luchunliang opened a new pull request, #12214:
URL: https://github.com/apache/inlong/pull/12214
Fixes #12213
### Motivation
<!--Explain here the context, and why you're making that change. What is the
problem you're trying to solve.-->
### Modifications
### Proposed Change
Introduce a `NullValueParser` following the existing `StringParser` pattern:
```java
@TransformParser(values = NullValue.class)
public class NullValueParser implements ValueParser {
public NullValueParser(NullValue expr) {
// The NULL literal carries no value; nothing to store.
}
@Override
public Object parse(SourceData sourceData, int rowIndex, Context
context) {
return null;
}
}
```
`@TransformParser(values = NullValue.class)` registers `NullValue.class` in
`parserMap`, so `getTransformParser` resolves it through the reflective
constructor branch, and `NULL` literals evaluate to constant `null`.
### Resulting Behavior
- `ifnull(null, numeric2)` evaluates its first argument to `null`, so
`IfNullFunction` falls back to the second argument as expected.
- Other functions that receive a `NULL` literal as an argument (e.g.
`coalesce`, `num_nulls`, `concat_ws`) no longer fail during parser construction.
### Tests
Added a true-`NULL`-literal case to `TestIfNullFunction`:
```java
// case6: ifnull(null, numeric2) -- true NULL literal
transformSql = "select ifnull(null,numeric2) from source";
data = "5|3|3|5";
Assert.assertEquals("result=3", output.get(0));
```
Verified: `Tests run: 1, Failures: 0, Errors: 0, Skipped: 0`.
### Backward Compatibility
- Fully backward compatible.
- No public API or method-signature change; only a new parser class is added.
- Existing column / function / literal parsers are unaffected.
### Files Changed
-
`inlong-sdk/transform-sdk/src/main/java/org/apache/inlong/sdk/transform/process/parser/NullValueParser.java`
*(new)*
-
`inlong-sdk/transform-sdk/src/test/java/org/apache/inlong/sdk/transform/process/function/condition/TestIfNullFunction.java`
### Verifying this change
*(Please pick either of the following options)*
- [ ] This change is a trivial rework/code cleanup without any test coverage.
- [ ] This change is already covered by existing tests, such as:
*(please describe tests)*
- [ ] This change added tests and can be verified as follows:
*(example:)*
- *Added integration tests for end-to-end deployment with large payloads
(10MB)*
- *Extended integration test for recovery after broker failure*
### Documentation
- Does this pull request introduce a new feature? (yes / no)
- If yes, how is the feature documented? (not applicable / docs / JavaDocs
/ not documented)
- If a feature is not applicable for documentation, explain why?
- If a feature is not documented yet in this PR, please create a follow-up
issue for adding the documentation
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