Javapoet: Generate if-else if ladder

‘nextControlFlow()’ method is used to generate connected control flow statements.

methodBuilder.beginControlFlow("if(marks < 35)")
      .addStatement("System.out.println(\"You are failed\")")
      .nextControlFlow("else if( marks < 50)")
      .addStatement("System.out.println(\"You are passed and got third class\")")
      .nextControlFlow("else if( marks < 60)")
      .addStatement("System.out.println(\"You are passed and got second class\")")
      .nextControlFlow("else if( marks < 70)")
      .addStatement("System.out.println(\"You are passed and got first class\")")
      .nextControlFlow("else")
      .addStatement("System.out.println(\"You are passed and got distinction\")")
      .endControlFlow()
      .build();

 

Above snippet generates following java code.

  if(marks < 35) {
    System.out.println("You are failed");
  } else if( marks < 50) {
    System.out.println("You are passed and got third class");
  } else if( marks < 60) {
    System.out.println("You are passed and got second class");
  } else if( marks < 70) {
    System.out.println("You are passed and got first class");
  } else {
    System.out.println("You are passed and got distinction");
  }

 

Find the below working application.

 

IfElseIfLadderDemo.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 IfElseIfLadderDemo {

      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.addCode("\n");
            methodBuilder.addStatement("int marks = 45");
            
            methodBuilder.beginControlFlow("if(marks < 35)")
                              .addStatement("System.out.println(\"You are failed\")")
                              .nextControlFlow("else if( marks < 50)")
                              .addStatement("System.out.println(\"You are passed and got third class\")")
                              .nextControlFlow("else if( marks < 60)")
                              .addStatement("System.out.println(\"You are passed and got second class\")")
                              .nextControlFlow("else if( marks < 70)")
                              .addStatement("System.out.println(\"You are passed and got first class\")")
                              .nextControlFlow("else")
                              .addStatement("System.out.println(\"You are passed and got distinction\")")
                              .endControlFlow()
                              .build();

            MethodSpec mainMethod = methodBuilder.build();

            String className = "Test";
            TypeSpec.Builder classBuilder = TypeSpec.classBuilder(className);
            classBuilder.addModifiers(Modifier.PUBLIC, Modifier.FINAL);
            classBuilder.addMethod(mainMethod);
            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 Test {
  public static void main(String[] args) {

    int marks = 45;
    if(marks < 35) {
      System.out.println("You are failed");
    } else if( marks < 50) {
      System.out.println("You are passed and got third class");
    } else if( marks < 60) {
      System.out.println("You are passed and got second class");
    } else if( marks < 70) {
      System.out.println("You are passed and got first class");
    } else {
      System.out.println("You are passed and got distinction");
    }
  }
}

 

 

 

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