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{{WikiProject
{{WikiProject Java|auto=inherit|importance=low}} {{WikiProject Computer science
}}
==Why builders?==
Builders are an OOP pattern to construct complex objects without overloading a constructor. The important part is that you don’t need to call all of the steps to construct. You can call only those steps that are necessary for producing a particular configuration of an object. Also a `director` class helps the builder to construct a specific type of object. I'm missing these concepts in the article. [[User:Theking2|Theking2]] ([[User talk:Theking2|talk]]) 20:52, 25 November 2024 (UTC)
:This is helpful. I've read the wiki and it's still isn't entirely clear to me how or why I would use this. [[User:Jgoure|Jgoure]] ([[User talk:Jgoure|talk]]) 21:49, 7 April 2025 (UTC)
==Builders and immutable objects==
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A major benefit of builders is that they can be used to create immutable objects without complex constructors. In Java, the builder pattern also simulates named constructor parameters:
<
public final class Pizza {
private final String dough;
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}
}
</syntaxhighlight>
==Abstract Builder class==
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This seems to say that the Builder manages "the correct sequence of object creation". Is the client the "Director" or is the builder the "Director"? <small>—The preceding [[Wikipedia:Sign your posts on talk pages|unsigned]] comment was added by [[Special:Contributions/61.14.96.7|61.14.96.7]] ([[User talk:61.14.96.7|talk]]) 07:51, 30 April 2007 (UTC).</small><!-- HagermanBot Auto-Unsigned -->
:According to the UML, the client is the Director. And I believe the word "Director" should be replaced with "Client" for clarity and to avoid confusion since some people tend to think "Director" is a class which is part of the pattern. [[Special:Contributions/186.0.181.64|186.0.181.64]] ([[User talk:186.0.181.64|talk]]) 17:46, 10 April 2023 (UTC)
== Missing the Mark ==
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== Two example implementations ==
I'm not sure we need two example implementations. C++ and Java are not radically different in syntax, and there's nothing about the pattern that can't be covered in one. — [[User:Anndelion|<
:Not terribly impressed by the C++ example either - don't expose pointers, use references instead, and the Builder certainly cannot be a singleton. As an example, use more meaningful names - ideally (necessarily) the same as those in other examples to emphasis the relationship between the representations in different languages. [[Special:Contributions/15.203.137.74|15.203.137.74]] ([[User talk:15.203.137.74|talk]]) 12:19, 26 November 2014 (UTC)
== C# implementation ==
In keeping with C# style, shouldn't properties be used instead of java-like setters?
<
public string Dough {
get {return _dough;}
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}
...
</syntaxhighlight>
== Critics ==
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<ref>http://stackoverflow.com/questions/26256604/is-the-java-builder-pattern-bloch-really-related-to-the-gof-builder</ref>
[[User:Normana400|Normana400]] ([[User talk:Normana400|talk]]) 18:47, 17 March 2017 (UTC)
{{reflist-talk}}
== Wrong example ==
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disappears:
<
class Pizza:
def __init__(self,dough='Hand Tossed', sauce='Marinara', topping='Cheese'):
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# Use the standard dough
p = Pizza(sauce='Garlic Butter', topping='Pepperoni')
</syntaxhighlight>
...But then, the "Definition" section of the article says this:
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A less abstract example might be DocumentBuilder with addParagraph, addImage etc methods. Then we could have a PdfDocumentBuilder, WordDocumentBuilder etc implementations. [[Special:Contributions/81.187.215.34|81.187.215.34]] ([[User talk:81.187.215.34|talk]]) 11:23, 10 July 2016 (UTC)
:The current example is no longer about cars. [[User:Dandv|<span style="text-shadow:lightgrey 0.3em 0.3em 0.15em;">Dandv</span>]] 04:33, 6 October 2022 (UTC)
== UML class and sequence diagram ==
I would like to share the following [[Unified Modeling Language|UML]] diagrams I have published on [http://www.w3sdesign.com Design Patterns Open Online Learning]. Your comments are welcomed!
[[File:w3sDesign Builder Design Pattern UML.jpg|frame|none|A sample UML class and sequence diagram for the Builder design pattern.]]
In the above [[Unified Modeling Language|UML]] [[Class diagram|class diagram]],
the <code>Director</code> class doesn't instantiate the <code>ProductA1</code> and <code>ProductB1</code> classes directly.
Instead, the <code>Director</code> refers to the <code>Builder</code> interface to create the objects,
which makes the <code>Director</code> independent of which concrete classes are instantiated (which representation of the complex object is created).
The <code>Builder1</code> class implements the <code>Builder</code> interface by creating and assembling the <code>ProductA1</code> and <code>ProductB1</code> objects
<br>
The [[Unified Modeling Language|UML]] [[Sequence diagram|sequence diagram]] shows the run-time interactions:
The <code>Director</code> object calls <code>buildPartA()</code> on the <code>Builder1</code> object, which creates and assembles the <code>ProductA1</code> object.
Thereafter,
the <code>Director</code> calls <code>BuildPartB()</code> on <code>Builder1</code>, which creates and assembles the <code>ProductB1</code> object. <br>
[[User:Vanderjoe|Vanderjoe]] ([[User talk:Vanderjoe|talk]]) 15:42, 5 August 2017 (UTC)<br>
== The many code examples seem unneeded. ==
If the point of the article is to convey the idea behind the pattern, I think the many, many different language implementations are unnecessary. By display length, the Examples section, with implementations in 9 (!) different languages takes up 80% of the article. This seems quite superfluous, since, unlike, say, an article on a sorting algorithm, nobody is going to copy and paste any of this code into their program.
I'd prefer to either completely remove the Examples section, or only keep, at most, a single language (don't care which).
[[User:Mlouns|Mlouns]] ([[User talk:Mlouns|talk]]) 22:43, 3 June 2019 (UTC)
:This was resolved. Can we delete the section? [[User:Dandv|<span style="text-shadow:lightgrey 0.3em 0.3em 0.15em;">Dandv</span>]] 04:32, 6 October 2022 (UTC)
== Confusing Bicycle example ==
I find the Pizza example given on this Talk page in 2007 ([[#Builders_and_immutable_objects]]) far easier to follow than the [https://en.wikipedia.org/w/index.php?title=Builder_pattern&oldid=1102311912#Examples current Bicycle example]. -- [[User:Dandv|<span style="text-shadow:lightgrey 0.3em 0.3em 0.15em;">Dandv</span>]] 04:30, 6 October 2022 (UTC)
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