Create AOP examples

- Use different types of advice
- Use various types of pointcut expressions

spring-mvc-java/src/main/java/org/baeldung/aop/LoggingAspect.java

@@ -0,0 +1,34 @@
+package org.baeldung.aop;
+
+import org.aspectj.lang.JoinPoint;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Before;
+import org.aspectj.lang.annotation.Pointcut;
+import org.springframework.stereotype.Component;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.logging.Logger;
+
+@Component
+@Aspect
+public class LoggingAspect {
+
+    private static Logger logger = Logger.getLogger(LoggingAspect.class.getName());
+
+    private ThreadLocal<SimpleDateFormat> sdf = new ThreadLocal<SimpleDateFormat>() {
+        @Override
+        protected SimpleDateFormat initialValue() {
+            return new SimpleDateFormat("[yyyy-mm-dd hh:mm:ss:SSS]");
+        }
+    };
+
+    @Pointcut("@target(org.springframework.stereotype.Repository)")
+    public void repositoryMethods() {}
+
+    @Before("repositoryMethods()")
+    public void logMethodCall(JoinPoint jp) throws Throwable {
+        String methodName = jp.getSignature().getName();
+        logger.info(sdf.get().format(new Date()) + methodName);
+    }
+}

spring-mvc-java/src/main/java/org/baeldung/aop/PerformanceAspect.java

@@ -16,7 +16,7 @@ public class PerformanceAspect {
     private static Logger logger = Logger.getLogger(PerformanceAspect.class.getName());
 
     @Pointcut("within(@org.springframework.stereotype.Repository *)")
-    public void repositoryClassMethods() {};
+    public void repositoryClassMethods() {}
 
     @Around("repositoryClassMethods()")
     public Object measureMethodExecutionTime(ProceedingJoinPoint pjp) throws Throwable {

spring-mvc-java/src/main/java/org/baeldung/aop/PublishingAspect.java

@@ -0,0 +1,36 @@
+package org.baeldung.aop;
+
+import org.aspectj.lang.JoinPoint;
+import org.aspectj.lang.annotation.AfterReturning;
+import org.aspectj.lang.annotation.Aspect;
+import org.aspectj.lang.annotation.Pointcut;
+import org.baeldung.events.FooCreationEvent;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.ApplicationEventPublisher;
+import org.springframework.stereotype.Component;
+
+@Component
+@Aspect
+public class PublishingAspect {
+
+    private ApplicationEventPublisher eventPublisher;
+
+    @Autowired
+    public void setEventPublisher(ApplicationEventPublisher eventPublisher) {
+        this.eventPublisher = eventPublisher;
+    }
+
+    @Pointcut("@target(org.springframework.stereotype.Repository)")
+    public void repositoryMethods() {}
+
+    @Pointcut("execution(* *..create*(Long,..))")
+    public void firstLongParamMethods() {}
+
+    @Pointcut("repositoryMethods() && firstLongParamMethods()")
+    public void entityCreationMethods() {}
+
+    @AfterReturning(value = "entityCreationMethods()", returning = "entity")
+    public void logMethodCall(JoinPoint jp, Object entity) throws Throwable {
+        eventPublisher.publishEvent(new FooCreationEvent(entity));
+    }
+}

spring-mvc-java/src/main/java/org/baeldung/dao/FooDao.java

@@ -1,10 +1,16 @@
 package org.baeldung.dao;
 
+import org.baeldung.model.Foo;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public class FooDao {
+
     public String findById(Long id) {
         return "Bazz";
     }
+
+    public Foo create(Long id, String name) {
+        return new Foo(id, name);
+    }
 }

spring-mvc-java/src/main/java/org/baeldung/events/FooCreationEvent.java

@@ -0,0 +1,10 @@
+package org.baeldung.events;
+
+import org.springframework.context.ApplicationEvent;
+
+public class FooCreationEvent extends ApplicationEvent {
+
+    public FooCreationEvent(Object source) {
+        super(source);
+    }
+}

spring-mvc-java/src/main/java/org/baeldung/events/FooCreationEventListener.java

@@ -0,0 +1,17 @@
+package org.baeldung.events;
+
+import org.springframework.context.ApplicationListener;
+import org.springframework.stereotype.Component;
+
+import java.util.logging.Logger;
+
+@Component
+public class FooCreationEventListener implements ApplicationListener<FooCreationEvent> {
+
+    private static Logger logger = Logger.getLogger(FooCreationEventListener.class.getName());
+
+    @Override
+    public void onApplicationEvent(FooCreationEvent event) {
+        logger.info("Created foo instance: " + event.getSource().toString());
+    }
+}

spring-mvc-java/src/main/java/org/baeldung/model/Foo.java

@@ -0,0 +1,19 @@
+package org.baeldung.model;
+
+public class Foo {
+    private Long id;
+    private String name;
+
+    public Foo(Long id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    @Override
+    public String toString() {
+        return "Foo{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                '}';
+    }
+}

spring-mvc-java/src/main/resources/org/baeldung/aop/beans.xml

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns:aop="http://www.springframework.org/schema/aop"
+       xsi:schemaLocation="http://www.springframework.org/schema/beans
+        http://www.springframework.org/schema/beans/spring-beans-4.2.xsd
+        http://www.springframework.org/schema/aop
+        http://www.springframework.org/schema/aop/spring-aop-4.2.xsd">
+
+    <bean id="perfomanceMeter" class="org.baeldung.aop.PerformanceAspect"/>
+    <bean id="fooDao" class="org.baeldung.dao.FooDao"/>
+
+    <aop:config>
+        <aop:pointcut id="anyDaoMethod" expression="@target(org.springframework.stereotype.Repository)"/>
+        <aop:aspect ref="perfomanceMeter">
+            <aop:around method="measureMethodExecutionTime" pointcut-ref="anyDaoMethod"/>
+        </aop:aspect>
+    </aop:config>
+</beans>

spring-mvc-java/src/test/java/org/baeldung/aop/AopLoggingTest.java

@@ -0,0 +1,67 @@
+package org.baeldung.aop;
+
+import org.baeldung.config.TestConfig;
+import org.baeldung.dao.FooDao;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Handler;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+import static org.hamcrest.Matchers.hasSize;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = {TestConfig.class}, loader = AnnotationConfigContextLoader.class)
+public class AopLoggingTest {
+
+    @Before
+    public void setUp() {
+        logEventHandler = new Handler() {
+            @Override
+            public void publish(LogRecord record) {
+                messages.add(record.getMessage());
+            }
+
+            @Override
+            public void flush() {
+            }
+
+            @Override
+            public void close() throws SecurityException {
+            }
+        };
+
+        messages = new ArrayList<>();
+    }
+
+    @Autowired
+    private FooDao dao;
+
+    private Handler logEventHandler;
+
+    private List<String> messages;
+
+    @Test
+    public void givenLoggingAspect_whenCallDaoMethod_thenBeforeAdviceIsCalled() {
+        Logger logger = Logger.getLogger(LoggingAspect.class.getName());
+        logger.addHandler(logEventHandler);
+
+        dao.findById(1L);
+        assertThat(messages, hasSize(1));
+
+        String logMessage = messages.get(0);
+        Pattern pattern = Pattern.compile("^\\[\\d{4}\\-\\d{2}\\-\\d{2} \\d{2}:\\d{2}:\\d{2}:\\d{3}\\]findById$");
+        assertTrue(pattern.matcher(logMessage).matches());
+    }
+}

spring-mvc-java/src/test/java/org/baeldung/aop/AopPublishingTest.java

@@ -0,0 +1,67 @@
+package org.baeldung.aop;
+
+import org.baeldung.config.TestConfig;
+import org.baeldung.dao.FooDao;
+import org.baeldung.events.FooCreationEventListener;
+import org.baeldung.model.Foo;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.test.context.support.AnnotationConfigContextLoader;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Handler;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+import static org.junit.Assert.assertTrue;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = {TestConfig.class}, loader = AnnotationConfigContextLoader.class)
+public class AopPublishingTest {
+
+    @Before
+    public void setUp() {
+        logEventHandler = new Handler() {
+            @Override
+            public void publish(LogRecord record) {
+                messages.add(record.getMessage());
+            }
+
+            @Override
+            public void flush() {
+            }
+
+            @Override
+            public void close() throws SecurityException {
+            }
+        };
+
+        messages = new ArrayList<>();
+    }
+
+    @Autowired
+    private FooDao dao;
+
+    private Handler logEventHandler;
+
+    private List<String> messages;
+
+    @Test
+    public void givenPublishingAspect_whenCallCreate_thenCreationEventIsPublished() {
+        Logger logger = Logger.getLogger(FooCreationEventListener.class.getName());
+        logger.addHandler(logEventHandler);
+
+        dao.create(1L, "Bar");
+
+        String logMessage = messages.get(0);
+        Pattern pattern = Pattern.compile("Created foo instance: " +
+                Pattern.quote(new Foo(1L, "Bar").toString()));
+        assertTrue(pattern.matcher(logMessage).matches());
+    }
+}

spring-mvc-java/src/test/java/org/baeldung/aop/AopXmlConfigPerformanceTest.java

@@ -0,0 +1,67 @@
+package org.baeldung.aop;
+
+import org.baeldung.dao.FooDao;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Handler;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+import static org.hamcrest.CoreMatchers.notNullValue;
+import static org.hamcrest.Matchers.hasSize;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration("/org/baeldung/aop/beans.xml")
+public class AopXmlConfigPerformanceTest {
+
+    @Before
+    public void setUp() {
+        logEventHandler = new Handler() {
+            @Override
+            public void publish(LogRecord record) {
+                messages.add(record.getMessage());
+            }
+
+            @Override
+            public void flush() {
+            }
+
+            @Override
+            public void close() throws SecurityException {
+            }
+        };
+
+        messages = new ArrayList<>();
+    }
+
+    @Autowired
+    private FooDao dao;
+
+    private Handler logEventHandler;
+
+    private List<String> messages;
+
+    @Test
+    public void givenPerformanceAspect_whenCallDaoMethod_thenPerformanceMeasurementAdviceIsCalled() {
+        Logger logger = Logger.getLogger(PerformanceAspect.class.getName());
+        logger.addHandler(logEventHandler);
+
+        final String entity = dao.findById(1L);
+        assertThat(entity, notNullValue());
+        assertThat(messages, hasSize(1));
+
+        String logMessage = messages.get(0);
+        Pattern pattern = Pattern.compile("Execution of findById took \\d+ ms");
+        assertTrue(pattern.matcher(logMessage).matches());
+    }
+}

spring-mvc-java/src/test/java/org/baeldung/config/TestConfig.java

@@ -5,7 +5,7 @@
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
 
 @Configuration
-@ComponentScan(basePackages = {"org.baeldung.dao", "org.baeldung.aop"})
+@ComponentScan(basePackages = {"org.baeldung.dao", "org.baeldung.aop", "org.baeldung.events"})
 @EnableAspectJAutoProxy
 public class TestConfig {
 }