Type System and Signatures

def signature(returns: type, takes: list) -> str:
    """
    Generate JNI method signature string from return and parameter types.
    
    Args:
        returns: Return type (primitive, JavaClass, or array type)
        takes: List of parameter types
        
    Returns:
        JNI signature string (e.g., '(Ljava/lang/String;I)V')
    """

def with_signature(returns: type, takes: list) -> callable:
    """
    Decorator that generates signature and applies java_method decorator.
    
    Args:
        returns: Return type specification  
        takes: List of parameter type specifications
        
    Returns:
        Decorator function that applies java_method with generated signature
    """

from jnius import signature, JavaClass, jint, jvoid
from jnius import autoclass

String = autoclass('java.lang.String')

# Generate signatures for different method types
sig1 = signature(jvoid, [])  # '()V' - no parameters, void return
sig2 = signature(jint, [])   # '()I' - no parameters, int return  
sig3 = signature(String, [jint])  # '(I)Ljava/lang/String;' - int parameter, String return
sig4 = signature(jvoid, [String, jint])  # '(Ljava/lang/String;I)V' - String and int parameters

# Use with manual class definition
from jnius import JavaClass, MetaJavaClass, JavaMethod

class MyClass(JavaClass, metaclass=MetaJavaClass):
    __javaclass__ = 'com/example/MyClass'
    
    # Using generated signatures
    processData = JavaMethod(signature(String, [String, jint]))
    getValue = JavaMethod(signature(jint, []))

jboolean: type  # Java boolean type specifier
jbyte: type     # Java byte type specifier  
jchar: type     # Java char type specifier
jdouble: type   # Java double type specifier
jfloat: type    # Java float type specifier
jint: type      # Java int type specifier
jlong: type     # Java long type specifier
jshort: type    # Java short type specifier
jvoid: type     # Java void type specifier

def JArray(of_type: type) -> type:
    """
    Create array type specifier for signature generation.
    
    Args:
        of_type: Element type (primitive, JavaClass, or nested array)
        
    Returns:
        Array type specifier for use in signatures
    """

from jnius import JArray, jint, jdouble, signature, autoclass

String = autoclass('java.lang.String')

# Array type specifiers
int_array = JArray(jint)        # int[] → [I
double_array = JArray(jdouble)   # double[] → [D
string_array = JArray(String)    # String[] → [Ljava/lang/String;

# Multi-dimensional arrays
int_matrix = JArray(JArray(jint))  # int[][] → [[I

# Using in signatures
array_method_sig = signature(jvoid, [int_array])  # '([I)V'
matrix_method_sig = signature(int_matrix, [])     # '()[[I'

# Manual class with array methods
class ArrayProcessor(JavaClass, metaclass=MetaJavaClass):
    __javaclass__ = 'com/example/ArrayProcessor'
    
    processIntArray = JavaMethod(signature(jvoid, [int_array]))
    getStringArray = JavaMethod(signature(string_array, []))
    createMatrix = JavaMethod(signature(int_matrix, [jint, jint]))

@with_signature(returns, takes)
def method_name(self, ...): ...

from jnius import PythonJavaClass, MetaJavaClass, with_signature
from jnius import jint, jvoid, autoclass

String = autoclass('java.lang.String')

class Calculator(PythonJavaClass, metaclass=MetaJavaClass):
    __javaclass__ = 'com/example/Calculator'
    
    @with_signature(jint, [jint, jint])
    def add(self, a, b):
        pass  # Automatically gets signature '(II)I'
    
    @with_signature(jvoid, [String])
    def setName(self, name):
        pass  # Automatically gets signature '(Ljava/lang/String;)V'
    
    @with_signature(String, [])
    def getName(self):
        pass  # Automatically gets signature '()Ljava/lang/String;'

# Usage
calc = Calculator()
result = calc.add(5, 3)  # 8
calc.setName('MyCalculator')
name = calc.getName()    # 'MyCalculator'

def _jni_type_spec(jclass: type) -> str:
    """
    Generate JNI type specification string for a given type.
    
    Args:
        jclass: Type to analyze (JavaClass, primitive, or array)
        
    Returns:
        JNI type specification string
        
    Note:
        Internal function used by signature generation system.
    """

def get_signature(cls_tp) -> str:
    """
    Convert a Java Class type to its JNI signature string.
    
    Args:
        cls_tp: Java Class object or type
        
    Returns:
        JNI signature string for the class
        
    Note:
        Used by reflection system for type analysis.
    """