InstrumentationTest.java

package bob.yop;

import static net.bytebuddy.implementation.MethodDelegation.to;
import static net.bytebuddy.matcher.ElementMatchers.nameContains;
import static net.bytebuddy.matcher.ElementMatchers.named;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import org.apache.kafka.common.network.NetworkReceive;
import net.bytebuddy.agent.ByteBuddyAgent;
import net.bytebuddy.agent.builder.AgentBuilder;
import net.bytebuddy.implementation.SuperMethodCall;
import net.bytebuddy.implementation.bind.annotation.FieldValue;
import net.bytebuddy.implementation.bind.annotation.Origin;

public class InstrumentationTest {

    public static void initialize() {
        new AgentBuilder.Default()
                .type(named("bob.yop.InstrumentationTest$Foo").or(nameContains("NetworkReceive")))
                .transform((builder, typeDescription, classLoader) -> builder
                // cannot work because new Object() { ... } is not visible to NetworkReceive
//                        .constructor(any()).intercept(to(new Object() {
//                            public void construct(@AllArguments Object[] parameters, @Origin Class<?> type) throws Exception {
//                                System.out.format("%s.<cinit>%n", type.getSimpleName());
//                            }
//                        }).andThen(SuperMethodCall.INSTANCE))
                        .method(named("foo").or(named("complete")))
                        .intercept(to(ReadFieldOnMethod.class).andThen(SuperMethodCall.INSTANCE)))
                .installOn(ByteBuddyAgent.install());
    }

    public static void main(String[] args) {
        initialize();

        new NetworkReceive().complete();

        Foo foo = new Foo();
        System.out.println(foo.foo(1, 5));
    }

    private static class Foo {
        ByteBuffer size;

        public Foo() {
            this("a", 1);
        }

        public Foo(String a, int i) {
            size = ByteBuffer.allocate(4);
        }

        public int foo(int a, int b) {
            return a + b;
        }
    }

    public static class ReadFieldOnMethod {
        public static void logFieldValue(@Origin Method method, @FieldValue("size") ByteBuffer size) {
            System.out.format("'%s.%s', size=%d%n", method.getDeclaringClass().getSimpleName(), method.getName(), size.getInt());
            size.rewind();
        }
    }
}

part of the pom

        <dependency>
            <groupId>net.bytebuddy</groupId>
            <artifactId>byte-buddy-agent</artifactId>
            <version>1.4.14</version>
        </dependency>


            <dependency>
                <groupId>org.apache.kafka</groupId>
                <artifactId>kafka-clients</artifactId>
                <version>0.9.0.1</version>
            </dependency>