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Polish SpEL operator examples in reference docs

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Closes gh-36367

Signed-off-by: Tran Ngoc Nhan <ngocnhan.tran1996@gmail.com>
This commit is contained in:
Tran Ngoc Nhan
2026-02-23 17:08:22 +01:00
committed by Sam Brannen
parent 7299ff9326
commit 057633edb5
3 changed files with 89 additions and 33 deletions
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framework-docs/modules/ROOT/pages/core/expressions/language-ref/operators.adoc
+8 -33
View File
@@ -53,7 +53,7 @@ Kotlin::
val trueValue = parser.parseExpression("'black' < 'block'").getValue(Boolean::class.java)
// uses CustomValue:::compareTo
val trueValue = parser.parseExpression("new CustomValue(1) < new CustomValue(2)").getValue(Boolean::class.java);
val trueValue = parser.parseExpression("new CustomValue(1) < new CustomValue(2)").getValue(Boolean::class.java)
----
======
@@ -167,7 +167,7 @@ Kotlin::
[CAUTION]
====
The syntax for the `between` operator is `<input> between {<range_begin>, <range_end>}`,
which is effectively a shortcut for `<input> >= <range_begin> && <input> \<= <range_end>}`.
which is effectively a shortcut for `<input> >= <range_begin> && <input> \<= <range_end>`.
Consequently, `1 between {1, 5}` evaluates to `true`, while `1 between {5, 1}` evaluates
to `false`.
@@ -312,13 +312,13 @@ Kotlin::
// evaluates to 'a'
val ch = parser.parseExpression("'d' - 3")
.getValue(Character::class.java);
.getValue(Char::class.java)
// -- Repeat --
// evaluates to "abcabc"
val repeated = parser.parseExpression("'abc' * 2")
.getValue(String::class.java);
.getValue(String::class.java)
----
======
@@ -485,7 +485,7 @@ Kotlin::
// -- Operator precedence --
val minusTwentyOne = parser.parseExpression("1+2-3*8").getValue(Int::class.java) // -21
val minusTwentyOne = parser.parseExpression("1+2-3*8").getValue(Int::class.java) // -21
----
======
@@ -541,32 +541,7 @@ For example, if we want to overload the `ADD` operator to allow two lists to be
concatenated using the `+` sign, we can implement a custom `OperatorOverloader` as
follows.
[source,java,indent=0,subs="verbatim,quotes"]
----
pubic class ListConcatenation implements OperatorOverloader {
@Override
public boolean overridesOperation(Operation operation, Object left, Object right) {
return (operation == Operation.ADD &&
left instanceof List && right instanceof List);
}
@Override
@SuppressWarnings("unchecked")
public Object operate(Operation operation, Object left, Object right) {
if (operation == Operation.ADD &&
left instanceof List list1 && right instanceof List list2) {
List result = new ArrayList(list1);
result.addAll(list2);
return result;
}
throw new UnsupportedOperationException(
"No overload for operation %s and operands [%s] and [%s]"
.formatted(operation, left, right));
}
}
----
include-code::./ListConcatenation[]
If we register `ListConcatenation` as the `OperatorOverloader` in a
`StandardEvaluationContext`, we can then evaluate expressions like `{1, 2, 3} + {4, 5}`
@@ -589,8 +564,8 @@ Kotlin::
+
[source,kotlin,indent=0,subs="verbatim,quotes"]
----
StandardEvaluationContext context = StandardEvaluationContext()
context.setOperatorOverloader(ListConcatenation())
val context = StandardEvaluationContext()
context.operatorOverloader = ListConcatenation()
// evaluates to a new list: [1, 2, 3, 4, 5]
parser.parseExpression("{1, 2, 3} + {2 + 2, 5}").getValue(context, List::class.java)