KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > python > core > PyFieldDescr


1 package org.python.core;
2
3 import java.lang.reflect.Field JavaDoc;
4 import java.lang.reflect.Modifier JavaDoc;
5
6 public class PyFieldDescr extends PyDescriptor {
7
8     private Field JavaDoc field;
9     private Class JavaDoc field_type;
10     private boolean readonly;
11
12     public PyFieldDescr(String JavaDoc name, Class JavaDoc c, String JavaDoc field_name) {
13         this(name, c, field_name, false);
14     }
15
16     public PyFieldDescr(
17         String JavaDoc name,
18         Class JavaDoc c,
19         String JavaDoc field_name,
20         boolean readonly) {
21         this.name = name;
22         this.dtype = PyType.fromClass(c);
23         try {
24             field = c.getField(field_name);
25         } catch (NoSuchFieldException JavaDoc e) {
26             throw Py.SystemError("bogus attribute spec");
27         }
28         int modifiers = field.getModifiers();
29         if (Modifier.isStatic(modifiers)) {
30             throw Py.SystemError("static attributes not supported");
31         }
32         this.readonly = readonly || Modifier.isFinal(modifiers);
33         field_type = field.getType();
34
35     }
36
37     public String JavaDoc toString() {
38         return "<member '" + name + "' of '"+dtype.fastGetName()+"' objects>";
39     }
40
41     /**
42      * @see org.python.core.PyObject#__get__(org.python.core.PyObject, org.python.core.PyObject)
43      */
44     public PyObject __get__(PyObject obj, PyObject type) {
45         try {
46             if (obj != null) {
47                 PyType objtype = obj.getType();
48                 if (objtype != dtype && !objtype.isSubType(dtype))
49                     throw get_wrongtype(objtype);
50                 return Py.java2py(field.get(obj));
51             }
52             return this;
53         } catch (IllegalArgumentException JavaDoc e) {
54             throw Py.JavaError(e);
55
56         } catch (IllegalAccessException JavaDoc e) {
57             throw Py.JavaError(e); // unexpected
58 }
59     }
60
61     /**
62      * @see org.python.core.PyObject#__set__(org.python.core.PyObject, org.python.core.PyObject)
63      */
64     public void __set__(PyObject obj, PyObject value) {
65         try {
66             // obj != null
67 PyType objtype = obj.getType();
68             if (objtype != dtype && !objtype.isSubType(dtype))
69                 throw get_wrongtype(objtype);
70             Object JavaDoc converted = value.__tojava__(field_type);
71             if (converted == Py.NoConversion) {
72                 throw Py.TypeError(""); // xxx
73 }
74             field.set(obj, converted);
75         } catch (IllegalArgumentException JavaDoc e) {
76             throw Py.JavaError(e);
77         } catch (IllegalAccessException JavaDoc e) {
78             throw Py.JavaError(e); // unexpected
79 }
80     }
81
82     /**
83      * @see org.python.core.PyObject#implementsDescrSet()
84      */
85     public boolean implementsDescrSet() {
86         return !readonly;
87     }
88
89     /**
90      * @see org.python.core.PyObject#isDataDescr()
91      */
92     public boolean isDataDescr() {
93         return true;
94     }
95
96 }
97
Popular Tags