matcher-generator v5.1.0

One annotation, GenerateMatchers, tells the processor which types to generate for. Put it on a class of your choice. The backends on the processor path both read it, so a configuration selects the same types for the Hamcrest matchers and the AssertJ assertions. The annotation has source retention: the processor reads it while compiling, and the compiled class of your configuration class carries no trace of it.

Selecting types

The annotation’s value lists package names and fully qualified class names. A package entry selects every class in the package, and a class entry selects exactly that class:

import io.github.marmer.matchergenerator.annotations.GenerateMatchers;

/** Generates a matcher for every model class in {@code example.hamcrest.model}. */
@GenerateMatchers("example.hamcrest.model")
public final class HamcrestConfiguration {}

This configuration generates a matcher for every model class in example.hamcrest.model. The model classes can be beans with getters, records or Kotlin classes: the processor reads bean getters, record component accessors and Kotlin getters.

Lombok-generated getters are read as well, provided the Lombok annotation processor runs before the generator. Put Lombok first on the processor path, as the Lombok end-to-end module hamcrest-matcher-generator-endtoend-lombok does, so that the generator sees the getters Lombok adds in the same compilation. That module is tested with the Lombok version of the project’s root pom.

Excluding types

The annotation’s exclude value takes the same kinds of entries and removes types from the selection. A package entry excludes every configured type in it, and a class entry excludes that one type. An entry that matches no configured type is reported as a warning, so a misspelled name does not pass silently.

Package of the generated types

The generation setting packageConfig decides the package of the generated types. Its value is a prefix, so the generated code of a type can live in a package other than the one of the type. The javadoc of the annotation gives the rule with examples: the prefix some.praefix. turns the package some.pck of some.pck.SomeType into some.praefix.some.pck, and an empty value keeps the package of the type.

Where the generated code goes

With Maven, the generated sources of a configuration in src/main/java go to target/generated-sources/annotations, and those of a configuration in src/test/java go to target/generated-test-sources/test-annotations. The example module’s own configuration is in src/main/java; the test-scope location was checked with a temporary test configuration in that module, not kept in the example. Because the example’s matchers are generated into the main output, they are available to test code as well as to production code.

Next steps