Домашняя работа №11 (#15)

* Done homework 11

* Fixes homework 11

* Fix jacoco problem

* Fix jacoco problem

pom.xml

@@ -44,6 +44,8 @@
         <maven-site-plugin.version>4.0.0-M9</maven-site-plugin.version>
 
         <jacoco-maven-plugin.version>0.8.10</jacoco-maven-plugin.version>
+        <bytebuddy.version>1.14.9</bytebuddy.version>
+        <asm.version>9.6</asm.version>
     </properties>
 
     <dependencyManagement>
@@ -63,17 +65,26 @@
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
-
-            <!-- For resolve assertJ`s and mockito`s byte-buddy version conflict -->
-            <dependency>
-                <groupId>net.bytebuddy</groupId>
-                <artifactId>byte-buddy</artifactId>
-                <version>1.14.9</version>
-            </dependency>
         </dependencies>
     </dependencyManagement>
 
     <dependencies>
+        <dependency>
+            <groupId>org.ow2.asm</groupId>
+            <artifactId>asm</artifactId>
+            <version>${asm.version}</version>
+        </dependency>
+
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy-agent</artifactId>
+            <version>${bytebuddy.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>net.bytebuddy</groupId>
+            <artifactId>byte-buddy</artifactId>
+            <version>${bytebuddy.version}</version>
+        </dependency>
         <dependency>
             <groupId>org.jetbrains</groupId>
             <artifactId>annotations</artifactId>
@@ -198,6 +209,14 @@
                             </goals>
                         </execution>
                     </executions>
+                    <configuration>
+                        <excludes>
+                            <!--  Resolve problem with compatibility bytebuddy and jacoco -->
+                            <!--  Without this statement crash with exception. Primitive solving problem -->
+                            <!--  More: https://github.com/raphw/byte-buddy/issues/1248 -->
+                            <exclude>*ArithmeticUtils*</exclude>
+                        </excludes>
+                    </configuration>
                 </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>

src/main/java/edu/hw11/task1/HelloWorldCreator.java

@@ -0,0 +1,25 @@
+package edu.hw11.task1;
+
+import net.bytebuddy.ByteBuddy;
+import net.bytebuddy.implementation.FixedValue;
+import net.bytebuddy.matcher.ElementMatchers;
+
+public final class HelloWorldCreator {
+
+    private HelloWorldCreator() {
+    }
+
+    public static Object createHelloWorld() {
+        try (var unloaded = new ByteBuddy()
+            .subclass(Object.class)
+            .method(ElementMatchers.isToString())
+            .intercept(FixedValue.value("Hello, ByteBuddy!"))
+            .make()
+        ) {
+            return unloaded.load(HelloWorldCreator.class.getClassLoader()).getLoaded().getConstructor().newInstance();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+}

src/main/java/edu/hw11/task2/ArithmeticUtils.java

@@ -0,0 +1,10 @@
+package edu.hw11.task2;
+
+public final class ArithmeticUtils {
+    private ArithmeticUtils() {
+    }
+
+    public static int sum(int a, int b) {
+        return a + b;
+    }
+}

src/main/java/edu/hw11/task2/ClassBehaviourReloader.java

@@ -0,0 +1,31 @@
+package edu.hw11.task2;
+
+import net.bytebuddy.ByteBuddy;
+import net.bytebuddy.dynamic.loading.ClassReloadingStrategy;
+import net.bytebuddy.implementation.MethodDelegation;
+import net.bytebuddy.matcher.ElementMatchers;
+
+public final class ClassBehaviourReloader {
+
+    private ClassBehaviourReloader() {
+    }
+
+    /**
+     * Should be called after installing the agent {@link net.bytebuddy.agent.ByteBuddyAgent ByteBuddyAgent}
+     */
+    public static void reload() {
+        new ByteBuddy()
+            .redefine(ArithmeticUtils.class)
+            .method(ElementMatchers.named("sum"))
+            .intercept(MethodDelegation.to(Delegate.class))
+            .make()
+            .load(ArithmeticUtils.class.getClassLoader(), ClassReloadingStrategy.fromInstalledAgent());
+    }
+
+    private final static class Delegate {
+        public static int sum(int a, int b) {
+            return a * b;
+        }
+    }
+
+}

src/main/java/edu/hw11/task3/FibClassGenerator.java

@@ -0,0 +1,99 @@
+package edu.hw11.task3;
+
+import net.bytebuddy.ByteBuddy;
+import net.bytebuddy.description.method.MethodDescription;
+import net.bytebuddy.description.modifier.Ownership;
+import net.bytebuddy.description.modifier.Visibility;
+import net.bytebuddy.implementation.Implementation;
+import net.bytebuddy.implementation.bytecode.ByteCodeAppender;
+import net.bytebuddy.jar.asm.Label;
+import net.bytebuddy.jar.asm.MethodVisitor;
+import net.bytebuddy.jar.asm.Opcodes;
+import org.jetbrains.annotations.NotNull;
+
+public final class FibClassGenerator {
+
+    private static final String FIB_CLASS_NAME = "Fibonacci";
+    private static final String FUNCTION_NAME = "fib";
+    private static final int FUNCTION_OPERANDS_STACK_SIZE = 5;
+    private static final String FUNCTION_SIGNATURE = "(I)J";
+
+    private FibClassGenerator() {
+    }
+
+    public static Object generate() {
+        try (var unloaded = new ByteBuddy()
+            .subclass(Object.class)
+            .name(FIB_CLASS_NAME)
+            .defineMethod(FUNCTION_NAME, long.class, Ownership.MEMBER, Visibility.PUBLIC)
+            .withParameter(int.class, "n")
+            .intercept(createFibImplementation())
+            .make()
+        ) {
+            return unloaded.load(FibClassGenerator.class.getClassLoader()).getLoaded().getConstructor().newInstance();
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private static Implementation createFibImplementation() {
+        return new Implementation.Simple(new FibByteCodeAppender());
+    }
+
+    private final static class FibByteCodeAppender implements ByteCodeAppender {
+
+        @Override
+        @NotNull
+        public Size apply(
+            MethodVisitor methodVisitor,
+            @NotNull Implementation.Context context,
+            @NotNull MethodDescription methodDescription
+        ) {
+            Label moreTwoLabel = new Label();
+
+            methodVisitor.visitVarInsn(Opcodes.ILOAD, 1);
+            methodVisitor.visitInsn(Opcodes.ICONST_2);
+            methodVisitor.visitJumpInsn(Opcodes.IF_ICMPGE, moreTwoLabel);
+            methodVisitor.visitVarInsn(Opcodes.ILOAD, 1);
+            methodVisitor.visitInsn(Opcodes.I2L);
+            methodVisitor.visitInsn(Opcodes.LRETURN);
+
+            // more than 2
+            methodVisitor.visitLabel(moreTwoLabel);
+            methodVisitor.visitFrame(Opcodes.F_SAME, 0, null, 0, null);
+            methodVisitor.visitVarInsn(Opcodes.ALOAD, 0);
+            methodVisitor.visitVarInsn(Opcodes.ILOAD, 1);
+            methodVisitor.visitInsn(Opcodes.ICONST_1);
+            methodVisitor.visitInsn(Opcodes.ISUB);
+
+            // fib(n - 1)
+            methodVisitor.visitMethodInsn(
+                Opcodes.INVOKEVIRTUAL,
+                FIB_CLASS_NAME,
+                FUNCTION_NAME,
+                FUNCTION_SIGNATURE,
+                false
+            );
+
+            methodVisitor.visitVarInsn(Opcodes.ALOAD, 0);
+            methodVisitor.visitVarInsn(Opcodes.ILOAD, 1);
+            methodVisitor.visitInsn(Opcodes.ICONST_2);
+            methodVisitor.visitInsn(Opcodes.ISUB);
+
+            // fib(n - 2)
+            methodVisitor.visitMethodInsn(
+                Opcodes.INVOKEVIRTUAL,
+                FIB_CLASS_NAME,
+                FUNCTION_NAME,
+                FUNCTION_SIGNATURE,
+                false
+            );
+            methodVisitor.visitInsn(Opcodes.LADD);
+            methodVisitor.visitInsn(Opcodes.LRETURN);
+            // localVariableSize = 0 because Implementation.Simple creates variables
+            // for parameters and I don`t use anything else
+            return new ByteCodeAppender.Size(FUNCTION_OPERANDS_STACK_SIZE, 0);
+        }
+    }
+
+}

src/test/java/edu/hw11/task1/HelloWorldCreatorTest.java

@@ -0,0 +1,15 @@
+package edu.hw11.task1;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class HelloWorldCreatorTest {
+
+    @Test
+    @DisplayName("Тестирование HelloWorldCreator#createHelloWorld")
+    public void createHelloWorld_shouldReturnObjectReturnsHelloWorld() {
+        var helloWorld = HelloWorldCreator.createHelloWorld();
+        Assertions.assertThat(helloWorld.toString()).isEqualTo("Hello, ByteBuddy!");
+    }
+}

src/test/java/edu/hw11/task2/ClassBehaviourReloaderTest.java

@@ -0,0 +1,18 @@
+package edu.hw11.task2;
+
+import net.bytebuddy.agent.ByteBuddyAgent;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class ClassBehaviourReloaderTest {
+
+    @Test
+    @DisplayName("Тестирование ClassBehaviourReloader#reload")
+    public void reload() {
+        ByteBuddyAgent.install();
+        ClassBehaviourReloader.reload();
+        Assertions.assertThat(ArithmeticUtils.sum(5, 5)).isEqualTo(25);
+    }
+
+}

src/test/java/edu/hw11/task3/FibClassGeneratorTest.java

@@ -0,0 +1,20 @@
+package edu.hw11.task3;
+
+import java.lang.reflect.Method;
+import lombok.SneakyThrows;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+public class FibClassGeneratorTest {
+
+    @SneakyThrows @Test
+    @DisplayName("Тестирование FibClassGenerator#generate")
+    public void generate() {
+        Object object = FibClassGenerator.generate();
+        Class<?> clazz = object.getClass();
+        Method method = clazz.getMethod("fib", int.class);
+        Object result = method.invoke(object, 10);
+        Assertions.assertThat(result).isEqualTo(55L);
+    }
+}