Javapoet: Set properties on annotations

‘AnnotationSpec.builder’ is used to add properties to the annotaitons.

 

Example

MethodSpec toStringSpec = MethodSpec.methodBuilder("connectionString").addModifiers(Modifier.PUBLIC)
                .addStatement("return jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;")
                .returns(String.class).addAnnotation(AnnotationSpec.builder(Resource.class)
                        .addMember("name", "$S", "datasource").addMember("shareable", "false").build())
                .build();

 

Above snippet generates following code.

  @Resource(
      name = "datasource",
      shareable = false
  )
  public String connectionString() {
    return jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;;
  }

 

Find the below working application.

 

AnnotationDemo2.java

package com.sample.app;

import java.io.IOException;

import javax.annotation.Resource;
import javax.lang.model.element.Modifier;

import com.squareup.javapoet.AnnotationSpec;
import com.squareup.javapoet.JavaFile;
import com.squareup.javapoet.MethodSpec;
import com.squareup.javapoet.TypeSpec;

public class AnnotationDemo2 {

    public static void main(String args[]) throws IOException {

        MethodSpec toStringSpec = MethodSpec.methodBuilder("connectionString").addModifiers(Modifier.PUBLIC)
                .addStatement("return jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;")
                .returns(String.class).addAnnotation(AnnotationSpec.builder(Resource.class)
                        .addMember("name", "$S", "datasource").addMember("shareable", "false").build())
                .build();

        String className = "HelloWorld";
        TypeSpec.Builder classBuilder = TypeSpec.classBuilder(className);
        classBuilder.addModifiers(Modifier.PUBLIC, Modifier.FINAL);
        classBuilder.addMethod(toStringSpec);
        TypeSpec helloWorldTypeSpec = classBuilder.build();

        String packageName = "com.sample.app";
        JavaFile javaFile = JavaFile.builder(packageName, helloWorldTypeSpec).build();

        javaFile.writeTo(System.out);
    }

}

 

Generated code

package com.sample.app;

import java.lang.String;
import javax.annotation.Resource;

public final class HelloWorld {
  @Resource(
      name = "datasource",
      shareable = false
  )
  public String connectionString() {
    return jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;;
  }
}

 

 

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