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Added samples for annotation processing article. (#705) 

* Added annotation processing examples. Fixed core-java8 build on OS X

* Moved projects to separate submodule
This commit is contained in:
Sergey Petunin 2016-09-28 19:24:03 +05:00 committed by Grzegorz Piwowarek
parent d1bd04d2dc
commit ea85fa99ee
11 changed files with 319 additions and 14 deletions
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50
annotations/annotation-processing/pom.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://maven.apache.org/POM/4.0.0"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
<artifactId>annotations</artifactId>
<relativePath>../</relativePath>
</parent>
<artifactId>annotation-processing</artifactId>
<properties>
<auto-service.version>1.0-rc2</auto-service.version>
<maven-compiler-plugin.version>3.5.1</maven-compiler-plugin.version>
</properties>
<dependencies>
<dependency>
<groupId>com.google.auto.service</groupId>
<artifactId>auto-service</artifactId>
<version>${auto-service.version}</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

132
annotations/annotation-processing/src/main/java/com/baeldung/annotation/processor/BuilderProcessor.java Normal file
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package com.baeldung.annotation.processor;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;
import javax.annotation.processing.*;
import javax.lang.model.SourceVersion;
import javax.lang.model.element.Element;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.ExecutableType;
import javax.tools.Diagnostic;
import javax.tools.JavaFileObject;
import com.google.auto.service.AutoService;
@SupportedAnnotationTypes("com.baeldung.annotation.processor.BuilderProperty")
@SupportedSourceVersion(SourceVersion.RELEASE_8)
@AutoService(Processor.class)
public class BuilderProcessor extends AbstractProcessor {
@Override
public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
for (TypeElement annotation : annotations) {
Set<? extends Element> annotatedElements = roundEnv.getElementsAnnotatedWith(annotation);
Map<Boolean, List<Element>> annotatedMethods = annotatedElements.stream()
.collect(Collectors.partitioningBy(element ->
((ExecutableType) element.asType()).getParameterTypes().size() == 1
&& element.getSimpleName().toString().startsWith("set")));
List<Element> setters = annotatedMethods.get(true);
List<Element> otherMethods = annotatedMethods.get(false);
otherMethods.forEach(element ->
processingEnv.getMessager().printMessage(Diagnostic.Kind.ERROR,
"@BuilderProperty must be applied to a setXxx method with a single argument", element));
if (setters.isEmpty()) {
continue;
}
String className = ((TypeElement) setters.get(0).getEnclosingElement()).getQualifiedName().toString();
Map<String, String> setterMap = setters.stream().collect(Collectors.toMap(
setter -> setter.getSimpleName().toString(),
setter -> ((ExecutableType) setter.asType())
.getParameterTypes().get(0).toString()
));
try {
writeBuilderFile(className, setterMap);
} catch (IOException e) {
e.printStackTrace();
}
}
return true;
}
private void writeBuilderFile(String className, Map<String, String> setterMap) throws IOException {
String packageName = null;
int lastDot = className.lastIndexOf('.');
if (lastDot > 0) {
packageName = className.substring(0, lastDot);
}
String simpleClassName = className.substring(lastDot + 1);
String builderClassName = className + "Builder";
String builderSimpleClassName = builderClassName.substring(lastDot + 1);
JavaFileObject builderFile = processingEnv.getFiler().createSourceFile(builderClassName);
try (PrintWriter out = new PrintWriter(builderFile.openWriter())) {
if (packageName != null) {
out.print("package ");
out.print(packageName);
out.println(";");
out.println();
}
out.print("public class ");
out.print(builderSimpleClassName);
out.println(" {");
out.println();
out.print(" private ");
out.print(simpleClassName);
out.print(" object = new ");
out.print(simpleClassName);
out.println("();");
out.println();
out.print(" public ");
out.print(simpleClassName);
out.println(" build() {");
out.println(" return object;");
out.println(" }");
out.println();
setterMap.entrySet().forEach(setter -> {
String methodName = setter.getKey();
String argumentType = setter.getValue();
out.print(" public ");
out.print(builderSimpleClassName);
out.print(" ");
out.print(methodName);
out.print("(");
out.print(argumentType);
out.println(" value) {");
out.print(" object.");
out.print(methodName);
out.println("(value);");
out.println(" return this;");
out.println(" }");
out.println();
});
out.println("}");
}
}
}

8
annotations/annotation-processing/src/main/java/com/baeldung/annotation/processor/BuilderProperty.java Normal file
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package com.baeldung.annotation.processor;
import java.lang.annotation.*;
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.SOURCE)
public @interface BuilderProperty {
}

51
annotations/annotation-user/pom.xml Normal file
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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">
<modelVersion>4.0.0</modelVersion>
<parent>
<artifactId>annotations</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
<relativePath>../</relativePath>
</parent>
<artifactId>annotation-user</artifactId>
<dependencies>
<dependency>
<groupId>com.baeldung</groupId>
<artifactId>annotation-processing</artifactId>
<version>${project.parent.version}</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
</project>

29
annotations/annotation-user/src/main/java/com/baeldung/annotation/Person.java Normal file
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package com.baeldung.annotation;
import com.baeldung.annotation.processor.BuilderProperty;
public class Person {
private int age;
private String name;
public int getAge() {
return age;
}
@BuilderProperty
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
@BuilderProperty
public void setName(String name) {
this.name = name;
}
}

22
annotations/annotation-user/src/test/java/com/baeldung/annotation/PersonBuilderTest.java Normal file
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package com.baeldung.annotation;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class PersonBuilderTest {
@Test
public void whenBuildPersonWithBuilder_thenObjectHasPropertyValues() {
Person person = new PersonBuilder()
.setAge(25)
.setName("John")
.build();
assertEquals(25, person.getAge());
assertEquals("John", person.getName());
}
}

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annotations/pom.xml Normal file
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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>parent-modules</artifactId>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>annotations</artifactId>
<packaging>pom</packaging>
<modules>
<module>annotation-processing</module>
<module>annotation-user</module>
</modules>
</project>

6
core-java-8/pom.xml
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@ -1,9 +1,10 @@
<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">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baeldung</groupId>
<version>1.0.0-SNAPSHOT</version>
<artifactId>core-java8</artifactId>
<version>0.1-SNAPSHOT</version>
<name>core-java8</name>
@ -111,6 +112,9 @@
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!-- logging -->
<org.slf4j.version>1.7.13</org.slf4j.version>
<logback.version>1.0.13</logback.version>

13
core-java-8/src/test/resources/.gitignore vendored
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@ -1,13 +0,0 @@
*.class
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
# Packaged files #
*.jar
*.war
*.ear

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core-java-8/src/test/resources/test.txt Normal file
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Lorem ipsum dolor sit amet, consectetur adipiscing elit. Suspendisse facilisis neque sed turpis venenatis, non dignissim risus volutpat.

1
pom.xml
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@ -132,6 +132,7 @@
<module>wicket</module>
<module>xstream</module>
<module>java-cassandra</module>
<module>annotations</module>
</modules>
</project>