io.smallrye.mutiny.vertx.codegen.lang.IterableMethodCodeWriter Maven / Gradle / Ivy

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package io.smallrye.mutiny.vertx.codegen.lang;

import java.io.PrintWriter;

import io.vertx.codegen.ClassModel;
import io.vertx.codegen.type.ClassKind;
import io.vertx.codegen.type.TypeInfo;

/**
 * Add methods if the class implements {@code Iterable}, so the {@code iterator} method and the {@code toMulti} method.
 */
public class IterableMethodCodeWriter implements ConditionalCodeWriter {

    @Override
    public void generate(ClassModel model, PrintWriter writer) {
        TypeInfo iterableArg = model.getIterableArg();

        if (model.getMethods().stream().noneMatch(it -> it.getParams().isEmpty() && "iterator".equals(it.getName()))) {
            writer.println("  @Override");
            writer.printf("  public java.util.Iterator<%s> iterator() {%n", genTypeName(iterableArg));

            if (iterableArg.getKind() == ClassKind.API) {
                writer.format("    java.util.function.Function<%s, %s> conv = %s::newInstance;%n",
                        iterableArg.getName(),
                        genTypeName(iterableArg.getRaw()), genTypeName(iterableArg));
                writer.println(
                        "    return new io.smallrye.mutiny.vertx.impl.MappingIterator<>(delegate.iterator(), conv);");
            } else if (iterableArg.isVariable()) {
                String typeVar = iterableArg.getSimpleName();
                writer.format(
                        "    java.util.function.Function<%s, %s> conv = (java.util.function.Function<%s, %s>) __typeArg_0.wrap;%n",
                        typeVar, typeVar, typeVar, typeVar);
                writer.println(
                        "    return new io.smallrye.mutiny.vertx.impl.MappingIterator<>(delegate.iterator(), conv);");
            } else {
                writer.println("    return delegate.iterator();");
            }

            writer.println("  }");
            writer.println();
        }

        // Generate the toMulti method if not present
        if (model.getMethods().stream().noneMatch(it -> it.getParams().isEmpty() && "toMulti".equals(it.getName()))) {
            writer.print("  @CheckReturnValue\n");
            writer.printf("  public Multi<%s> toMulti() {%n", genTypeName(iterableArg));
            writer.println("    return Multi.createFrom().iterable(this);");
            writer.println("  }");
            writer.println();
        }
    }

    @Override
    public boolean test(ClassModel model) {
        return model.isConcrete() && model.isIterable();
    }
}