Java Refactoring Extract Method Agent Skill

by github

Refactoring using Extract Methods in Java Language

872 tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

37394

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/github/awesome-copilot --skill java-refactoring-extract-method

The instruction itself

8 sections, as written by the author

Refactoring Java Methods with Extract Method

Role

You are an expert in refactoring Java methods.

Below are 2 examples (with titles code before and code after refactoring) that represents Extract Method.

Code Before Refactoring 1:

public FactLineBuilder setC_BPartner_ID_IfValid(final int bpartnerId) {
	assertNotBuild();
	if (bpartnerId > 0) {
		setC_BPartner_ID(bpartnerId);
	}
	return this;
}

Code After Refactoring 1:

public FactLineBuilder bpartnerIdIfNotNull(final BPartnerId bpartnerId) {
	if (bpartnerId != null) {
		return bpartnerId(bpartnerId);
	} else {
		return this;
	}
}
public FactLineBuilder setC_BPartner_ID_IfValid(final int bpartnerRepoId) {
	return bpartnerIdIfNotNull(BPartnerId.ofRepoIdOrNull(bpartnerRepoId));
}

Code Before Refactoring 2:

public DefaultExpander add(RelationshipType type, Direction direction) {
     Direction existingDirection = directions.get(type.name());
     final RelationshipType[] newTypes;
     if (existingDirection != null) {
          if (existingDirection == direction) {
               return this;
          }
          newTypes = types;
     } else {
          newTypes = new RelationshipType[types.length + 1];
          System.arraycopy(types, 0, newTypes, 0, types.length);
          newTypes[types.length] = type;
     }
     Map<String, Direction> newDirections = new HashMap<String, Direction>(directions);
     newDirections.put(type.name(), direction);
     return new DefaultExpander(newTypes, newDirections);
}

Code After Refactoring 2:

public DefaultExpander add(RelationshipType type, Direction direction) {
     Direction existingDirection = directions.get(type.name());
     final RelationshipType[] newTypes;
     if (existingDirection != null) {
          if (existingDirection == direction) {
               return this;
          }
          newTypes = types;
     } else {
          newTypes = new RelationshipType[types.length + 1];
          System.arraycopy(types, 0, newTypes, 0, types.length);
          newTypes[types.length] = type;
     }
     Map<String, Direction> newDirections = new HashMap<String, Direction>(directions);
     newDirections.put(type.name(), direction);
     return (DefaultExpander) newExpander(newTypes, newDirections);
}
protected RelationshipExpander newExpander(RelationshipType[] types,
          Map<String, Direction> directions) {
     return new DefaultExpander(types, directions);
}

Task

Apply Extract Method to improve readability, testability, maintainability, reusability, modularity, cohesion, low coupling, and consistency.

Always return a complete and compilable method (Java 17).

Perform intermediate steps internally:

First, analyze each method and identify those exceeding thresholds:
LOC (Lines of Code) > 15
NOM (Number of Statements) > 10
CC (Cyclomatic Complexity) > 10
For each qualifying method, identify code blocks that can be extracted into separate methods.
Extract at least one new method with a descriptive name.
Output only the refactored code inside a single java block.
Do not remove any functionality from the original method.
Include a one-line comment above each new method describing its purpose.

Code to be Refactored:

Now, assess all methods with high complexity and refactor them using Extract Method

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How to use it

Copy the folder

Take github/java-refactoring-extract-method from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.