FastPathRouter/README.md

FastPathRouter (FPR)

FastPathRouter is a tiny, GC-friendly routing core designed to compile startup-time route definitions into immutable, array-based match tables. The hot path avoids String and Map allocations and works directly on byte views.

Modules:

• fpr-core: routing core and compiler
• fpr-netty: Netty adapters (ByteBuf view + path extraction)
• fpr-bench: JMH benchmarks

Philosophy:

• build routes at startup, compile into frozen tables
• match using byte-level comparisons
• avoid String/Map allocations in the hot path

Route syntax:

• params use {name} (e.g. /users/{id})
• mixed segments are allowed (e.g. /static/pre-{x}-suf)
• * matches a single segment, ** matches the rest of the path

Zero-copy param extraction:

RouterBuilder<String> builder = new RouterBuilder<>();
builder.add(StringRouteParser.parse("/users/{id}/orders/{orderId}"), "H");
FastPathRouter<ByteView, String> router = builder.compile();
String[] paramNames = builder.paramNames();

ByteView view = ...;
MatchResult<String> out = new MatchResult<>(builder.maxParamCount());
router.match(view, out);
out.forEachParam(view, paramNames, (name, bytes, start, len) -> {
    // Use bytes + start/len as needed; convert only if required.
});

Build and test:

mvn -q -DskipTests=false test

Run benchmarks:

mvn -pl fpr-bench -DskipTests package
java -jar fpr-bench/target/fpr-bench-1.0-SNAPSHOT-shaded.jar -wi 5 -i 5

Or use the Maven exec profile:

mvn -pl fpr-bench -am -Pbench verify