Gp-138 bean post processor new exercise MAIN

3-0-spring-framework/bean-post-processor/README.MD

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+# <img src="https://raw.githubusercontent.com/bobocode-projects/resources/master/image/logo_transparent_background.png" height=50/>Bean Post Processor exercise
+Improve your *Spring* advanced skills 💪
+### Task
+Implement automatic String trimming functionality. So if I pass  "    Hello  "  as an argument to my bean’s method, or return it from the bean’s method, it gets automatically trimmed to "Hello".
+
+- create annotation @Trimmed that you can put on class
+
+- create annotation @EnableStringTrimming that will enable automatic String trimming for all beans that are annotated with @Trimmed
+
+- create TrimmedAnnotationBeanPostProcessor that will check for beans that are marked with @Trimmed,
+
+- create a proxy of those classes, and override methods. Proxy methods should:
+
+  - trim all String arguments
+
+  - trim all String return values
+
+- extract  TrimmedAnnotationBeanPostProcessor  into a separate StringTrimmingConfiguration that is imported by @EnableStringTrimming
+
+To verify your configuration, run `BeanPostProcessorTest.java`
+
+
+### Pre-conditions ❗
+You're supposed to be familiar with *Spring*
+
+### How to start ❓
+* Just clone the repository and start implementing the **todo** section, verify your changes by running tests
+* If you don't have enough knowledge about this domain, check out the [links below](#Related-materials-ℹ)
+* Don't worry if you got stuck, checkout the **exercise/completed** branch and see the final implementation
+
+### Related materials ℹ
+ todo
+
+---
+#### 🆕 First time here? – [See Introduction](https://github.com/bobocode-projects/java-fundamentals-course/tree/main/0-0-intro#introduction)
+
+##
+<div align="center"><img src="https://raw.githubusercontent.com/bobocode-projects/resources/master/animation/GitHub%20Star_3.gif" height=50/></div>

3-0-spring-framework/bean-post-processor/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>3-0-spring-framework</artifactId>
+        <groupId>com.bobocode</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>bean-post-processor</artifactId>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>cglib</groupId>
+            <artifactId>cglib</artifactId>
+            <version>3.3.0</version>
+        </dependency>
+    </dependencies>
+
+</project>

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/annotation/EnableStringTrimming.java

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+package com.bobocode.annotation;
+
+import com.bobocode.util.StringTrimmingConfiguration;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Configuration
+@Import(StringTrimmingConfiguration.class)
+public @interface EnableStringTrimming {
+}

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/annotation/Trimmed.java

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+package com.bobocode.annotation;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+@Retention(RetentionPolicy.RUNTIME)
+public @interface Trimmed {
+}

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/config/ApplicationConfig.java

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+package com.bobocode.config;
+
+import com.bobocode.annotation.EnableStringTrimming;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Configure the application for using @Trimmed annotation and corresponding logic.
+ */
+
+@Configuration
+@ComponentScan(basePackages = "com.bobocode.service")
+@EnableStringTrimming
+public class ApplicationConfig {
+
+}

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/service/TextService.java

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+package com.bobocode.service;
+
+import com.bobocode.annotation.Trimmed;
+import org.springframework.stereotype.Service;
+
+/**
+ * Configure the service to provide trimming process.
+ */
+
+@Service
+@Trimmed
+public class TextService {
+    public String savedText;
+    private final static String AVAILABLE_TEXT = "    Who cares about tabbing?    ";
+
+    public void saveText(String text){
+        savedText = text;
+    }
+
+    public String getAvailableText(){
+        return AVAILABLE_TEXT;
+    }
+}

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/util/StringTrimmingConfiguration.java

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+package com.bobocode.util;
+
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+public class StringTrimmingConfiguration {
+
+    @Bean
+    public BeanPostProcessor trimmedAnnotationBeanPostProcessor(){
+        return new TrimmedAnnotationBeanPostProcessor();
+    }
+}

3-0-spring-framework/bean-post-processor/src/main/java/com/bobocode/util/TrimmedAnnotationBeanPostProcessor.java

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+package com.bobocode.util;
+
+import com.bobocode.annotation.Trimmed;
+import net.sf.cglib.proxy.Enhancer;
+import net.sf.cglib.proxy.MethodInterceptor;
+import net.sf.cglib.proxy.MethodProxy;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+
+public class TrimmedAnnotationBeanPostProcessor implements BeanPostProcessor {
+    @Override
+    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+        Class<?> beanClass = bean.getClass();
+        if (beanClass.isAnnotationPresent(Trimmed.class)) {
+            return createTrimmedProxy(beanClass);
+        }
+        return bean;
+    }
+
+    private Object createTrimmedProxy(Class<?> beanClass) {
+        var enhancer = new Enhancer();
+        enhancer.setSuperclass(beanClass);
+        enhancer.setInterfaces(beanClass.getInterfaces());
+        MethodInterceptor interceptor = (Object obj, Method method, Object[] args, MethodProxy proxy) -> {
+            Object[] arguments = Arrays.stream(args)
+                    .filter(arg -> arg instanceof String)
+                    .map(arg -> ((String) arg).trim())
+                    .toArray();
+
+            if (method.getReturnType().equals(String.class)) {
+                String invokeSuper = (String) proxy.invokeSuper(obj, arguments);
+                return (String) invokeSuper.trim();
+            }
+            return proxy.invokeSuper(obj, arguments);
+        };
+        enhancer.setCallback(interceptor);
+        return beanClass.cast(enhancer.create());
+    }
+}