java-design-patterns/strangler/README.md

---
layout: pattern
title: Strangler
folder: strangler
permalink: /patterns/strangler/
categories: Structural
tags:
 - Extensibility
 - Cloud distributed
---

## Intent
Incrementally migrate a legacy system by gradually replacing specific pieces of functionality
with new applications and services. As features from the legacy system are replaced, the new
system eventually covers all the old system's features and may has its own new features, then
strangling the old system and allowing you to decommission it.

## Class diagram
![alt text](./etc/strangler.png "Strangler")

## Applicability
This strangler pattern is a safe way to phase one thing out for something better, cheaper, or 
more expandable. Especially when you want to update legacy system with new techniques and need 
continuously develop new features at the same time. Note that this pattern indeed need extra effort, 
so usually use it when the system is not so simple.

## Credits

* [Strangler pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/strangler)
* [Legacy Application Strangulation : Case Studies](https://paulhammant.com/2013/07/14/legacy-application-strangulation-case-studies/)
Pr/1235 Review (#1250) * Add simple implementation for strangler pattern. * Add strangler pattern in pom.xml. * change package name * Revert "change package name" This reverts commit 430bd9073ea7bea6430586a0953c77f1798aacc8. * Code review for strangler Delete final of method parameters. Add final to private members. Change package name. * Revert "Code review for strangler" This reverts commit d5063567083e0348d678a938bd749e17343bcb8e. * Revert "Revert "Code review for strangler"" This reverts commit c8fd65fda782749c4f74f6de85da0f271d3c48a8. * Remove unnecessary files 2020-07-04 17:05:46 +08:00			`---`
			`layout: pattern`
			`title: Strangler`
			`folder: strangler`
			`permalink: /patterns/strangler/`
			`categories: Structural`
			`tags:`
			`- Extensibility`
Update links and tags 2020-07-26 11:30:42 +03:00			`- Cloud distributed`
Pr/1235 Review (#1250) * Add simple implementation for strangler pattern. * Add strangler pattern in pom.xml. * change package name * Revert "change package name" This reverts commit 430bd9073ea7bea6430586a0953c77f1798aacc8. * Code review for strangler Delete final of method parameters. Add final to private members. Change package name. * Revert "Code review for strangler" This reverts commit d5063567083e0348d678a938bd749e17343bcb8e. * Revert "Revert "Code review for strangler"" This reverts commit c8fd65fda782749c4f74f6de85da0f271d3c48a8. * Remove unnecessary files 2020-07-04 17:05:46 +08:00			`---`

			`## Intent`
			`Incrementally migrate a legacy system by gradually replacing specific pieces of functionality`
			`with new applications and services. As features from the legacy system are replaced, the new`
			`system eventually covers all the old system's features and may has its own new features, then`
			`strangling the old system and allowing you to decommission it.`

			`## Class diagram`
			`![alt text](./etc/strangler.png "Strangler")`

			`## Applicability`
			`This strangler pattern is a safe way to phase one thing out for something better, cheaper, or`
			`more expandable. Especially when you want to update legacy system with new techniques and need`
			`continuously develop new features at the same time. Note that this pattern indeed need extra effort,`
			`so usually use it when the system is not so simple.`

			`## Credits`

Update links and tags 2020-07-26 11:30:42 +03:00			`* [Strangler pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/strangler)`
Pr/1235 Review (#1250) * Add simple implementation for strangler pattern. * Add strangler pattern in pom.xml. * change package name * Revert "change package name" This reverts commit 430bd9073ea7bea6430586a0953c77f1798aacc8. * Code review for strangler Delete final of method parameters. Add final to private members. Change package name. * Revert "Code review for strangler" This reverts commit d5063567083e0348d678a938bd749e17343bcb8e. * Revert "Revert "Code review for strangler"" This reverts commit c8fd65fda782749c4f74f6de85da0f271d3c48a8. * Remove unnecessary files 2020-07-04 17:05:46 +08:00			`* [Legacy Application Strangulation : Case Studies](https://paulhammant.com/2013/07/14/legacy-application-strangulation-case-studies/)`