---
name: java-refactoring-extract-method
description: 'Refactoring using Extract Methods in Java Language'
---
# 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:
```java
public FactLineBuilder setC_BPartner_ID_IfValid(final int bpartnerId) {
assertNotBuild();
if (bpartnerId > 0) {
setC_BPartner_ID(bpartnerId);
}
return this;
}
```
## Code After Refactoring 1:
```java
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:
```java
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:
```java
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**
