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walkmod an open source tool to apply coding conventions

Raquel Pau@raquelpau

www.walkmod.com

@walkmod#walkmodevoxx

A bit of me

• 7 years working with Java

• Team leader in the research group DAMA-UPC

• Experience in Social Network Analysis, Deduplication algorithms &

recommendation engines

• Research publications about software engineering

• Currently involved in CoherentPaaS (EU project)

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Developers principle

DRYdon’t repeat yourself

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Coding conventions

“Set of guidelines for a specific programming language that recommend programming style, practices and methods for each aspect of a piece program written in this language” - wikipedia

• Define rules to accomplish DRY and make code readable

• Are partially supported by IDEs & Text editors

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... shall we dream again? yes!

walkmod• Tool to apply coding conventions

• Extensible tool by plugins (DIY)

• Respects your code changes

• Works with Java 8 code

• Open source + free

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Demo

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How walkmod works?

•Most code conventions can be automatically assured using code transformations. Types:

•Visitors (Visitor pattern): an straight-way java transformation

•Scripts: Polyglot inline transformations

•Template: DYSWYG transformations

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public class HelloVisitor extends VoidVisitor<VisitorContext>{...@Overwritepublic void visit(MethodDeclaration md, VisitorContext ctx){//TODO

}

@Overwritepublic void visit(FieldDeclaration fd, VisitorContext ctx){//TODO

}...

}

Visitor Example

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import org.walkmod.javalang.ast.body.ModifierSet;import java.lang.reflect.Modifier;import org.walkmod.javalang.ast.body.FieldDeclaration;

for(type in node.types){!  def fields = type.members.findAll({it instanceof FieldDeclaration});  for (field in fields){    int modifiers = ModifierSet.addModifier(field.modifiers, Modifier.PRIVATE);    modifiers = ModifierSet.removeModifier(modifiers, Modifier.PROTECTED);    modifiers = ModifierSet.removeModifier(modifiers, Modifier.PUBLIC);    field.setModifiers(modifiers);  }}

Script Example (Groovy)

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package ${query.resolve("root.package.name")};

import javax.persistence.Id;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;

public class ${query.resolve("type.name")} {

! @Id! @GeneratedValue(strategy = GenerationType.SEQUENCE)! Integer id;

! @Override! public boolean equals(Object o) {! ! if (o instanceof ${query.resolve("type.name")}) {! ! ! return id.equals(((${query.resolve("type.name")}) o).id);! ! }! ! return false;! }

}

Template Example (Groovy)

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How does walkmod respect your changes?

• Applies a semantic merge after each transformation.

• Each source code element (e.g. methods, fields, statements...) has an specific merge policy.

• Liberates code transformations from change-management responsibility.

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Can walkmod grow up?

• Creating new plugins and deploying them into maven

• The whole architecture is extensible and configurable.

• Plugins are loaded in runtime before applying transformations.

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Follow your dreams!

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Thanks / Creative Commons

•Presentation Template — Guillaume LaForge

•The Queen — A prestigious heritage with some inspiration from The Sex Pistols and funny Devoxxians

•Girl with a Balloon & Follow your dreams — Banksy

•Tube — Michael Keen