Package com.onec.query

Class Q

java.lang.Object

com.onec.query.Q

public final class Q
extends Object

Static factory helpers for the fluent query DSL. They mirror the col(...) / ref(...) / eq(...) shape from the issue and reuse the existing FieldReference method-reference mechanism for field resolution.

Paths produced here are left un-rooted; QueryEngine.from(Class) binds them to the query root, so Q.col(SalesOrder::getNumber) works without repeating the class.

 import static com.onec.query.Q.*;

 query.from(SalesOrder.class)
      .select(col(SalesOrder::getNumber),
              ref(SalesOrder::getCustomer, Customer::getName),
              ref(SalesOrder::getCustomer, Customer::getRegion, Region::getDescription))
      .where(eq(SalesOrder::getStatus, "APPROVED"))
      .orderBy(desc(SalesOrder::getDate))
      .fetch();
 

Method Summary

Modifier and Type	Method	Description
static Select	as(Select item, String alias)	Give a select item an explicit output alias (result-Row key / DTO property).
static Order	asc(Path path)
static <T, R> Order	asc(FieldReference<T,R> field)
static <T, R> Path	attr(FieldReference<T,R> field)	A single-attribute path, e.g.
static <T, R> Select	avg(FieldReference<T,R> field)
static Predicate	between(Path path, Object low, Object high)
static <T, R> Predicate	between(FieldReference<T,R> field, R low, R high)
static <T, R> Select	col(FieldReference<T,R> field)	Project a direct attribute.
static Select	count()
static <T, R> Select	count(FieldReference<T,R> field)
static Order	desc(Path path)
static <T, R> Order	desc(FieldReference<T,R> field)
static Predicate	eq(Path path, Object value)
static <T, R> Predicate	eq(FieldReference<T,R> field, R value)
static <T, R> Predicate	gt(FieldReference<T,R> field, R value)
static <T, R> Predicate	gte(FieldReference<T,R> field, R value)
static <T, R> Predicate	in(FieldReference<T,R> field, List<? extends R> values)
static <T, R> Predicate	isNotNull(FieldReference<T,R> field)
static <T, R> Predicate	isNull(FieldReference<T,R> field)
static <T> Predicate	like(FieldReference<T,String> field, String pattern)
static <T, R> Predicate	lt(FieldReference<T,R> field, R value)
static <T, R> Predicate	lte(FieldReference<T,R> field, R value)
static <T, R> Select	max(FieldReference<T,R> field)
static <T, R> Select	min(FieldReference<T,R> field)
static <T, A, B, R> Path	nav(FieldReference<T,Ref<A>> hop1, FieldReference<A,Ref<B>> hop2, FieldReference<B,R> terminal)	Two Ref hops ending in an attribute: customer -> region -> name.
static <T, A, R> Path	nav(FieldReference<T,Ref<A>> hop, FieldReference<A,R> terminal)	A single Ref hop ending in an attribute: customer -> name.
static Predicate	ne(Path path, Object value)
static <T, R> Predicate	ne(FieldReference<T,R> field, R value)
static <T, A, B, R> Select	ref(FieldReference<T,Ref<A>> hop1, FieldReference<A,Ref<B>> hop2, FieldReference<B,R> terminal)	Project a column reached through two Ref hops (auto-join, deep navigation).
static <T, A, R> Select	ref(FieldReference<T,Ref<A>> hop, FieldReference<A,R> terminal)	Project a column reached through one Ref hop (auto-join).
static Select	select(Path path)	Project an arbitrary path (direct or navigation).
static <T, R> Select	sum(FieldReference<T,R> field)

Methods inherited from class java.lang.Object

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

Method Details

attr

public static <T,
R> Path attr(FieldReference<T,R> field)

A single-attribute path, e.g. attr(SalesOrder::getNumber).

nav

public static <T,
A,
R> Path nav(FieldReference<T,Ref<A>> hop,
 FieldReference<A,R> terminal)

A single Ref hop ending in an attribute: customer -> name.

nav

public static <T,
A,
B,
R> Path nav(FieldReference<T,Ref<A>> hop1,
 FieldReference<A,Ref<B>> hop2,
 FieldReference<B,R> terminal)

Two Ref hops ending in an attribute: customer -> region -> name.

col

public static <T,
R> Select col(FieldReference<T,R> field)

Project a direct attribute.

ref

public static <T,
A,
R> Select ref(FieldReference<T,Ref<A>> hop,
 FieldReference<A,R> terminal)

Project a column reached through one Ref hop (auto-join).

ref

public static <T,
A,
B,
R> Select ref(FieldReference<T,Ref<A>> hop1,
 FieldReference<A,Ref<B>> hop2,
 FieldReference<B,R> terminal)

Project a column reached through two Ref hops (auto-join, deep navigation).

select

public static Select select(Path path)

Project an arbitrary path (direct or navigation).

count

public static Select count()

count

public static <T,
R> Select count(FieldReference<T,R> field)

sum

public static <T,
R> Select sum(FieldReference<T,R> field)

avg

public static <T,
R> Select avg(FieldReference<T,R> field)

min

public static <T,
R> Select min(FieldReference<T,R> field)

max

public static <T,
R> Select max(FieldReference<T,R> field)

as

public static Select as(Select item,
 String alias)

Give a select item an explicit output alias (result-Row key / DTO property).

eq

public static <T,
R> Predicate eq(FieldReference<T,R> field,
 R value)

ne

public static <T,
R> Predicate ne(FieldReference<T,R> field,
 R value)

gt

public static <T,
R> Predicate gt(FieldReference<T,R> field,
 R value)

gte

public static <T,
R> Predicate gte(FieldReference<T,R> field,
 R value)

lt

public static <T,
R> Predicate lt(FieldReference<T,R> field,
 R value)

lte

public static <T,
R> Predicate lte(FieldReference<T,R> field,
 R value)

between

public static <T,
R> Predicate between(FieldReference<T,R> field,
 R low,
 R high)

like

public static <T> Predicate like(FieldReference<T,String> field,
 String pattern)

in

public static <T,
R> Predicate in(FieldReference<T,R> field,
 List<? extends R> values)

isNull

public static <T,
R> Predicate isNull(FieldReference<T,R> field)

isNotNull

public static <T,
R> Predicate isNotNull(FieldReference<T,R> field)

eq

public static Predicate eq(Path path,
 Object value)

ne

public static Predicate ne(Path path,
 Object value)

between

public static Predicate between(Path path,
 Object low,
 Object high)

asc

public static <T,
R> Order asc(FieldReference<T,R> field)

desc

public static <T,
R> Order desc(FieldReference<T,R> field)

asc

public static Order asc(Path path)

desc

public static Order desc(Path path)