Python Code Execution

public class PythonInterpreter implements AutoCloseable, Closeable {
    // Constructors
    public PythonInterpreter();
    public PythonInterpreter(PyObject dict);
    public PythonInterpreter(PyObject dict, PySystemState systemState);
    public static PythonInterpreter threadLocalStateInterpreter(PyObject dict);
    
    // Code execution
    public void exec(String code);
    public void exec(PyCode code);
    public void execfile(String filename);
    public PyObject eval(String code);
    public PyObject eval(PyCode code);
    
    // Variable management
    public void set(String name, Object value);
    public void set(String name, PyObject value);
    public PyObject get(String name);
    public PyObject get(String name, PyObject defaultValue);
    
    // I/O management
    public void setOut(java.io.Writer outStream);
    public void setOut(PyObject outStream);
    public void setErr(java.io.Writer errStream);
    public void setErr(PyObject errStream);
    public void setIn(java.io.Reader inStream);
    public void setIn(PyObject inStream);
    
    // Namespace management
    public PyObject getLocals();
    public void setLocals(PyObject locals);
    public PyObject getGlobals();
    public void setGlobals(PyObject globals);
    
    // System state access
    public PySystemState getSystemState();
    
    // Resource management
    public void close();
    public void cleanup();
}

PythonInterpreter interp = new PythonInterpreter();

// Execute simple Python code
interp.exec("print('Hello, World!')");
interp.exec("x = 2 + 3");

// Get result
PyObject result = interp.get("x");
System.out.println("Result: " + result.asInt()); // Output: 5

interp.close();

PythonInterpreter interp = new PythonInterpreter();

// Set Java variables in Python
interp.set("name", "Alice");
interp.set("age", 30);

// Execute Python code using those variables
interp.exec("""
    greeting = f"Hello, {name}! You are {age} years old."
    birth_year = 2024 - age
    """);

// Get results back to Java
String greeting = interp.get("greeting").toString();
int birthYear = interp.get("birth_year").asInt();

System.out.println(greeting);        // Hello, Alice! You are 30 years old.
System.out.println(birthYear);       // 1994

interp.close();

PythonInterpreter interp = new PythonInterpreter();

// Execute Python file
interp.execfile("/path/to/script.py");

// Access variables defined in the file
PyObject result = interp.get("some_variable");

interp.close();

public class InteractiveInterpreter extends PythonInterpreter {
    public InteractiveInterpreter();
    public InteractiveInterpreter(PyObject locals);
    public InteractiveInterpreter(PyObject locals, PySystemState systemState);
    
    // Interactive execution
    public boolean runsource(String source);
    public boolean runsource(String source, String filename);
    public boolean runsource(String source, String filename, CompileMode mode);
    
    // Code execution
    public void runcode(PyObject code);
    
    // Compilation
    public PyCode compile(String source, String filename, CompileMode mode);
    
    // Error handling for interactive use
    public void showexception(PyException exc);
    public void showtraceback();
    public void showsyntaxerror(String filename);
    
    // Output methods
    public void write(String data);
    
    // Buffer management
    public StringBuilder buffer;
    public void resetbuffer();
    
    // Debugging support
    public void interrupt(ThreadState ts);
}

InteractiveInterpreter interp = new InteractiveInterpreter();

// Returns true if more input is needed (incomplete statement)
boolean needsMore = interp.runsource("if True:");
System.out.println(needsMore); // true

// Complete the statement
needsMore = interp.runsource("    print('Complete!')");
System.out.println(needsMore); // false - statement executed

interp.close();

public class InteractiveConsole extends InteractiveInterpreter {
    public InteractiveConsole();
    public InteractiveConsole(PyObject locals);
    public InteractiveConsole(PyObject locals, String filename);
    
    // Console interaction
    public void interact();
    public void interact(String banner);
    public String raw_input();
    public String raw_input(PyObject prompt);
    
    // Input handling
    public boolean push(String line);
    public void resetbuffer();
}

InteractiveConsole console = new InteractiveConsole();

// Start interactive session with custom banner
console.interact("Welcome to Jython Console!");

// This will start an interactive Python REPL that accepts input
// and provides output until the user exits

public abstract class PyCode extends PyObject {
    public abstract PyObject call(ThreadState ts, PyFrame frame);
    public PyObject call(PyObject globals);
    public PyObject call(PyObject globals, PyObject locals);
}

// Factory methods in Py class
public final class Py {
    public static PyCode newCode(int argcount, String varnames[], 
                                String filename, String name, 
                                boolean args, boolean keywords, 
                                PyFunctionTable funcs, int func_id);
    public static PyCode newJavaCode(Class<?> cls, String name);
}

PythonInterpreter interp = new PythonInterpreter();

// Compile code once
PyCode code = interp.compile("result = x * y + z", "<string>", CompileMode.exec);

// Execute multiple times with different variables
interp.set("x", 2);
interp.set("y", 3);
interp.set("z", 4);
interp.eval(code);
System.out.println(interp.get("result")); // 10

interp.set("x", 5);
interp.set("y", 6);
interp.set("z", 7);
interp.eval(code);
System.out.println(interp.get("result")); // 37

interp.close();

public class PythonInterpreter {
    public static void initialize(Properties preProperties, 
                                Properties postProperties, 
                                String[] argv);
}

Properties preProps = new Properties();
preProps.setProperty("python.home", "/path/to/jython");

Properties postProps = new Properties();
postProps.setProperty("python.path", "/path/to/modules:/another/path");

String[] args = {"arg1", "arg2"};

PythonInterpreter.initialize(preProps, postProps, args);

PythonInterpreter interp = new PythonInterpreter();
// Interpreter now uses custom configuration
interp.close();

public class PythonInterpreter {
    public static PythonInterpreter threadLocalStateInterpreter(PyObject dict);
}

// Create thread-local interpreter
PythonInterpreter interp = PythonInterpreter.threadLocalStateInterpreter(null);

// Each thread gets its own interpreter instance
// Safe for concurrent use across threads
interp.exec("print('Thread:', threading.current_thread().name)");

interp.close();

// Try-with-resources (recommended)
try (PythonInterpreter interp = new PythonInterpreter()) {
    interp.exec("print('Hello, World!')");
    // Automatically closed
}

// Manual cleanup
PythonInterpreter interp = new PythonInterpreter();
try {
    interp.exec("print('Hello, World!')");
} finally {
    interp.close();
}

try {
    interp.exec("undefined_variable");
} catch (PyException e) {
    if (e.match(Py.NameError)) {
        System.out.println("Variable not found: " + e.value);
    }
}