java-design-patterns/double-dispatch/README.md

---
layout: pattern
title: Double Dispatch
folder: double-dispatch
permalink: /patterns/double-dispatch/
pumlid: NSbB3iCW303HgpG70Ezx6yTOWSeOv4zp_MRTtUZDCPGa6wV9gqTiVmCOtlKQqVDCPwEbmHgLreGXUMEWmGU_M1hxkBHiZ61JXud-1BILft1fmvz37JZetshQh3kd_000
categories: Other
tags:
 - Java
 - Difficulty-Intermediate
 - Idiom
---

## Intent
Double Dispatch pattern is a way to create maintainable dynamic
behavior based on receiver and parameter types.

![alt text](./etc/double-dispatch.png "Double Dispatch")

## Applicability
Use the Double Dispatch pattern when

* the dynamic behavior is not defined only based on receiving object's type but also on the receiving method's parameter type.

## Real world examples

* [ObjectOutputStream](https://docs.oracle.com/javase/8/docs/api/java/io/ObjectOutputStream.html)
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00			`---`
			`layout: pattern`
			`title: Double Dispatch`
			`folder: double-dispatch`
Work towards #56: Add permalink to every pattern This makes cleaner URLs thanks to jekyll 2015-08-15 18:03:05 +02:00			`permalink: /patterns/double-dispatch/`
Work on #190: Commit initial pumlId's added by the script 2016-08-30 15:10:34 +02:00			`pumlid: NSbB3iCW303HgpG70Ezx6yTOWSeOv4zp_MRTtUZDCPGa6wV9gqTiVmCOtlKQqVDCPwEbmHgLreGXUMEWmGU_M1hxkBHiZ61JXud-1BILft1fmvz37JZetshQh3kd_000`
Work on #213 - properly categorize all patterns - remove pattern list from readme - minor fixes to readme - removed "introduction" because its not a pattern and an error i committed some time ago 2015-08-20 21:40:07 +02:00			`categories: Other`
Categorize and tag all patterns #213 2015-12-28 15:52:44 +02:00			`tags:`
			`- Java`
			`- Difficulty-Intermediate`
			`- Idiom`
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00			`---`

Use headings instead of bold text in index.md #238 2016-01-03 21:14:30 +01:00			`## Intent`
			`Double Dispatch pattern is a way to create maintainable dynamic`
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00			`behavior based on receiver and parameter types.`

			`![alt text](./etc/double-dispatch.png "Double Dispatch")`

Use headings instead of bold text in index.md #238 2016-01-03 21:14:30 +01:00			`## Applicability`
			`Use the Double Dispatch pattern when`
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00
			`* the dynamic behavior is not defined only based on receiving object's type but also on the receiving method's parameter type.`

Use headings instead of bold text in index.md #238 2016-01-03 21:14:30 +01:00			`## Real world examples`
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00
Work towards #56: Add permalink to every pattern This makes cleaner URLs thanks to jekyll 2015-08-15 18:03:05 +02:00			`* [ObjectOutputStream](https://docs.oracle.com/javase/8/docs/api/java/io/ObjectOutputStream.html)`