# IBM JDBC Driver — Wire Protocol Class Index

> **Phase 0 spike artifact.** Reverse-lookup index into the decompiled `com.ibm.informix:jdbc:4.50.4.1` JAR. This document tells us which Java class to read when we want to understand how the JDBC driver implements a given wire-protocol concern.
>
> **Legal note**: the decompiled source lives in `build/jdbc-src/` and is **not committed to this repository**. It is consulted as a clean-room understanding reference only. The Python implementation in `src/informix_db/` is written from `PROTOCOL_NOTES.md` (which cites observed packet bytes), not from the Java source.

## Decompilation

```bash
# Get the JAR
curl -O https://repo1.maven.org/maven2/com/ibm/informix/jdbc/4.50.4.1/jdbc-4.50.4.1.jar

# Decompile (CFR — https://www.benf.org/other/cfr/)
java -jar cfr.jar jdbc-4.50.4.1.jar --outputdir build/jdbc-src/
```

Driver version: `4.50.4.1` (latest as of 2026-05-02 on Maven Central).

## Top-level package layout

TBD — populate after decompilation.

Expected (from research):
- `com.informix.jdbc` — driver entry, connection, statement, result-set
- Likely subpackages for protocol I/O, type system, error mapping

## Class index (responsibility → class)

| Concern | Class | File path under `build/jdbc-src/` | Notes |
|---------|-------|------------------------------------|-------|
| Driver entry point         | `com.informix.jdbc.IfxDriver`     | TBD | implements `java.sql.Driver` |
| Connection                 | `com.informix.jdbc.IfxConnection` | TBD | extends `java.sql.Connection` |
| Wire socket I/O            | TBD | TBD | look for `DataOutputStream` / `DataInputStream` users |
| Message framing            | TBD | TBD | length-prefix + type-tag handlers |
| Login handshake            | TBD | TBD | username/password/database selection |
| Auth method dispatch       | TBD | TBD | plain / obfuscated / GSSAPI |
| Statement execute          | TBD | TBD | EXECUTE / EXECUTE IMMEDIATE entry points |
| Prepared statement         | TBD | TBD | parameter descriptors |
| Result-set parsing         | TBD | TBD | column descriptors + row decoding |
| Type codecs (encoders)     | TBD | TBD | `IfxTypeId` likely; per-type encoder methods |
| Type codecs (decoders)     | TBD | TBD | per-type decoder methods |
| Error decoding (SQLSTATE)  | TBD | TBD | error-message → SQLException mapping |
| Disconnection              | TBD | TBD | logout / socket close |
| Protocol trace             | `com.informix.jdbc.*.getProtoTrace` | TBD | Useful debug hook; understand what it logs |

## Method-level pointers

> As we identify specific methods that map to specific wire bytes, record them here. Format: `Class#method() → wire effect`.

- _(none yet)_

## Things to grep for

```bash
# Wire I/O entry points
grep -rln "DataOutputStream\|DataInputStream" build/jdbc-src/

# Type code constants
grep -rln "TYPEID\|IfxTypeId\|TypeId" build/jdbc-src/

# Auth method strings
grep -rln "OBFUSCATE\|PWDOBFUSCATION\|GSS\|KERBEROS" build/jdbc-src/

# SQLSTATE / error mapping
grep -rln "SQLSTATE\|SQLException" build/jdbc-src/
```