com.mysema.query.group
Class GroupBy<K,V>

java.lang.Object
  com.mysema.query.group.GroupBy<K,V>

All Implemented Interfaces:

ResultTransformer<Map<K,V>>

Direct Known Subclasses:

GroupByProjection

public class GroupBy<K,V>
extends Object
implements ResultTransformer<Map<K,V>>

Groups results by the first expression.

Author:

sasa, tiwe

Field Summary

protected Expression<?>[]	expressions
protected List<GroupExpression<?,?>>	groupExpressions
protected List<QPair<?,?>>	maps

Method Summary

static <E extends Number & Comparable<E>> AbstractGroupExpression<?,E>	avg(Expression<E> expression) Create a new aggregating avg expression
static <K> GroupByBuilder<K>	groupBy(Expression<K> key) Create a new GroupByBuilder for the given key expression
static <E> AbstractGroupExpression<?,List<E>>	list(Expression<E> expression) Create a new aggregating list expression
static <K,V> Expression<Map<K,V>>	map(Expression<K> key, Expression<V> value) Create a new aggregating map expression
static <E extends Comparable<E>> AbstractGroupExpression<?,E>	max(Expression<E> expression) Create a new aggregating max expression
static <E extends Comparable<E>> AbstractGroupExpression<?,E>	min(Expression<E> expression) Create a new aggregating min expression
static <E> AbstractGroupExpression<?,Set<E>>	set(Expression<E> expression) Create a new aggregating set expression
static <E extends Number & Comparable<E>> AbstractGroupExpression<?,E>	sum(Expression<E> expression) Create a new aggregating sum expression
protected Map<K,V>	transform(Map<K,Group> groups)
Map<K,V>	transform(Projectable projectable)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

groupExpressions

protected final List<GroupExpression<?,?>> groupExpressions

maps

protected final List<QPair<?,?>> maps

expressions

protected final Expression<?>[] expressions

Method Detail

groupBy

public static <K> GroupByBuilder<K> groupBy(Expression<K> key)

Create a new GroupByBuilder for the given key expression

Parameters:

key -

Returns:

min

public static <E extends Comparable<E>> AbstractGroupExpression<?,E> min(Expression<E> expression)

Create a new aggregating min expression

Parameters:

expression -

Returns:

sum

public static <E extends Number & Comparable<E>> AbstractGroupExpression<?,E> sum(Expression<E> expression)

Create a new aggregating sum expression

Parameters:

expression -

Returns:

avg

public static <E extends Number & Comparable<E>> AbstractGroupExpression<?,E> avg(Expression<E> expression)

Create a new aggregating avg expression

Parameters:

expression -

Returns:

max

public static <E extends Comparable<E>> AbstractGroupExpression<?,E> max(Expression<E> expression)

Create a new aggregating max expression

Parameters:

expression -

Returns:

list

public static <E> AbstractGroupExpression<?,List<E>> list(Expression<E> expression)

Create a new aggregating list expression

Parameters:

expression -

Returns:

set

public static <E> AbstractGroupExpression<?,Set<E>> set(Expression<E> expression)

Create a new aggregating set expression

Parameters:

expression -

Returns:

map

public static <K,V> Expression<Map<K,V>> map(Expression<K> key,
                                             Expression<V> value)

Create a new aggregating map expression

Parameters:

key -

value -

Returns:

transform

public Map<K,V> transform(Projectable projectable)

Specified by:

transform in interface ResultTransformer<Map<K,V>>

Returns:

transform

protected Map<K,V> transform(Map<K,Group> groups)