com.querydsl.core.types

Class MappingProjection<T>

java.lang.Object

com.querydsl.core.types.ExpressionBase<T>

com.querydsl.core.types.FactoryExpressionBase<T>

com.querydsl.core.types.MappingProjection<T>

Type Parameters:

T - expression type

All Implemented Interfaces:

Expression<T>, FactoryExpression<T>, Serializable

@Immutable
public abstract class MappingProjection<T>
extends FactoryExpressionBase<T>

Projection template that allows implementing arbitrary mapping of rows to result objects.

Example

  MappingProjection<Pair<String, String>> mapping = new  MappingProjection<Pair<String, String>>(Pair.class, str1, str2) {
      @Override
      protected Pair<String, String> map(Tuple row) {
          return Pair.of(row.get(str1), row.get(str2));
     }
 };
 

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MappingProjection(Class<? super T> type, Expression<?>... args) Create a new MappingProjection instance
MappingProjection(Class<? super T> type, Expression<?>[]... args) Create a new MappingProjection instance

Method Summary

Modifier and Type	Method and Description
<R,C> R	accept(Visitor<R,C> v, C context) Accept the visitor with the given context
List<Expression<?>>	getArgs() Get the invocation arguments
protected abstract T	map(Tuple row) Creates a result object from the given row.
T	newInstance(Object... values) Create a projection with the given arguments

Methods inherited from class com.querydsl.core.types.FactoryExpressionBase

equals, skipNulls

Methods inherited from class com.querydsl.core.types.ExpressionBase

getType, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.querydsl.core.types.Expression

getType

Constructor Detail

MappingProjection

public MappingProjection(Class<? super T> type,
                         Expression<?>... args)

Create a new MappingProjection instance

Parameters:

type -

args -

MappingProjection

public MappingProjection(Class<? super T> type,
                         Expression<?>[]... args)

Create a new MappingProjection instance

Parameters:

type -

args -

Method Detail

newInstance

public T newInstance(Object... values)

Description copied from interface: FactoryExpression

Create a projection with the given arguments

Parameters:

values - row arguments

Returns:

constructed value

map

protected abstract T map(Tuple row)

Creates a result object from the given row.

Parameters:

row - The row to map

Returns:

The result object

getArgs

public List<Expression<?>> getArgs()

Description copied from interface: FactoryExpression

Get the invocation arguments

Returns:

argument expressions

accept

public <R,C> R accept(Visitor<R,C> v,
                      @Nullable
                      C context)

Description copied from interface: Expression

Accept the visitor with the given context

Type Parameters:

R - return type

C - context type

Parameters:

v - visitor

context - context of visit

Returns:

result of visit