java-to-swift

Java to Swift Conversion

Overview

Converts Java 1.8 classes to Swift 5.0+ struct objects conforming to Codable. Output as markdown code blocks only — never modify project files.

Core Constraint

CRITICAL: Output Swift struct definitions as markdown code blocks only. Do NOT modify, edit, or alter any project files.

Type Mapping

Java Type	Swift Type
int / Integer	Int
long / Long	Int64
float / Float	Float
double / Double	Double
boolean / Boolean	Bool
String	String
BigDecimal / decimal	Double (default) or String (with @BigDecimalToString)
Date	Date
Timestamp	TimeInterval
List<T>	[T]
Map<K,V>	[K: V]

Nullability Rules

Java Annotation	Swift Type
@NonNull / @NotNull	Non-optional (String)
No annotation / @Nullable	Optional (String?)

Default: All properties are optional unless explicitly marked non-null.

Naming Conventions

Struct names: PascalCase (OrderDetails, UserProfile, PaymentRequest)

Property names: ⚠️ KEEP IDENTICAL TO JAVA/SERVER-SIDE — preserves Codable serialization.

// ✅ Correct
struct OrderRequest: Codable {
    let orderId: String        // matches Java field name
    let total_amount: String?  // preserves snake_case
}

Swift's Codable maps property names directly to JSON keys — changing names breaks serialization.

Inheritance Handling

Swift structs don't support inheritance. Always flatten the hierarchy:

1. Trace full inheritance chain — read all parent class files
2. If any parent is BaseReq → EXCLUDE all BaseReq properties (handled by network layer)
3. Combine all remaining properties from parent + child into one struct
4. Document property source with inline comments

struct OrderRequest: Codable {
    // From ApiRequest
    let userId: String

    // From OrderRequest
    let orderId: Int64

    // Note: BaseReq properties (token, timestamp) excluded — handled by network layer
}

Documentation

Migrate Java comments to Swift using /// triple-slash format:

• Preserve original language (Chinese stays Chinese, English stays English)
• Place comments immediately above each property
• For properties without Java comments, add brief descriptive comment

Structure Requirements

All converted structs must:

• Be defined as struct (not class)
• Conform to Codable protocol
• Use let for all properties (immutable)
• Flatten all inherited properties into a single struct

Step-by-Step Workflow

1. Analyze Java class — properties, annotations, types, inheritance
2. If inheritance detected → request/read parent class files
3. Handle BaseReq exclusion if applicable
4. Create Swift struct with Codable conformance
5. Apply type mapping (including @BigDecimalToString)
6. Apply nullability (@NonNull → non-optional, else optional)
7. Use let for all properties
8. Keep property names identical to Java/server-side
9. Migrate comments with /// preserving original language

Validation Checklist

• [ ] @NonNull/@NotNull properties are non-optional
• [ ] All other properties are optional (?)
• [ ] Struct conforms to Codable
• [ ] All properties use let
• [ ] Inheritance detected and parent classes analyzed
• [ ] All inherited properties flattened into single struct
• [ ] BaseReq properties excluded if applicable
• [ ] Property names identical to server-side model
• [ ] Output is markdown code block only (no file modifications)