39 lines
1.7 KiB
Markdown
39 lines
1.7 KiB
Markdown
---
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layout: pattern
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title: Builder
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folder: builder
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permalink: /patterns/builder/
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pumlid: DSR94O0m2030LhG0mzzkC64KXs26GzlNZw_TcRLADagJwOWOlW8OFcNdE79B9wkN1ccKUdLWoGS33KwySMdalEioC89C7Jhw5zYIfNrIrFybhPUHNLu0
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categories: Creational
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tags:
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- Java
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- Gang Of Four
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- Difficulty-Intermediate
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---
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## Intent
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Separate the construction of a complex object from its
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representation so that the same construction process can create different
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representations.
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## Applicability
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Use the Builder pattern when
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* the algorithm for creating a complex object should be independent of the parts that make up the object and how they're assembled
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* the construction process must allow different representations for the object that's constructed
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## Real world examples
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* [java.lang.StringBuilder](http://docs.oracle.com/javase/8/docs/api/java/lang/StringBuilder.html)
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* [java.nio.ByteBuffer](http://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html#put-byte-) as well as similar buffers such as FloatBuffer, IntBuffer and so on.
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* [java.lang.StringBuffer](http://docs.oracle.com/javase/8/docs/api/java/lang/StringBuffer.html#append-boolean-)
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* All implementations of [java.lang.Appendable](http://docs.oracle.com/javase/8/docs/api/java/lang/Appendable.html)
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* [Apache Camel builders](https://github.com/apache/camel/tree/0e195428ee04531be27a0b659005e3aa8d159d23/camel-core/src/main/java/org/apache/camel/builder)
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## Credits
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* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
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* [Effective Java (2nd Edition)](http://www.amazon.com/Effective-Java-Edition-Joshua-Bloch/dp/0321356683)
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