Javapoet: Add statements to the method

‘addStatement’ method of MethodSpec builder class is used to add statements to a method. ‘addStatement’ method handles adding semicolon at the end, line wrapping etc.,

 

Example

MethodSpec.Builder methodSpecBuilder = MethodSpec.methodBuilder("main");
methodSpecBuilder.addStatement("int i = 0, j = 0");

 

Find the below working application.

 

AddStatementToAMethod.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 AddStatementToAMethod {

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

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

        methodSpecBuilder.addCode("\n");
        methodSpecBuilder.addComment("Print stars triangle");
        methodSpecBuilder.addStatement("int i = 0, j = 0");
        methodSpecBuilder.beginControlFlow("while(i < 10)");
        methodSpecBuilder.beginControlFlow("while(j < 10)");
        methodSpecBuilder.addStatement("System.out.print(\"*\")");
        methodSpecBuilder.addStatement("j++");
        methodSpecBuilder.endControlFlow();
        methodSpecBuilder.addStatement("i++");
        methodSpecBuilder.addStatement("j = 0");
        methodSpecBuilder.addCode("\n");
        methodSpecBuilder.endControlFlow();

        MethodSpec mainMethodSpec = methodSpecBuilder.build();

        String className = "HelloWorld";
        TypeSpec.Builder classSpecBuilder = TypeSpec.classBuilder(className);
        classSpecBuilder.addModifiers(Modifier.PUBLIC, Modifier.FINAL);
        classSpecBuilder.addMethod(mainMethodSpec);
        TypeSpec helloWorldTypeSpec = classSpecBuilder.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, j = 0;
    while(i < 10) {
      while(j < 10) {
        System.out.print("*");
        j++;
      }
      i++;
      j = 0;

    }
  }
}

 

 

 

 

 

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