Phased builders via interfaces

gistfile1.txt

interface EmptyBuilder {
  BuilderWithId withId(String id)
}

gistfile2.txt

interface BuilderWithId {
  BuilderWithTotal withTotal(BigDecimal total)
}

gistfile3.txt

interface BuilderWithTotal {
  CompleteBuilder withPurchaseOrderNumber(String poNumber)
}

gistfile4.txt

interfce CompleteBuilder {
  Invoice build()
}

Invoice.java

public class Invoice {
  private String id;
  private BigDecimal total;
  private String poNumber;
  
  public static EmptyBuilder builder() {
    return new Invoice.Builder();
  }
  
  private static class Builder implements EmptyBuilder, BuilderwithId, BuilderWithTotal, CompleteBuilder {
    public BuilderWithId withId(String id) {
      return this;
    }
    
    public BuilderWithTotal withTotal(BigDecimal total) {
      return this;
    }
    
    public CompleteBuilder withPurchaseOrderNumber(String poNumber) {
      return this;
    }
    
    public Invoice build() {
      
    }
  }
}