carfield.com.hk

PyUtil.java

2001-12-26T16:00:00Z

//: com:bruceeckel:python:PyUtil.java
// PythonInterpreter utilities
package com.bruceeckel.python;
import org.python.util.PythonInterpreter; 
import org.python.core.*; 
import java.util.*;

public class PyUtil { 
  /** Extract a Python tuple or array into a Java
  List (which can be converted into other kinds 
  of lists and sets inside Java). 
  @param interp The Python interpreter object
  @param pyName The id of the python list object
  */
  public static List 
  toList(PythonInterpreter interp, String pyName){
    return new ArrayList(Arrays.asList(
      (Object[])interp.get(
        pyName, Object[].class)));
  }
  /** Extract a Python dictionary into a Java Map
  @param interp The Python interpreter object
  @param pyName The id of the python dictionary
  */
  public static Map 
  toMap(PythonInterpreter interp, String pyName){
    PyList pa = ((PyDictionary)interp.get(
      pyName)).items();
    Map map = new HashMap();
    while(pa.__len__() != 0) {
      PyTuple po = (PyTuple)pa.pop();
      Object first = po.__finditem__(0)
        .__tojava__(Object.class);
      Object second = po.__finditem__(1)
        .__tojava__(Object.class);
      map.put(first, second);
    }
    return map;
  }
  /** Turn a Java Map into a PyDictionary, 
  suitable for placing into a PythonInterpreter
  @param map The Java Map object
  */
  public static PyDictionary 
  toPyDictionary(Map map) {
    Map m = new HashMap();
    Iterator it = map.entrySet().iterator();
    while(it.hasNext()) {
      Map.Entry e = (Map.Entry)it.next();
      m.put(Py.java2py(e.getKey()), 
        Py.java2py(e.getValue()));
    }
    // PyDictionary constructor wants a Hashtable:
    return new PyDictionary(new Hashtable(m));
  }
} ///:~

Test.java

2001-12-26T16:00:00Z

//: com:bruceeckel:python:Test.java
package com.bruceeckel.python;
import org.python.util.PythonInterpreter; 
import java.util.*;
import com.bruceeckel.test.*;

public class Test extends UnitTest {
  PythonInterpreter pi =
    new PythonInterpreter();
  public void test1() {
    pi.exec("tup=('fee','fi','fo','fum','fi')");
    List lst = PyUtil.toList(pi, "tup");
    System.out.println(lst);
    System.out.println(new HashSet(lst));
  }
  public void test2() {
    pi.exec("ints=[1,3,5,7,9,11,13,17,19]");
    List lst = PyUtil.toList(pi, "ints");
    System.out.println(lst);
  }
  public void test3() {
    pi.exec("dict = { 1 : 'a', 3 : 'b', " + 
      "5 : 'c', 9 : 'd', 11 : 'e'}");
    Map mp = PyUtil.toMap(pi, "dict");
    System.out.println(mp);
  }
  public void test4() {
    Map m = new HashMap();
    m.put("twas", new Integer(11));
    m.put("brillig", new Integer(27));
    m.put("and", new Integer(47));
    m.put("the", new Integer(42));
    m.put("slithy", new Integer(33));
    m.put("toves", new Integer(55));
    System.out.println(m);
    pi.set("m", PyUtil.toPyDictionary(m));
    pi.exec("print m");
    pi.exec("print m['slithy']");
  }
  public static void main(String args[]) {
    Test t = new Test();
    t.test1();
    t.test2();
    t.test3();
    t.test4();
  }
} ///:~

makefile

2001-12-26T16:00:00Z