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Jul 24, 2025
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feat: implement cast, right, left, replace expressions #894

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1ccf936
feat: implement cast, right, left, replace expressions
cj848 Jul 5, 2025
bef6134
fix: apply reviews
cj848 Jul 18, 2025
77cb87f
fix: apply reviews
cj848 Jul 19, 2025
ff21748
fix: apply review
cj848 Jul 24, 2025
ae90af2
Merge branch 'develop' of https://github.com/cj848/kotlin-jdsl into f…
cj848 Jul 24, 2025
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16 changes: 16 additions & 0 deletions docs/en/jpql-with-kotlin-jdsl/expressions.md
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Expand Up @@ -199,6 +199,10 @@ Kotlin JDSL provides a series of functions to support built-in functions in JPA.
* UPPER (upper)
* LENGTH (length)
* LOCATE (locate)
* CAST (cast) - *Added in JPA 3.2*
* LEFT (left) - *Added in JPA 3.2*
* RIGHT (right) - *Added in JPA 3.2*
* REPLACE (replace) - *Added in JPA 3.2*

```kotlin
concat(path(Book::title), literal(":"), path(Book::imageUrl))
Expand All @@ -215,6 +219,18 @@ upper(path(Book::title))
length(path(Book::title))

locate("Book", path(Book::title))

cast(path(Book::price), String::class)
cast<String>(path(Book::price))

left(path(Book::title), 3)
left(path(Book::title), literal(3))

right(path(Book::title), 3)
right(path(Book::title), literal(3))

replace(path(Book::title), "old", "new")
replace(path(Book::title), literal("old"), literal("new"))
```

### Arithmetic functions
Expand Down
16 changes: 16 additions & 0 deletions docs/ko/jpql-with-kotlin-jdsl/expressions.md
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Expand Up @@ -197,6 +197,10 @@ Kotlin JDSL은 JPA에서 제공하는 여러 함수들을 지원하기 위한
* UPPER (upper)
* LENGTH (length)
* LOCATE (locate)
* CAST (cast) - *JPA 3.2에 추가됨*
* LEFT (left) - *JPA 3.2에 추가됨*
* RIGHT (right) - *JPA 3.2에 추가됨*
* REPLACE (replace) - *JPA 3.2에 추가됨*

```kotlin
concat(path(Book::title), literal(":"), path(Book::imageUrl))
Expand All @@ -213,6 +217,18 @@ upper(path(Book::title))
length(path(Book::title))

locate("Book", path(Book::title))

cast(path(Book::price), String::class)
cast<String>(path(Book::price))

left(path(Book::title), 3)
left(path(Book::title), literal(3))

right(path(Book::title), 3)
right(path(Book::title), literal(3))

replace(path(Book::title), "old", "new")
replace(path(Book::title), literal("old"), literal("new"))
```

### Arithmetic functions
Expand Down
72 changes: 72 additions & 0 deletions dsl/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/dsl/jpql/Jpql.kt
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Expand Up @@ -1705,6 +1705,78 @@ open class Jpql : JpqlDsl {
)
}

/**
* Creates an expression that represents the casting of a value to a different type.
*/
@SinceJdsl("3.6.0")
fun <T : Any> cast(value: Expressionable<*>, type: KClass<T>): Expression<T> {
return Expressions.cast(value.toExpression(), type)
}

/**
* Creates an expression that represents the casting of a value to a different type.
*/
@SinceJdsl("3.6.0")
inline fun <reified T : Any> cast(value: Expressionable<*>): Expression<T> {
return Expressions.cast(value.toExpression(), T::class)
}
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https://jakarta.ee/specifications/persistence/3.2/jakarta-persistence-spec-3.2#typecasts

string_cast_function::=
    CAST(scalar_expression AS STRING)
arithmetic_cast_function::=
    CAST(string_expression AS {INTEGER | LONG | FLOAT | DOUBLE})

Looking at the Jakarta specification, the range of castable types is limited depending on whether cast is a scalar type or a string type.

I believe this information should also be included in the function specification.

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And I think it would be best to create a function form that is as similar as possible to the JPQL specification.

Therefore, I think it would be good to create CastStep, similar to TrimFromStep. Creating CastStep would also make it easier to implement type restrictions.

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@cj848 cj848 Jul 19, 2025 •
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yeah. applied

Users can use the cast operator as follows:

cast(path(Book::price)).asString() // scalar expression as String
cast(path(Book::authorId)).asInt() // string expression as integer
cast(path(Book::authorId)).asLong() // string expression as long
cast(path(Book::authorId)).asDouble() // string expression as float
cast(path(Book::authorId)).asFloat() // string expression as double


/**
* Creates an expression that returns the leftmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun left(value: Expressionable<String>, count: Expressionable<Int>): Expression<String> {
return Expressions.left(value.toExpression(), count.toExpression())
}
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https://jakarta.ee/specifications/persistence/3.2/jakarta-persistence-spec-3.2#_criteriabuilder_

Expression<String> left(Expression<String> x, int len);
Expression<String> right(Expression<String> x, Expression<Integer> len);
Expression<String> replace(Expression<String> x, Expression<String> substring, Expression<String> replacement);

It would be best to follow the parameter naming conventions of CriteriaBuilder.
count should be length, and search should be substring.

The parameter name x is not ideal, so it would be best to use the value as is.

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thank you. your reviews applied


/**
* Creates an expression that returns the leftmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun left(value: Expressionable<String>, count: Int): Expression<String> {
return Expressions.left(value.toExpression(), intLiteral(count))
}

/**
* Creates an expression that returns the rightmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun right(value: Expressionable<String>, count: Expressionable<Int>): Expression<String> {
return Expressions.right(value.toExpression(), count.toExpression())
}

/**
* Creates an expression that returns the rightmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun right(value: Expressionable<String>, count: Int): Expression<String> {
return Expressions.right(value.toExpression(), intLiteral(count))
}

/**
* Creates an expression that replaces all occurrences of a search string with a replacement string.
*/
@SinceJdsl("3.6.0")
fun replace(
value: Expressionable<String>,
search: Expressionable<String>,
replacement: Expressionable<String>,
): Expression<String> {
return Expressions.replace(value.toExpression(), search.toExpression(), replacement.toExpression())
}

/**
* Creates an expression that replaces all occurrences of a search string with a replacement string.
*/
@SinceJdsl("3.6.0")
fun replace(
value: Expressionable<String>,
search: String,
replacement: String,
): Expression<String> {
return Expressions.replace(value.toExpression(), stringLiteral(search), stringLiteral(replacement))
}

/**
* Creates an expression that represents predefined database functions and user-defined database functions.
*/
Expand Down
154 changes: 154 additions & 0 deletions dsl/jpql/src/test/kotlin/com/linecorp/kotlinjdsl/dsl/jpql/expression/ExpressionDslTest.kt
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Expand Up @@ -44,4 +44,158 @@ class ExpressionDslTest : WithAssertions {

assertThat(actual).isEqualTo(expected)
}

@Test
fun `cast() with a expression and a class`() {
// when
val expression = queryPart {
cast(expression(String::class, alias1), Int::class)
}.toExpression()

val actual: Expression<Int> = expression // for type check

// then
val expected = Expressions.cast(
Expressions.expression(String::class, alias1),
Int::class,
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `inline cast() with a expression and a class`() {
// when
val expression = queryPart {
cast<Int>(expression(String::class, alias1))
}.toExpression()

val actual: Expression<Int> = expression // for type check

// then
val expected = Expressions.cast(
Expressions.expression(String::class, alias1),
Int::class,
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `left() with two expressions`() {
// when
val expression = queryPart {
left(expression(String::class, alias1), expression(Int::class, "alias2"))
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.left(
Expressions.expression(String::class, alias1),
Expressions.expression(Int::class, "alias2"),
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `left() literal with two expressions`() {
// when
val expression = queryPart {
left(expression(String::class, alias1), 1)
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.left(
Expressions.expression(String::class, alias1),
Expressions.intLiteral(1),
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `right() with two expressions`() {
// when
val expression = queryPart {
right(expression(String::class, alias1), expression(Int::class, "alias2"))
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.right(
Expressions.expression(String::class, alias1),
Expressions.expression(Int::class, "alias2"),
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `right() literal with two expressions`() {
// when
val expression = queryPart {
right(expression(String::class, alias1), 1)
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.right(
Expressions.expression(String::class, alias1),
Expressions.intLiteral(1),
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `replace() with three expressions`() {
// when
val expression = queryPart {
replace(
expression(String::class, alias1),
expression(String::class, "alias2"),
expression(String::class, "alias3"),
)
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.replace(
Expressions.expression(String::class, alias1),
Expressions.expression(String::class, "alias2"),
Expressions.expression(String::class, "alias3"),
)

assertThat(actual).isEqualTo(expected)
}

@Test
fun `replace() literal with three expressions`() {
// when
val expression = queryPart {
replace(
expression(String::class, alias1),
"string1",
"string2",
)
}.toExpression()

val actual: Expression<String> = expression // for type check

// then
val expected = Expressions.replace(
Expressions.expression(String::class, alias1),
Expressions.stringLiteral("string1"),
Expressions.stringLiteral("string2"),
)

assertThat(actual).isEqualTo(expected)
}
}
40 changes: 40 additions & 0 deletions ...el/jpql/src/main/kotlin/com/linecorp/kotlinjdsl/querymodel/jpql/expression/Expressions.kt
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Expand Up @@ -7,6 +7,7 @@ import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlAliasedExpres
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlAvg
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlCaseValue
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlCaseWhen
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlCast
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlCeiling
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlCoalesce
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlConcat
Expand All @@ -22,6 +23,7 @@ import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlExpression
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlExpressionParentheses
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlFloor
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlFunctionExpression
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlLeft
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlLength
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlLiteral
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlLn
Expand All @@ -41,6 +43,8 @@ import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlParam
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlPathType
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlPlus
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlPower
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlReplace
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlRight
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlRound
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlSign
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl.JpqlSize
Expand Down Expand Up @@ -723,6 +727,42 @@ object Expressions {
return JpqlLocate(substring, string, start)
}

/**
* Creates an expression that represents the casting of a value to a different type.
*/
@SinceJdsl("3.6.0")
fun <T : Any> cast(value: Expression<*>, type: KClass<T>): Expression<T> {
return JpqlCast(value, type)
}

/**
* Creates an expression that returns the leftmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun left(value: Expression<String>, count: Expression<Int>): Expression<String> {
return JpqlLeft(value, count)
}

/**
* Creates an expression that returns the rightmost count characters from a string.
*/
@SinceJdsl("3.6.0")
fun right(value: Expression<String>, count: Expression<Int>): Expression<String> {
return JpqlRight(value, count)
}

/**
* Creates an expression that replaces all occurrences of a search string with a replacement string.
*/
@SinceJdsl("3.6.0")
fun replace(
value: Expression<String>,
search: Expression<String>,
replacement: Expression<String>,
): Expression<String> {
return JpqlReplace(value, search, replacement)
}

/**
* Creates an expression that represents predefined database functions and user-defined database functions.
*/
Expand Down
11 changes: 11 additions & 0 deletions .../jpql/src/main/kotlin/com/linecorp/kotlinjdsl/querymodel/jpql/expression/impl/JpqlCast.kt
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@@ -0,0 +1,11 @@
package com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl

import com.linecorp.kotlinjdsl.SinceJdsl
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.Expression
import kotlin.reflect.KClass

@SinceJdsl("3.6.0")
data class JpqlCast<T : Any> internal constructor(
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Since it is implementation code, it would be good to include the internal annotation.

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thank you. your reviews applied

val value: Expression<*>,
val type: KClass<T>,
) : Expression<T>
10 changes: 10 additions & 0 deletions .../jpql/src/main/kotlin/com/linecorp/kotlinjdsl/querymodel/jpql/expression/impl/JpqlLeft.kt
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@@ -0,0 +1,10 @@
package com.linecorp.kotlinjdsl.querymodel.jpql.expression.impl

import com.linecorp.kotlinjdsl.SinceJdsl
import com.linecorp.kotlinjdsl.querymodel.jpql.expression.Expression

@SinceJdsl("3.6.0")
data class JpqlLeft internal constructor(
val value: Expression<String>,
val length: Expression<Int>,
) : Expression<String>
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