QueryFunction (com.holon-platform.core:holon-root 5.2.3 API)

Type Parameters:

T - Function result type

A - Function arguments type

All Superinterfaces:

Expression, QueryExpression<T>, QueryProjection<T>, TypedExpression<T>

All Known Subinterfaces:

QueryFunction.Avg, QueryFunction.Count, QueryFunction.Max<T>, QueryFunction.Min<T>, QueryFunction.NoArgQueryFunction<T>, QueryFunction.PropertyQueryFunction<T,A>, QueryFunction.Sum<T>, StringFunction, StringFunction.Lower, StringFunction.Upper, TemporalFunction<T>, TemporalFunction.CurrentDate, TemporalFunction.CurrentLocalDate, TemporalFunction.CurrentLocalDateTime, TemporalFunction.CurrentTimestamp, TemporalFunction.Day, TemporalFunction.Hour, TemporalFunction.Month, TemporalFunction.Year
```
public interface QueryFunction<T,A>
extends QueryExpression<T>, QueryProjection<T>
```
Represents a function expression. A function can be used as QueryProjection too.

Since:

5.0.0

Nested Class Summary

Nested Classes
Modifier and Type	Interface and Description
`static interface`	`QueryFunction.Avg` A function which represents the average value of a query result.
`static interface`	`QueryFunction.Count` A function which represents the count of a query result values.
`static interface`	`QueryFunction.Max<T>` A function which represents the largest value of a query result.
`static interface`	`QueryFunction.Min<T>` A function which represents the smallest value of a query result.
`static interface`	`QueryFunction.NoArgQueryFunction<T>` A `QueryFunction` which do not support any argument.
`static interface`	`QueryFunction.PropertyQueryFunction<T,A>` A `QueryFunction` which is also a `Property`, allowing the function to be used within a property set query projection and the function value to be collected in a `PropertyBox`.
`static interface`	`QueryFunction.Sum<T extends Number>` A function which represents the sum of a numeric query result values.

Nested classes/interfaces inherited from interface com.holonplatform.core.Expression
Expression.ExpressionResolverFunction<E extends Expression,R extends Expression>, Expression.InvalidExpressionException

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`static QueryFunction.Avg`	`avg(TypedExpression<? extends Number> argument)` Creates an aggregate function to calculate the average value of a numeric query result.
`static QueryFunction.Count`	`count(TypedExpression<?> argument)` Creates an aggregate function to count query results.
`static TemporalFunction.CurrentDate`	`currentDate()` Create a `TemporalFunction.CurrentDate` function to obtain the current date as a `Date`.
`static TemporalFunction.CurrentLocalDate`	`currentLocalDate()` Create a `TemporalFunction.CurrentLocalDate` function to obtain the current date as a `LocalDate`.
`static TemporalFunction.CurrentLocalDateTime`	`currentLocalDateTime()` Create a `TemporalFunction.CurrentLocalDateTime` function to obtain the current date and time as a `LocalDateTime`.
`static TemporalFunction.CurrentTimestamp`	`currentTimestamp()` Create a `TemporalFunction.CurrentTimestamp` function to obtain the current timestamp as a `Date`.
`static TemporalFunction.Day`	`day(TypedExpression<?> argument)` Create a function to extract the day part of a temporal data type.
`List<TypedExpression<? extends A>>`	`getExpressionArguments()` If the function supports expression arguments, returns the arguments list.
`static TemporalFunction.Hour`	`hour(TypedExpression<?> argument)` Create a function to extract the hour part of a temporal data type.
`static StringFunction.Lower`	`lower(TypedExpression<String> argument)` Creates a function to convert a String data type into lowercase.
`static <T> QueryFunction.Max<T>`	`max(TypedExpression<T> argument)` Creates an aggregate function to get the largest value of a query result.
`static <T> QueryFunction.Min<T>`	`min(TypedExpression<T> argument)` Creates an aggregate function to get the smallest value of a query result.
`static TemporalFunction.Month`	`month(TypedExpression<?> argument)` Create a function to extract the month part of a temporal data type.
`static <T extends Number> QueryFunction.Sum<T>`	`sum(TypedExpression<T> argument)` Creates an aggregate function to sum numeric query results.
`static StringFunction.Upper`	`upper(TypedExpression<String> argument)` Creates a function to convert a String data type into uppercase.
`static TemporalFunction.Year`	`year(TypedExpression<?> argument)` Create a function to extract the year part of a temporal data type.

Methods inherited from interface com.holonplatform.core.query.QueryExpression
between, count, eq, eq, goe, goe, gt, gt, in, in, in, isNotNull, isNull, loe, loe, lt, lt, max, min, neq, neq, nin, nin, nin

Methods inherited from interface com.holonplatform.core.query.QueryProjection
bean, constant, countAll, path, propertySet, propertySet

Methods inherited from interface com.holonplatform.core.TypedExpression
getTemporalType, getType, isCollectionExpression, isConverterExpression

Methods inherited from interface com.holonplatform.core.Expression
validate

- Method Detail
  - getExpressionArguments
```
List<TypedExpression<? extends A>> getExpressionArguments()
```
    If the function supports expression arguments, returns the arguments list.
    
    Returns:
    
    Function arguments, an empty list if none
  - count
```
static QueryFunction.Count count(TypedExpression<?> argument)
```
    Creates an aggregate function to count query results.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new QueryFunction.Count function
  - avg
```
static QueryFunction.Avg avg(TypedExpression<? extends Number> argument)
```
    Creates an aggregate function to calculate the average value of a numeric query result.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new QueryFunction.Avg function
  - min
```
static <T> QueryFunction.Min<T> min(TypedExpression<T> argument)
```
    Creates an aggregate function to get the smallest value of a query result.
    
    Type Parameters:
    
    T - Result type
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new QueryFunction.Min function
  - max
```
static <T> QueryFunction.Max<T> max(TypedExpression<T> argument)
```
    Creates an aggregate function to get the largest value of a query result.
    
    Type Parameters:
    
    T - Result type
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new QueryFunction.Max function
  - sum
```
static <T extends Number> QueryFunction.Sum<T> sum(TypedExpression<T> argument)
```
    Creates an aggregate function to sum numeric query results.
    
    Type Parameters:
    
    T - Result type
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new QueryFunction.Sum function
  - lower
```
static StringFunction.Lower lower(TypedExpression<String> argument)
```
    Creates a function to convert a String data type into lowercase.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new StringFunction.Lower function
  - upper
```
static StringFunction.Upper upper(TypedExpression<String> argument)
```
    Creates a function to convert a String data type into uppercase.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A new StringFunction.Lower function
  - currentDate
```
static TemporalFunction.CurrentDate currentDate()
```
    Create a TemporalFunction.CurrentDate function to obtain the current date as a Date.
    
    Returns:
    
    A function expression to obtain the current date as a Date.
  - currentLocalDate
```
static TemporalFunction.CurrentLocalDate currentLocalDate()
```
    Create a TemporalFunction.CurrentLocalDate function to obtain the current date as a LocalDate.
    
    Returns:
    
    A function expression to obtain the current date as a LocalDate.
  - currentTimestamp
```
static TemporalFunction.CurrentTimestamp currentTimestamp()
```
    Create a TemporalFunction.CurrentTimestamp function to obtain the current timestamp as a Date.
    
    Returns:
    
    A function expression to obtain the current timestamp
  - currentLocalDateTime
```
static TemporalFunction.CurrentLocalDateTime currentLocalDateTime()
```
    Create a TemporalFunction.CurrentLocalDateTime function to obtain the current date and time as a LocalDateTime.
    
    Returns:
    
    A function expression to obtain the current date and time as a LocalDateTime.
  - year
```
static TemporalFunction.Year year(TypedExpression<?> argument)
```
    Create a function to extract the year part of a temporal data type.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A function to extract the year part of a temporal data type.
  - month
```
static TemporalFunction.Month month(TypedExpression<?> argument)
```
    Create a function to extract the month part of a temporal data type.
    The month range index is between 1 and 12.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A function to extract the month part of a temporal data type.
  - day
```
static TemporalFunction.Day day(TypedExpression<?> argument)
```
    Create a function to extract the day part of a temporal data type.
    The day is intended as the day of month and the day range index is between 1 and 31.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A function to extract the day part of a temporal data type.
  - hour
```
static TemporalFunction.Hour hour(TypedExpression<?> argument)
```
    Create a function to extract the hour part of a temporal data type.
    The 24-hour clock is used and the hour range index is between 0 and 23.
    
    Parameters:
    
    argument - Function argument (not null)
    
    Returns:
    
    A function to extract the hour part of a temporal data type.

Interface QueryFunction<T,A>

Nested Class Summary

Nested classes/interfaces inherited from interface com.holonplatform.core.Expression

Method Summary

Methods inherited from interface com.holonplatform.core.query.QueryExpression

Methods inherited from interface com.holonplatform.core.query.QueryProjection

Methods inherited from interface com.holonplatform.core.TypedExpression

Methods inherited from interface com.holonplatform.core.Expression

Method Detail

getExpressionArguments

count

avg

min

max

sum

lower

upper

currentDate

currentLocalDate

currentTimestamp

currentLocalDateTime

year

month

day

hour