Detail
  - resultClass
```
protected Class<T> resultClass
```
  - fetchLimit
```
protected Integer fetchLimit
```
  - fetchOffset
```
protected Integer fetchOffset
```
  - statementFetchSize
```
protected Integer statementFetchSize
```
  - pageSize
```
protected Integer pageSize
```
  - forceNoCache
```
protected boolean forceNoCache
```
- Constructor Detail
  - MappedSelect
```
protected MappedSelect(String queryName)
```
  - MappedSelect
```
protected MappedSelect(String queryName,
                       Class<T> resultClass)
```
- Method Detail
  - query
```
public static <T> MappedSelect<T> query(String queryName,
                                        Class<T> rootClass)
```
    Loads query with the given name, which selects objects of a given persistent class, from the mapping configuration.
    
    Parameters:
    
    queryName - name of the mapped query
    
    rootClass - the Class of objects fetched by this query
  - query
```
public static MappedSelect<?> query(String queryName)
```
    Loads query with the given name from the mapping configuration.
    
    Parameters:
    
    queryName - name of the mapped query
  - limit
```
public MappedSelect<T> limit(int fetchLimit)
```
    Resets query fetch limit - a parameter that defines max number of objects that should be ever be fetched from the database.
  - offset
```
public MappedSelect<T> offset(int fetchOffset)
```
    Resets query fetch offset - a parameter that defines how many objects should be skipped when reading data from the database.
  - statementFetchSize
```
public MappedSelect<T> statementFetchSize(int statementFetchSize)
```
    Sets fetch size of the PreparedStatement generated for this query. Only non-negative values would change the default size.
    
    See Also:
    
    Statement.setFetchSize(int)
  - pageSize
```
public MappedSelect<T> pageSize(int pageSize)
```
    Resets query page size. A non-negative page size enables query result pagination that saves memory and processing time for large lists if only parts of the result are ever going to be accessed.
  - forceNoCache
```
public MappedSelect<T> forceNoCache()
```
    Forces query cache to be refreshed during the execution of this query.
  - params
```
public MappedSelect<T> params(Map<String,?> parameters)
```
    Overrides:
    
    params in class AbstractMappedQuery
  - param
```
public MappedSelect<T> param(String name,
                             Object value)
```
    Overrides:
    
    param in class AbstractMappedQuery
  - select
```
public List<T> select(ObjectContext context)
```
    Description copied from interface: Select
    
    Selects objects using provided context.
    Essentially the inversion of "ObjectContext.select(Select)".
    
    Specified by:
    
    select in interface Select<T>
  - selectOne
```
public T selectOne(ObjectContext context)
```
    Description copied from interface: Select
    
    Selects a single object using provided context. The query is expected to match zero or one object. It returns null if no objects were matched. If query matched more than one object, CayenneRuntimeException is thrown.
    Essentially the inversion of "ObjectContext.selectOne(Select)".
    
    Specified by:
    
    selectOne in interface Select<T>
  - selectFirst
```
public T selectFirst(ObjectContext context)
```
    Description copied from interface: Select
    
    Selects a single object using provided context. The query itself can match any number of objects, but will return only the first one. It returns null if no objects were matched.
    If it matched more than one object, the first object from the list is returned. This makes 'selectFirst' different from Select.selectOne(ObjectContext), which would throw in this situation. 'selectFirst' is useful e.g. when the query is ordered and we only want to see the first object (e.g. "most recent news article"), etc.
    Selecting the first object via "Select.selectFirst(ObjectContext)" is more comprehensible than selecting via "ObjectContext.selectFirst(Select)", because implementations of "Select" set fetch size limit to one.
    
    Specified by:
    
    selectFirst in interface Select<T>
  - iterate
```
public void iterate(ObjectContext context,
                    ResultIteratorCallback<T> callback)
```
    Description copied from interface: Select
    
    Creates a ResultIterator based on the provided context and passes it to a callback for processing. The caller does not need to worry about closing the iterator. This method takes care of it.
    Essentially the inversion of "ObjectContext.iterate(Select, ResultIteratorCallback)".
    
    Specified by:
    
    iterate in interface Select<T>
  - iterator
```
public ResultIterator<T> iterator(ObjectContext context)
```
    Description copied from interface: Select
    
    Creates a ResultIterator based on the provided context. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultIterator explicitly. Or use Select.iterate(ObjectContext, ResultIteratorCallback) as an alternative.
    Essentially the inversion of "ObjectContext.iterator(Select)".
    
    Specified by:
    
    iterator in interface Select<T>
  - batchIterator
```
public ResultBatchIterator<T> batchIterator(ObjectContext context,
                                            int size)
```
    Description copied from interface: Select
    
    Creates a ResultBatchIterator based on the provided context and batch size. It is usually backed by an open result set and is useful for processing of large data sets, preserving a constant memory footprint. The caller must wrap iteration in try/finally (or try-with-resources for Java 1.7 and higher) and close the ResultBatchIterator explicitly.
    
    Specified by:
    
    batchIterator in interface Select<T>
  - createReplacementQuery
```
protected Query createReplacementQuery(EntityResolver resolver)
```
    Description copied from class: IndirectQuery
    
    Creates a substitute query. An implementor is free to provide an arbitrary replacement query.
    
    Overrides:
    
    createReplacementQuery in class AbstractMappedQuery

Class MappedSelect<T>

Field Summary

Fields inherited from class org.apache.cayenne.query.AbstractMappedQuery

Fields inherited from class org.apache.cayenne.query.IndirectQuery

Constructor Summary

Method Summary

Methods inherited from class org.apache.cayenne.query.AbstractMappedQuery

Methods inherited from class org.apache.cayenne.query.IndirectQuery

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.cayenne.query.Query

Field Detail

resultClass

fetchLimit

fetchOffset

statementFetchSize

pageSize

forceNoCache

Constructor Detail

MappedSelect

MappedSelect

Method Detail

query

query

limit

offset

statementFetchSize

pageSize

forceNoCache

params

param

select

selectOne

selectFirst

iterate

iterator

batchIterator

createReplacementQuery