Javapoet: Add code to a method

Using ‘addCode’ method of MethodBuilder, you can add the code to a method.

 

Example

methodBuilder.addCode("int i = 0;\n"
        + "int j = 0;\n"
        + "\n"
        + "for(int i = 0; i < 10; i++){\n"
        + "    for(int j = 0; j < i; j++){\n"
        + "        System.out.print(\"*\");\n"
        + "    }\n"
        + "    System.out.println();\n"
        + "}");

 

Find the below working application.

 

AddMethodToAMethod.java

package com.sample.app;

import java.io.IOException;

import javax.lang.model.element.Modifier;

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

public class AddMethodToAMethod {

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

        MethodSpec.Builder methodBuilder = MethodSpec.methodBuilder("main");
        methodBuilder.addModifiers(Modifier.PUBLIC, Modifier.STATIC);
        methodBuilder.returns(void.class);
        methodBuilder.addParameter(String[].class, "args");

        methodBuilder.addComment("Print stars triangle");
        methodBuilder.addCode("int i = 0;\n"
                + "int j = 0;\n"
                + "\n"
                + "for(int i = 0; i < 10; i++){\n"
                + "    for(int j = 0; j < i; j++){\n"
                + "        System.out.print(\"*\");\n"
                + "    }\n"
                + "    System.out.println();\n"
                + "}");
        
        MethodSpec mainMethodSpec = methodBuilder.build();
        
        
        String className = "HelloWorld";
        TypeSpec.Builder classBuilder = TypeSpec.classBuilder(className);
        classBuilder.addModifiers(Modifier.PUBLIC, Modifier.FINAL);
        classBuilder.addMethod(mainMethodSpec);
        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;

public final class HelloWorld {
  public static void main(String[] args) {
    // Print stars triangle
    int i = 0;
    int j = 0;

    for(int i = 0; i < 10; i++){
        for(int j = 0; j < i; j++){
            System.out.print("*");
        }
        System.out.println();
    }
  }
}

 

 

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