BlindBuilder.java

// ==============================
// This gist contains the code from
// http://programmers.stackexchange.com/questions/228939/how-to-improve-upon-blochs-builder-pattern-to-make-it-more-appropriate-for-use
//
// Compare with the functional version at https://gist.github.com/swlaschin/9008814
// ==============================


// ==========================================
// UserConfig.java
// ==========================================


import  java.util.regex.Pattern;
/**
   <P>Information about a user -- <I>[builder: UserConfig_Cfg]</I></P>
   <P>Validation of all fields occurs in this classes constructor. However, each validation requirement is document only in the builder's setter functions.</P>
   <P>{@code java xbn.z.xmpl.lang.builder.finalv.UserConfig}</P>
 **/
public class UserConfig  {
   public static final void main(String[] igno_red)  {
      UserConfig uc = new UserConfig_Cfg("Kermit").age(50).favoriteColor("green").build();
      System.out.println(uc);
   }
   private final String sName    ;
   private final int    iAge     ;
   private final String sFavColor;
   /**
      <P>Create a new instance. This sets and validates all fields.</P>
      @param  uc_f  May not be {@code null}.
    **/
   public UserConfig(UserConfig_Fieldable uc_f)  {
      //transfer
         try  {
            sName  = uc_f.getName();
         }  catch(NullPointerException rx)  {
            throw  new NullPointerException("uc_f");
         }
         iAge      = uc_f.getAge();
         sFavColor = uc_f.getFavoriteColor();
      //validate
         try  {
            if(!Pattern.compile("\\w+").matcher(sName).matches())  {
               throw  new IllegalArgumentException("uc_f.getName() (\"" + sName + "\") may not be empty, and must contain only letters digits and underscores.");
            }
         }  catch(NullPointerException rx)  {
            throw  new NullPointerException("uc_f.getName()");
         }
         if(iAge < 0)  {
            throw  new IllegalArgumentException("uc_f.getAge() (" + iAge + ") is less than zero.");
         }
         try  {
            if(!Pattern.compile("(?:red|blue|green|hot pink)").matcher(sFavColor).matches())  {
               throw  new IllegalArgumentException("uc_f.getFavoriteColor() (\"" + uc_f.getFavoriteColor() + "\") is not red, blue, green, or hot pink.");
            }
         }  catch(NullPointerException rx)  {
            throw  new NullPointerException("uc_f.getFavoriteColor()");
         }
   }
   //getters...START
      /**
         <P>The user's name.</P>
         @return  A non-{@code null}, non-empty string.
         @see  UserConfig_Cfg#UserConfig_Cfg(String)
         @see  #getAge()
         @see  #getFavoriteColor()
       **/
      public String getName()  {
         return  sName;
      }
      /**
         <P>The user's age.</P>
         @return  A number greater-than-or-equal-to zero.
         @see  UserConfig_Cfg#age(int)
         @see  #getName()
       **/
      public int getAge()  {
         return  iAge;
      }
      /**
         <P>The user's favorite color.</P>
         @return  A non-{@code null}, non-empty string.
         @see  UserConfig_Cfg#age(int)
         @see  #getName()
       **/
      public String getFavoriteColor()  {
         return  sFavColor;
      }
   //getters...END
   public String toString()  {
      return  "getName()=" + getName() + ", getAge()=" + getAge() + ", getFavoriteColor()=" + getFavoriteColor();
   }
}

// ==========================================
// UserConfig_Fieldable.java
// ==========================================

/**
   <P>Required by the {@link UserConfig} {@code UserConfig#UserConfig(UserConfig_Fieldable) constructor}.</P>
 **/
public interface UserConfig_Fieldable  {
   String getName();
   int getAge();
   String getFavoriteColor();
}


// ==========================================
// UserConfig_Cfg.java
// ==========================================


import  java.util.regex.Pattern;
/**
   <P>Builder for {@link UserConfig}.</P>
   <P>Validation of all fields occurs in the <CODE>UserConfig</CODE> constructor. However, each validation requirement is document only in this classes setter functions.</P>
 **/
public class UserConfig_Cfg implements UserConfig_Fieldable  {
   public String sName    ;
   public int    iAge     ;
   public String sFavColor;
   /**
      <P>Create a new instance with the user's name.</P>
      @param  s_name  May not be {@code null} or empty, and must contain only letters, digits, and underscores. Get with {@code UserConfig#getName() getName()}{@code ()}*.
    **/
   public UserConfig_Cfg(String s_name)  {
      sName = s_name;
   }
   //self-returning setters...START
      /**
         <P>Set the user's age.</P>
         @param  i_age  May not be less than zero. Get with {@code UserConfig#getName() getName()}{@code ()}*.
         @see  #favoriteColor(String)
       **/
      public UserConfig_Cfg age(int i_age)  {
         iAge = i_age;
         return  this;
      }
      /**
         <P>Set the user's favorite color.</P>
         @param  s_color  Must be {@code "red"}, {@code "blue"}, {@code green}, or {@code "hot pink"}. Get with {@code UserConfig#getName() getName()}{@code ()}*.
         @see  #age(int)
       **/
      public UserConfig_Cfg favoriteColor(String s_color)  {
         sFavColor = s_color;
         return  this;
      }
   //self-returning setters...END
   //getters...START
      public String getName()  {
         return  sName;
      }
      public int getAge()  {
         return  iAge;
      }
      public String getFavoriteColor()  {
         return  sFavColor;
      }
   //getters...END
   /**
      <P>Build the UserConfig, as configured.</P>
      @return  <CODE>(new {@link UserConfig#UserConfig(UserConfig_Fieldable) UserConfig}(this))</CODE>
    **/
   public UserConfig build()  {
      return  (new UserConfig(this));
   }
}