CAMEL-22894: Extract direct and misc function factories from SimpleFunctionExpression

[ammachado]

Description

Continues the refactoring started in CAMEL-22894 by extracting two more
groups of functions out of SimpleFunctionExpression into dedicated factory classes.

Refactoring

DirectFunctionFactory handles exact-match keyword functions that must be dispatched before OGNL prefix checks (id, exchangeId, exception, null, body, originalBody, etc.).

MiscFunctionFactory handles the remaining utility functions (isEmpty, isNumeric, isAlpha, not, convertTo, uuid, hash, iif, load, etc.).

SimpleFunctionExpression shrinks from ~1700 to ~1000 lines. The not() CSimple code-generation path is kept inline because it requires the skipFileFunctions flag from the enclosing parser context.

Tests

• 28 unit tests for DirectFunctionFactory (all keyword functions + createCode paths)
• 35 unit tests for MiscFunctionFactory (isEmpty, isAlpha, isNumeric, not, convertTo, uuid, hash, empty, iif, load + createCode variants)

Documentation fixes

Fix 15 errors found during an audit of simple-language.adoc:

• sysenv.key table entry: corrected "JVM system property" to "OS environment variable"
• Date function table: fix typo data:command -> date:command (two rows)
• isAlpha examples: add missing closing parentheses
• average prose: fix wrong function name ${avg()} -> ${average()}
• floor prose: replace copy-pasted ${ceil(...)} examples with ${floor(...)}
• sum prose: fix missing opening brace $sum(...) -> ${sum(...)}
• toPrettyJson: replace literal TODO: placeholder with actual output example
• XPath section: replace copy-pasted jsonpath() examples with xpath() expressions
• lowercase/uppercase examples: replace backtick with closing single quote
• pad examples: replace invalid single-argument form with correct two-argument form
• Chain operator example: fix -> to ~> on the last link
• AND/OR examples: remove spurious ' inside ${header.type'}
• Init block example: add missing ) in ${uppercase('Hello ${body}')}
• @BindToRegistry tip: close unclosed string literal
• Normalize JSon -> JSON throughout the document

Target

• I checked that the commit is targeting the correct branch (Camel 4 uses the main branch)

Tracking

• If this is a large change, bug fix, or code improvement, I checked there is a JIRA issue filed for the change (usually before you start working on it).

Apache Camel coding standards and style

• I checked that each commit in the pull request has a meaningful subject line and body.
• I have run mvn clean install -DskipTests locally from root folder and I have committed all auto-generated changes.

Claude Code on behalf of Adriano Machado

[github-actions]

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[github-actions]

🧪 CI tested the following changed modules:

• core/camel-core-languages
• core/camel-core

ℹ️ Dependent modules were not tested because the total number of affected modules exceeded the threshold (50). Use the test-dependents label to force testing all dependents.

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Build reactor — dependencies compiled but only changed modules were tested (2 modules)

• Camel :: Core
• Camel :: Core Languages

---

⚙️ View full build and test results

[davsclaus]

[05:04:22.454] WARN (asciidoctor): skipping reference to missing attribute: body
file: /home/runner/work/camel/camel/camel/docs/components/modules/languages/pages/simple-language.adoc
source: /home/runner/work/camel/camel/camel (branch: HEAD | start path: docs/components)
[05:04:22.457] WARN (asciidoctor): skipping reference to missing attribute: body
file: /home/runner/work/camel/camel/camel/docs/components/modules/languages/pages/simple-language.adoc
source: /home/runner/work/camel/camel/camel (branch: HEAD | start path: docs/components)
[05:04:22.458] WARN (asciidoctor): skipping reference to missing attribute: body
file: /home/runner/work/camel/camel/camel/docs/components/modules/languages/pages/simple-language.adoc
source: /home/runner/work/camel/camel/camel (branch: HEAD | start path: docs/components)

[gnodet]

Note: This diff exceeds 2000 lines. This review focuses on high-risk areas (core API, expression evaluation logic, test coverage).

Summary

This is a clean, well-structured continuation of the CAMEL-22894 refactoring. The extraction of DirectFunctionFactory and MiscFunctionFactory from SimpleFunctionExpression is mechanically correct -- I verified each function in both createFunction and createCode maps faithfully to the original logic.

What looks good

• No behavioral changes in the refactored code. The if-else chains, token-length checks, and error messages are preserved verbatim.
• not() code-gen correctly kept inline in SimpleFunctionExpression because it depends on skipFileFunctions from the parser context. Good call.
• routeGroup handled correctly: it was only in the expression path (not in createCode) in the original, and the PR preserves this.
• iif validation difference preserved: createFunction uses tokens.length > 3 while createCode uses tokens.length != 3 -- both matching the original.
• Good test coverage: 28 tests for DirectFunctionFactory (expression evaluation + code generation) and 35 tests for MiscFunctionFactory.
• Documentation fixes are all correct -- the typos (data->date, avg->average, ceil->floor, JSon->JSON, missing parens, wrong operators) are genuine fixes.

Issue: AsciiDoc build failure

The docs build is failing because of unescaped {body} attribute references in the pad function example. As @davsclaus pointed out, AsciiDoc interprets {body} as an attribute reference even inside backticks. The existing sum example on the line just above uses the proper $\{body} escape -- the pad example needs the same treatment. See the inline comment below.

Claude Code on behalf of Guillaume Nodet

[gnodet]

This line introduces unescaped ${body} references that AsciiDoc interprets as attribute lookups, causing the build failure @davsclaus flagged. The sum example just above (line 472) uses $\{body} to escape the braces -- the same pattern is needed here:

Suggested change

	If the message body contains `foo` then `${pad(${body},5)}` returns `"foo "` and `${pad(${body},-5)}` returns `" foo"`, and `${pad(${body},-5,'@')}` returns `@@foo`.
	If the message body contains `foo` then `${pad($\{body},5)}` returns `"foo "` and `${pad($\{body},-5)}` returns `" foo"`, and `${pad($\{body},-5,'@')}` returns `@@foo`.

Claude Code on behalf of Guillaume Nodet

[gnodet]

The AsciiDoc escaping issue is fixed -- pad() examples now use $\{body} correctly (commit d0d8372).

One minor observation on the docs/local-build.sh change: using "$*" joins all positional parameters into a single string, which changes behavior compared to the original $*. If the intent is to pass through multiple arguments, "$@" would be the standard choice. Not a blocker though; the script is rarely used and the rest of the PR is solid.

The overall refactoring and doc fixes look good. LGTM.

Claude Code on behalf of Guillaume Nodet